ชี้แจง - ถัว เฉลี่ยเคลื่อนที่ - TCP

ชี้แจง - ถัว เฉลี่ยเคลื่อนที่ - TCP

ที่ดีที่สุด   Forex   ซื้อขาย โบรกเกอร์ ออสเตรเลีย
บันไดเลื่อน ซื้อขาย ระบบ
Forex- zar -usd


Etrade ตัวเลือก ค่าใช้จ่าย Cest - quoi -le -forex- ซื้อขาย ที่ดีที่สุด Forex -trading- สัญญาณ ฟรี Forex- ซื้อขาย บัญชี สิงคโปร์ Forex ซื้อขาย หลักสูตร ใน มาเลเซีย Binary ตัวเลือก โบรกเกอร์ สัญญาณ

คู่มือการกำหนดค่าบริการคุณภาพของ Cisco IOS 12.2 ภาพรวมการหลีกเลี่ยงความแออัดการหลีกเลี่ยงความแออัดการตรวจสอบปริมาณการจราจรบนเครือข่ายด้วยความพยายามที่จะคาดการณ์ล่วงหน้าและหลีกเลี่ยงปัญหาความแออัดของเครือข่าย หลีกเลี่ยงความแออัดได้โดยการลดแพ็กเก็ต ในกลไกการหลีกเลี่ยงความแออัดที่นิยมใช้กันมากคือ Random Early Detection (RED) ซึ่งเหมาะสำหรับเครือข่ายการขนส่งความเร็วสูง Cisco IOS QoS มีการใช้ RED ซึ่งเมื่อกำหนดค่าจะควบคุมเมื่อเราเตอร์ลดการรับส่งข้อมูล ถ้าคุณไม่ได้กำหนดค่า Weighted Random Early Detection (WRED) เราเตอร์จะใช้กลไกการปล่อย packet แบบดีฟอลต์ที่ชื่อว่า tail drop สำหรับคำอธิบายเกี่ยวกับความแออัดของเครือข่ายให้ดูที่บทสรุปคุณภาพของภาพรวมของบริการ .quot บทนี้จะอธิบายถึงรูปแบบของกลไกการหลีกเลี่ยงความแออัดโดยใช้คุณสมบัติ Cisco IOS QoS กล่าวถึงคุณสมบัติต่อไปนี้: วางหาง นี่คือพฤติกรรมการหลีกเลี่ยงความแออัดโดยเริ่มต้นเมื่อ WRED ไม่ได้รับการกำหนดค่า WRED WRED และกระจาย WRED (DWRED) ทั้งสองอย่างคือการใช้งานของซิสโก้ในการปรับแต่งความสามารถของอัลกอริทึม RED ด้วยคุณสมบัติ Precedence ของ IP ในส่วนเกี่ยวกับ WRED จะมีการกล่าวถึงคุณลักษณะที่เกี่ยวข้องต่อไปนี้: WRED แบบไหล WRED แบบไหลจะขยาย WRED เพื่อให้เกิดความเป็นธรรมยิ่งขึ้นกับการไหลทั้งหมดบนอินเทอร์เฟซสำหรับการแพ็คเก็ตจะลดลง DiffServ ตามมาตรฐาน WRED DiffServ Compliant WRED ขยาย WRED เพื่อสนับสนุนบริการที่แตกต่าง (DiffServ) และ Assured Forwarding (AF) ต่อ Hop Behavior (PHB) คุณลักษณะนี้ช่วยให้ลูกค้าสามารถใช้ AF PHB โดยการทำสีแพ็คเก็ตตามค่าจุดรหัส (DSCP) ของบริการที่แตกต่างกันและกำหนดความน่าจะเป็นที่ต้องการให้กับแพ็คเก็ตเหล่านั้น สำหรับข้อมูลเกี่ยวกับวิธีการกำหนดค่า WRED, DWRED, WRED แบบกระจายตามปริมาณและ DiffServ Compliant WRED ให้ดูที่บท quotConfiguring Weighted Random Early Detectionquot ในหนังสือเล่มนี้ หางยาวถือว่าการจราจรทั้งหมดอย่างเท่าเทียมกันและไม่แตกต่างระหว่างชั้นเรียนของการบริการ คิวเติมในช่วงเวลาที่มีการแออัด เมื่อคิวเอาต์พุตเต็มและการลดลงของหางจะส่งผลให้แพ็คเก็ตจะลดลงจนกว่าจะมีการขจัดความแออัดและคิวจะไม่เต็มอีกต่อไป Randomed Early Detection ในส่วนนี้จะให้คำแนะนำสั้น ๆ เกี่ยวกับแนวคิด RED และที่อยู่ WRED การใช้งาน Cisco ของ RED สำหรับแพลตฟอร์ม Cisco IOS มาตรฐาน WRED หลีกเลี่ยงปัญหาโลกาภิวัฒน์ที่เกิดขึ้นเมื่อหางลดลงใช้เป็นกลไกหลีกเลี่ยงความแออัดของเราเตอร์ การซิงโครไนส์ทั่วโลกเกิดขึ้นเป็นคลื่นของ crested congestion เท่านั้นที่จะตามด้วย troughs ในระหว่างที่ไม่ได้รับการเชื่อมโยงการส่งข้อมูล การซิงโครไนส์สากลของโฮสต์ TCP อาจเกิดขึ้นเนื่องจากแพ็คเก็ตถูกทิ้งทั้งหมดพร้อมกัน การซิงโครไนส์โกลบอลจะแสดงเมื่อโฮสต์ TCP หลายตัวลดอัตราการส่งข้อมูลเพื่อตอบสนองต่อการลดแพ็กเก็ตจากนั้นเพิ่มอัตราการส่งข้อมูลอีกครั้งเมื่อความแออัดลดลง เกี่ยวกับการตรวจสอบก่อนหน้าแบบสุ่มกลไกของ RED ถูกเสนอโดย Sally Floyd และ Van Jacobson ในช่วงต้นปี 1990 เพื่อแก้ไขปัญหาความแออัดของเครือข่ายในลักษณะตอบสนองมากกว่าปฏิกิริยา กลไกการทำงานร่วมกันของ RED คือสมมติฐานที่ว่าการเข้าชมส่วนใหญ่จะทำงานบนการใช้งานการขนส่งข้อมูลซึ่งมีความไวต่อการสูญเสียและจะชะลอตัวลงชั่วคราวเมื่อการเข้าชมบางส่วนลดลง TCP ซึ่งตอบสนองการจราจรที่ลดลงอย่างเหมาะสมโดยการชะลอการรับส่งข้อมูลการจราจรทำให้สามารถลดการจราจรของ RED ได้อย่างมีประสิทธิภาพในฐานะกลไกการส่งสัญญาณที่หลีกเลี่ยงการแออัด TCP ถือเป็นการขนส่งทางเครือข่ายที่ใช้กันมากที่สุด เนื่องจากมี TCP อยู่ที่แพร่หลาย RED จึงมีกลไกการหลีกเลี่ยงความแออัดที่แพร่หลายและมีประสิทธิภาพ ในการพิจารณาถึงประโยชน์ของ RED เมื่อการขนส่งที่มีประสิทธิภาพเช่น TCP แพร่หลายมากคุณควรคำนึงถึงผลกระทบเชิงลบอย่างร้ายแรงต่อการใช้ RED หากเปอร์เซ็นต์การรับส่งข้อมูลไม่สำคัญในการตอบสนองต่อการสูญหายของแพ็คเก็ต Novell NetWare หรือ AppleTalk ไม่สามารถตอบสนองต่อการสูญหายของแพ็กเก็ตได้อย่างเหมาะสมดังนั้นคุณจึงไม่ควรใช้ RED สำหรับพวกเขา วิธีการทำงาน RED มีเป้าหมายเพื่อควบคุมขนาดของคิวโดยเฉลี่ยโดยระบุให้กับโฮสต์ปลายทางเมื่อพวกเขาควรชะลอการส่งแพ็คเก็ต RED ใช้ประโยชน์จากกลไกการควบคุมความแออัดของ TCP โดยการสุ่มวางแพ็คเก็ตก่อนที่จะมีความคับคั่งสูง RED จะบอกแหล่งที่มาของแพคเก็ตเพื่อลดอัตราการส่งข้อมูล สมมติว่าแหล่งที่มาของแพคเก็ตใช้ TCP จะลดอัตราการส่งข้อมูลจนกว่าแพ็คเก็ตทั้งหมดจะไปถึงจุดหมายปลายทางของพวกเขาซึ่งบ่งบอกว่าแออัดถูกล้าง คุณสามารถใช้ RED เพื่อก่อให้เกิด TCP เพื่อชะลอการรับส่งข้อมูลได้ TCP ไม่เพียง แต่หยุดชั่วคราว แต่จะรีสตาร์ทได้รวดเร็วและปรับอัตราการส่งข้อมูลให้เป็นอัตราที่เครือข่ายสามารถรองรับได้ RED แจกจ่ายความสูญเสียในเวลาและรักษาความลึกของคิวโดยปกติขณะดูดซับแรงกระแทก เมื่อเปิดใช้งานอินเทอร์เฟซ RED จะเริ่มวางแพ็คเก็ตเมื่อความแออัดเกิดขึ้นในอัตราที่คุณเลือกในระหว่างการตั้งค่า สำหรับคำอธิบายเกี่ยวกับวิธีที่การใช้งาน Cisco WRED กำหนดพารามิเตอร์ที่จะใช้ในการคำนวณขนาดคิว WRED และวิธีกำหนดค่าที่เหมาะสมเพื่อใช้สำหรับปัจจัยด้านน้ำหนักโปรดดูที่ส่วน quot Queue Sizequot ในภายหลังในบทนี้ ความน่าจะเป็น Packet Drop ความน่าจะเป็น Packet Drop น่าจะขึ้นอยู่กับเกณฑ์ขั้นต่ำเกณฑ์สูงสุดและเครื่องหมายความน่าจะเป็นเครื่องหมาย เมื่อความลึกของแถวโดยเฉลี่ยอยู่เหนือเกณฑ์ต่ำสุด RED จะเริ่มวางแพ็คเก็ต อัตราการลดลงของแพ็คเก็ตจะเพิ่มขึ้นเป็นเชิงเส้นเนื่องจากขนาดของคิวโดยเฉลี่ยจะเพิ่มขึ้นจนกว่าขนาดของคิวเฉลี่ยจะถึงเกณฑ์สูงสุด เครื่องหมายความเป็นไปได้คือเศษของแพ็คเก็ตที่ลดลงเมื่อระดับความยาวของคิวเฉลี่ยอยู่ที่เกณฑ์สูงสุด ตัวอย่างเช่นถ้าตัวหารเป็น 512 หนึ่งในทุก 512 แพ็คเก็ตจะลดลงเมื่อคิวเฉลี่ยอยู่ที่เกณฑ์สูงสุด เมื่อขนาดคิวโดยเฉลี่ยสูงกว่าเกณฑ์สูงสุดแพ็คเก็ตทั้งหมดจะถูกลดลง รูปที่ 9 สรุปความน่าจะเป็นของ packet drop รูปที่ 9 ความน่าจะเป็น Packet Drop Packet Red ค่า threshold ต่ำสุดควรตั้งค่าให้สูงพอที่จะเพิ่มการใช้งาน Link ถ้าค่าต่ำสุดต่ำเกินไปแพ็กเก็ตอาจถูกลดลงโดยไม่จำเป็นและไม่สามารถใช้การเชื่อมโยงการส่งข้อมูลได้อย่างเต็มที่ ความแตกต่างระหว่างเกณฑ์สูงสุดและเกณฑ์ต่ำสุดควรใหญ่พอที่จะหลีกเลี่ยงการซิงโครไนส์ของโฮสต์ TCP ทั่วโลก (การซิงโครไนส์ทั่วโลกของโฮสต์ TCP อาจเกิดขึ้นได้เนื่องจากโฮสต์ TCP จำนวนมากลดอัตราการส่ง) ถ้าความแตกต่างระหว่างเกณฑ์สูงสุดและต่ำสุดมีขนาดเล็กเกินไปแพ็คเก็ตจำนวนมากอาจถูกลดลงพร้อม ๆ กันทำให้เกิดการซิงโครไนส์ทั่วโลก วิธี TCP จัดการกับการสูญเสียการจราจรหมายเหตุส่วนของคำว่า TCP จับ Traffic Lossquot และคำอธิบายว่า Router โต้ตอบกับ TCPquot มีข้อมูลรายละเอียดที่คุณไม่จำเป็นต้องอ่านเพื่อที่จะใช้ WRED หรือมีความรู้สึกทั่วไปเกี่ยวกับความสามารถของ RED ถ้าคุณต้องการเข้าใจว่าเหตุใดปัญหาเกี่ยวกับการซิงโครไนส์ทั่วโลกจึงเกิดขึ้นเมื่อเกิดความแออัดขึ้นเมื่อมีการใช้หางดิงโดยค่าเริ่มต้นและวิธีการที่ RED ระบุตำแหน่งเหล่านี้โปรดอ่านบทเหล่านี้ เมื่อผู้รับ TCP trafficcalled รับข้อมูลเซ็กเมนต์ข้อมูลจะตรวจสอบเลขที่ลำดับข้อมูลสี่ส่วน (32 บิต) ของกลุ่มนั้นเทียบกับจำนวนที่ผู้รับคาดหวังซึ่งจะบ่งบอกว่าได้รับข้อมูลข้อมูลตามลำดับ ถ้าหมายเลขตรงกันผู้รับจะส่งข้อมูลทั้งหมดที่เก็บไว้ในแอ็พพลิเคชันเป้าหมายจากนั้นจะอัพเดตหมายเลขลำดับเพื่อให้สอดคล้องกับหมายเลขถัดไปตามลำดับและสุดท้ายก็ส่งชุดรับทราบข้อมูล (ACK) ไปยังผู้ส่งทันที มันกำหนดการ ACK ที่จะส่งไปยังผู้ส่งหลังจากที่ล่าช้าสั้น ACK แจ้งผู้ส่งว่าผู้รับได้รับข้อมูลทั้งหมดตั้งแต่ถึงกลุ่ม แต่ไม่รวมหมายเลขที่มีหมายเลขลำดับใหม่ ผู้รับมักจะพยายามส่ง ACK เพื่อตอบสนองต่อข้อมูลสลับที่พวกเขาได้รับจากพวกเขาส่ง ACK เนื่องจากสำหรับแอ็พพลิเคชันจำนวนมากถ้าผู้รับรอช้าๆจะสามารถตอบรับการตอบรับข้อความตอบกลับไปยังผู้ส่งได้อย่างมีประสิทธิภาพ อย่างไรก็ตามเมื่อผู้รับรับข้อมูลข้อมูลไม่เป็นไปตามคำสั่งจะตอบสนองทันทีด้วย ACK เพื่อสั่งให้ผู้ส่งส่งข้อมูลข้อมูลที่สูญหายไป เมื่อผู้ส่งได้รับ ACK จะทำให้การกำหนดนี้: กำหนดว่าข้อมูลใดมียอดคงเหลือหรือไม่ ถ้าไม่มีข้อมูลใด ๆ ผู้ส่งระบุว่า ACK เป็นแบบ keepalive ซึ่งหมายถึงให้สายใช้งานได้และไม่มีอะไรเกิดขึ้น หากข้อมูลมีความโดดเด่นผู้ส่งจะกำหนดว่า ACK ระบุว่าผู้รับได้รับข้อมูลบางส่วนหรือไม่มีอยู่หรือไม่ ถ้า ACK ระบุว่าได้รับข้อมูลที่ส่งมาผู้ส่งจะกำหนดว่าได้รับเครดิตใหม่เพื่อให้สามารถส่งข้อมูลได้มากขึ้นหรือไม่ เมื่อ ACK ระบุว่าไม่ได้รับข้อมูลที่ส่งมาและมีข้อมูลที่ค้างอยู่ผู้ส่งจะตีความ ACK เป็น ACK ที่ส่งซ้ำ เงื่อนไขนี้บ่งชี้ว่าได้รับข้อมูลบางอย่างจากคำสั่งบังคับให้ผู้รับส่ง ACK แรกและได้รับเซ็กเมนต์ข้อมูลที่สองที่ไม่ได้รับคำสั่งบังคับให้ผู้รับส่ง ACK ที่สอง ในกรณีส่วนใหญ่ผู้รับจะได้รับสองกลุ่มที่ไม่ได้รับคำสั่งเนื่องจากกลุ่มข้อมูลหนึ่ง ๆ ถูกทิ้ง เมื่อผู้ส่ง TCP ตรวจพบส่วนข้อมูลที่ลดลงระบบจะส่งกลุ่มนี้ซ้ำ จากนั้นจะปรับอัตราการส่งข้อมูลให้เท่ากับครึ่งหนึ่งของช่วงก่อนที่จะมีการตรวจพบหยด นี่คือลักษณะการทำงานปิดกั้น TCP หรือช้าลง แม้ว่าปัญหานี้จะตอบสนองต่อความแออัดได้อย่างเหมาะสมปัญหาอาจเกิดขึ้นได้เมื่อมีการใช้งาน TCP sessions หลายครั้งพร้อมกันกับเราเตอร์เดียวกันและผู้ส่ง TCP ทั้งหมดจะชะลอการส่งแพ็คเก็ตในเวลาเดียวกัน วิธีการทำงานของ Router กับ TCP หมายเหตุส่วน TCPHN จัดการกับการสูญเสียการจราจรและคำอธิบายว่าเราเตอร์โต้ตอบกับ TCPquot มีข้อมูลรายละเอียดที่คุณไม่จำเป็นต้องอ่านเพื่อที่จะใช้ WRED หรือมีความรู้สึกทั่วไปของความสามารถของ RED ถ้าคุณต้องการเข้าใจว่าเหตุใดปัญหาเกี่ยวกับการซิงโครไนส์ทั่วโลกจึงเกิดขึ้นเมื่อเกิดความแออัดขึ้นเมื่อมีการใช้หางดิงโดยค่าเริ่มต้นและวิธีการที่ RED ระบุตำแหน่งเหล่านี้โปรดอ่านบทเหล่านี้ เพื่อดูว่าเราเตอร์โต้ตอบกับ TCP เราจะดูตัวอย่าง ในตัวอย่างนี้โดยเฉลี่ยเราเตอร์ได้รับการเข้าชมจากสตรีม TCP หนึ่ง ๆ ทุกๆทุกๆ 10 และทุกๆข้อความที่ 100 หรือ 200 ในส่วนติดต่อใน MAE-EAST หรือ FIX-WEST เราเตอร์สามารถจัดการกับเซสชัน TCP ได้หลายครั้ง เนื่องจากการไหลของเครือข่ายเป็นส่วนเพิ่มจึงมีความเป็นไปได้สูงที่เมื่อปริมาณการเข้าชมเกินขีด จำกัด การรับส่ง (TQL) จะมากเกินขีด จำกัด อย่างไรก็ตามยังมีความเป็นไปได้สูงที่ความลึกของการจราจรที่มากเกินไปจะเป็นแบบชั่วคราวและการจราจรจะไม่อยู่ลึกเกินกว่ายกเว้นจุดที่การจราจรผสานหรือที่ขอบเราท์เตอร์ ถ้าเราเตอร์ลดการรับส่งข้อมูลทั้งหมดที่เกิน TQL ตามที่ทำเมื่อหางลัดถูกใช้โดยค่าเริ่มต้นเซสชัน TCP จำนวนมากพร้อมกันจะเข้าสู่การเริ่มต้นช้า ดังนั้นการเข้าชมจึงทำงานช้าลงจนสุดแล้วกระแสทั้งหมดเริ่มช้าอีกครั้งกิจกรรมนี้จะสร้างเงื่อนไขของการซิงโครไนส์ทั่วโลก อย่างไรก็ตามหากเราเตอร์ไม่มีการเข้าชมเช่นในกรณีที่มีการใช้งานการจัดคิวอย่างเช่นการจัดคิวอย่างยุติธรรมหรือการจัดคิวที่กำหนดเอง (CQ) ข้อมูลจะถูกจัดเก็บไว้ในหน่วยความจำหลักทำให้ประสิทธิภาพของเราเตอร์ลดลงอย่างมาก เมื่อสั่งให้เซสชัน TCP หนึ่งครั้งทำงานช้าลง RED จะแก้ไขปัญหาที่อธิบายไว้เพื่อให้สามารถใช้แบนด์วิธได้เต็มที่แทนที่จะใช้การแสดงผลเป็น crests และ troughs ของ traffic เกี่ยวกับ WRED WRED รวมความสามารถของอัลกอริทึม RED กับคุณสมบัติ Precedence ของ IP เพื่อจัดเตรียมการจัดการการรับส่งข้อมูลพิเศษของแพคเก็ตที่มีลำดับความสำคัญสูงกว่า WRED สามารถเลือกละทิ้งการรับส่งข้อมูลที่มีลำดับความสำคัญต่ำกว่าได้เมื่ออินเทอร์เฟซเริ่มมีการแออัดและให้ประสิทธิภาพการทำงานที่แตกต่างกันสำหรับแต่ละชั้นการให้บริการ คุณสามารถกำหนดค่า WRED เพื่อไม่สนใจลำดับความสำคัญของ IP เมื่อทำการตัดสินใจแบบ drop เพื่อให้พฤติกรรม RED ที่ไม่มีการชั่งน้ำหนักเป็นไปได้ สำหรับอินเทอร์เฟซที่กำหนดค่าให้ใช้คุณลักษณะ Resource Reservation Protocol (RSVP) WRED จะเลือกแพ็คเก็ตจากกระแสอื่น ๆ ที่จะลดลงแทนที่จะเป็นกระแส RSVP นอกจากนี้ความสำคัญของ IP จะควบคุมการแพ็คเก็ตที่ถูกลดทราฟฟิกที่อยู่ในลำดับความสำคัญที่ต่ำกว่ามีอัตราการลดลงที่สูงขึ้นดังนั้นจึงมีแนวโน้มที่จะถูกลดทอนลง WRED แตกต่างจากเทคนิคการหลีกเลี่ยงความแออัดอื่น ๆ เช่นกลยุทธ์การเข้าคิวเนื่องจากพยายามคาดการณ์และหลีกเลี่ยงความแออัดมากกว่าการควบคุมความแออัดเมื่อเกิดเหตุการณ์ขึ้น ทำไมต้องใช้ WRED WRED ทำให้สามารถตรวจจับความแออัดได้เร็วขึ้นและมีการเข้าชมหลายชั้น นอกจากนี้ยังช่วยป้องกันการซิงโครไนส์ทั่วโลก ด้วยเหตุผลเหล่านี้ WRED จึงเป็นประโยชน์ในส่วนติดต่อขาออกใด ๆ ที่คุณคาดว่าจะเกิดความแออัด อย่างไรก็ตาม WRED มักใช้ในเราเตอร์หลักของเครือข่ายมากกว่าที่ขอบของเครือข่าย เราเตอร์ Edge กำหนดลำดับความสำคัญ IP ให้กับแพ็กเก็ตขณะที่พวกเขาเข้าสู่เครือข่าย WRED ใช้ลำดับความสำคัญดังกล่าวเพื่อกำหนดวิธีการจัดการการรับส่งข้อมูลประเภทต่างๆ WRED มีเกณฑ์และน้ำหนักที่แยกต่างหากสำหรับลำดับความสำคัญของ IP ที่ต่างกันซึ่งทำให้คุณสามารถให้บริการที่แตกต่างกันในแง่ของการลดแพ็คเก็ตสำหรับประเภทการรับส่งข้อมูลที่แตกต่างกัน อัตราการเข้าชมแบบมาตรฐานอาจลดลงได้บ่อยกว่าอัตราการเข้าชมแบบพิเศษในช่วงที่เกิดภาวะความแออัด WRED ยังเป็น RSVP-aware และสามารถให้บริการ QoS แบบควบคุมได้สำหรับบริการแบบครบวงจร วิธีการทำงานโดยการสุ่มวางแพ็กเก็ตก่อนที่จะมีช่วงเวลาของความแออัดสูง WRED บอกแหล่งที่มาของแพคเก็ตเพื่อลดอัตราการส่งของ ถ้าแหล่งที่มาของแพคเก็ตใช้ TCP จะลดอัตราการส่งข้อมูลจนกว่าแพ็คเก็ตทั้งหมดจะไปถึงจุดหมายปลายทางซึ่งบ่งชี้ว่าแออัดถูกล้าง WRED โดยทั่วไปลดลงแพ็คเก็ตที่เลือกขึ้นอยู่กับความสำคัญของ IP แพ็คเก็ตที่มีลำดับความสำคัญ IP สูงกว่าจะมีโอกาสน้อยกว่าแพ็กเก็ตที่มีลำดับความสำคัญต่ำกว่า ดังนั้นความสำคัญของแพ็กเก็ตจึงสูงกว่าความเป็นไปได้ที่จะส่งแพ็กเก็ต WRED ช่วยลดโอกาสของการลดลงของหางโดยการเลือกวางแพ็คเก็ตเมื่ออินเทอร์เฟซเอาต์พุตเริ่มแสดงสัญญาณของความแออัด โดยการวางแพ็คเก็ตบางช่วงต้นแทนที่จะรอจนกว่าคิวจะเต็ม WRED หลีกเลี่ยงการวางแพ็กเก็ตจำนวนมากพร้อมกันและลดโอกาสในการซิงโครไนส์ทั่วโลก ดังนั้น WRED จึงช่วยให้สายส่งสามารถใช้งานได้ตลอดเวลา นอกจากนี้ WRED ยังลดจำนวนแพ็กเก็ตจากผู้ใช้ขนาดใหญ่ลงเล็กน้อย ดังนั้นแหล่งที่มาของการเข้าชมที่สร้างการเข้าชมมากที่สุดมีแนวโน้มที่จะชะลอตัวลงกว่าแหล่งที่มาของการเข้าชมที่สร้างการเข้าชมน้อย WRED หลีกเลี่ยงปัญหาโลกาภิวัฒน์ที่เกิดขึ้นเมื่อใช้หางหลุดเป็นกลไกหลีกเลี่ยงความแออัด การซิงโครไนส์โกลบอลจะแสดงเมื่อโฮสต์ TCP หลายตัวลดอัตราการส่งข้อมูลเพื่อตอบสนองต่อการลดแพ็คเก็ตจากนั้นเพิ่มอัตราการส่งข้อมูลอีกครั้งเมื่อความแออัดลดลง WRED มีประโยชน์เฉพาะเมื่อปริมาณการเข้าชมเป็นจำนวนมากคือการรับส่งข้อมูล TCPIP ด้วย TCP แพ็คเก็ตที่ลดลงแสดงถึงความแออัดดังนั้นแหล่งที่มาของแพคเก็ตจะลดอัตราการส่งข้อมูล กับโปรโตคอลอื่น ๆ แหล่งที่มาของแพ็กเก็ตอาจไม่ตอบสนองหรืออาจส่งแพ็คเก็ตที่ถูกทิ้งซ้ำในอัตราเดียวกัน ดังนั้นการลดแพ็กเก็ตจะไม่ลดความแออัด WRED ถือว่าการเข้าชมที่ไม่ใช่ IP เป็นลำดับความสำคัญ 0 ซึ่งเป็นลำดับความสำคัญต่ำสุด ดังนั้นการเข้าชมที่ไม่ใช่ IP โดยทั่วไปมีแนวโน้มที่จะลดลงกว่าการเข้าชม IP รูปที่ 10 แสดงให้เห็นว่า WRED ทำงานอย่างไร รูปที่ 10 การตรวจหาขนาดสุ่มโดยประมาณสุ่มขนาดของแถวโดยเฉลี่ยเราเตอร์กำหนดพารามิเตอร์ที่จะใช้ในการคำนวณ WRED โดยอัตโนมัติ ขนาดคิวโดยเฉลี่ยขึ้นอยู่กับค่าเฉลี่ยก่อนหน้าและขนาดปัจจุบันของคิว สูตรคือ: โดยที่ n เป็นตัวประกอบน้ำหนักที่อธิบายได้ซึ่งเป็นค่าที่กำหนดโดยผู้ใช้ สำหรับค่าที่สูงของ n ค่าเฉลี่ยก่อนหน้านี้มีความสำคัญมากขึ้น ปัจจัยที่มีขนาดใหญ่ทำให้ยอดและความสูงต่ำลง ขนาดของคิวโดยเฉลี่ยไม่น่าจะเปลี่ยนแปลงอย่างรวดเร็วหลีกเลี่ยงการแกว่งอย่างรุนแรงในขนาด กระบวนการ WRED จะช้าลงเพื่อเริ่มวางแพ็คเก็ต แต่อาจทำให้แพ็กเก็ตลดลงต่อไปได้อีกหลังจากที่ขนาดคิวจริงลดลงต่ำกว่าเกณฑ์ขั้นต่ำ ค่าเฉลี่ยเคลื่อนที่ช้าจะรองรับการเข้าชมชั่วคราว หมายเหตุถ้าค่าของ n สูงเกินไป WRED จะไม่ตอบสนองต่อความแออัด แพ็คเก็ตจะถูกส่งหรือลดลงเช่นเดียวกับ WRED ที่ไม่มีผล สำหรับค่าต่ำสุดของ n ขนาดของแถวโดยเฉลี่ยใกล้เคียงกับขนาดคิวปัจจุบัน ค่าเฉลี่ยที่เกิดขึ้นอาจผันผวนเมื่อมีการเปลี่ยนแปลงระดับการเข้าชม ในกรณีนี้กระบวนการ WRED จะตอบสนองต่อคิวยาว เมื่อคิวอยู่ต่ำกว่าเกณฑ์ต่ำสุดกระบวนการจะหยุดวางแพ็คเก็ต ถ้าค่า n ต่ำเกินไป WRED จะตอบสนองต่อการเข้าชมการจราจรชั่วคราวและลดการเข้าชมโดยไม่จำเป็น ข้อ จำกัด คุณไม่สามารถกำหนดค่า WRED ในอินเทอร์เฟซเดียวกันกับ CQ การจัดลำดับความสำคัญ (PQ) ของ Route Switch Process (RSP) หรือการเข้าคิว (WFQ) ที่ถ่วงน้ำหนัก Distributed Randomed Early Detection Distributed Distributed WRed (DWRED) คือการใช้ WRED สำหรับโปรเซสเซอร์อเนกประสงค์ (VIP) DWRED ให้ชุดฟังก์ชันทั้งหมดสำหรับวีไอพีที่ WRED มีอยู่ในแพลตฟอร์ม Cisco IOS มาตรฐาน คุณลักษณะ DWRED ได้รับการสนับสนุนเฉพาะในเราเตอร์ Cisco 7000 series โดยใช้โปรเซสเซอร์แบบ RSP7000 และ RSP7000 และ Cisco 7500 series กับโปรเซสเซอร์อินเทอร์เฟซ VIP2-40 ขึ้นไป แนะนำให้ใช้ตัวประมวลผลอินเทอร์เฟซ VIP2-50 เมื่ออัตราการรวมของอะแดปเตอร์พอร์ตบนวีไอพีสูงกว่า DS3 จำเป็นต้องมีตัวประมวลผลอินเทอร์เฟซ VIP2-50 สำหรับอัตรา OC-3 DWRED มีการกำหนดค่าเช่นเดียวกับ WRED หากคุณเปิดใช้งาน WRED บนอินเทอร์เฟซวีไอพีที่เหมาะสมเช่น VIP2-40 ขึ้นไปและมี SRAM อย่างน้อย 2 MB จะมีการเปิดใช้ DWRED แทน ในการใช้ DWRED ต้องเปิดใช้งานการกระจาย Cisco Express Forwarding (dCEF) แบบกระจายในอินเทอร์เฟซ สำหรับข้อมูลเกี่ยวกับ dCEF โปรดดูคู่มือการกำหนดค่าบริการการกำหนดค่า Cisco IOS และคู่มืออ้างอิงการให้บริการการกำหนดค่า Cisco IOS Switching Services คุณสามารถกำหนดค่าทั้ง DWRED และแบบกระจายการจัดคิว (DWFQ) บนอินเตอร์เฟสเดียวกันได้ แต่คุณไม่สามารถกำหนดค่า WRED แบบกระจายบนอินเทอร์เฟซซึ่งมีการกำหนดค่า CQ, PQ หรือ WFQ ที่ใช้ RSP คุณสามารถเปิดใช้งาน DWRED ได้โดยใช้คุณลักษณะ Modular Quality of Service Interface (Modular QoS CLI) สำหรับข้อมูลแนวคิดและข้อมูลคอนฟิกูเรชันทั้งหมดเกี่ยวกับคุณลักษณะ Modular QoS CLI ให้ดูที่บทบทบรรยายท้ายเกี่ยวกับคุณภาพของบริการ Command-Line Interface ของหนังสือเล่มนี้ วิธีการทำงานเมื่อแพคเก็ตมาถึงและ DWRED ถูกเปิดใช้งานเหตุการณ์ต่อไปนี้เกิดขึ้น: คำนวณขนาดคิวโดยเฉลี่ย ดูส่วน quantquot quotability ของรายละเอียดสำหรับรายละเอียด ถ้าค่าเฉลี่ยน้อยกว่าเกณฑ์ขั้นต่ำของคิวการรับส่งข้อมูลที่กำลังเดินทางเข้าคิวจะถูกจัดคิว ถ้าค่าเฉลี่ยอยู่ระหว่างเกณฑ์ขั้นต่ำของคิวและเกณฑ์การจัดคิวสูงสุดแพคเก็ตจะถูกลดหรือจัดคิวขึ้นอยู่กับความน่าจะเป็นของการวางแพคเก็ต ดูรายละเอียดในส่วน quotPacket-Drop Probabilityquot ถ้าขนาดคิวโดยเฉลี่ยสูงกว่าเกณฑ์ของคิวสูงสุดแพคเก็ตจะลดลงโดยอัตโนมัติ ขนาดคิวโดยเฉลี่ยขนาดคิวโดยเฉลี่ยขึ้นอยู่กับค่าเฉลี่ยก่อนหน้าและขนาดปัจจุบันของคิว สูตรคือ: โดยที่ n เป็นตัวประกอบน้ำหนักที่อธิบายได้ซึ่งเป็นค่าที่กำหนดโดยผู้ใช้ สำหรับค่าที่สูงของ n ขนาดคิวเฉลี่ยก่อนหน้านี้มีความสำคัญมากขึ้น ปัจจัยที่มีขนาดใหญ่ทำให้ยอดและความสูงต่ำลง ขนาดของคิวโดยเฉลี่ยไม่น่าจะเปลี่ยนแปลงอย่างรวดเร็วหลีกเลี่ยงการแกว่งอย่างรุนแรงในขนาด กระบวนการ WRED จะช้าลงเพื่อเริ่มวางแพ็คเก็ต แต่อาจทำให้แพ็กเก็ตลดลงต่อไปได้อีกหลังจากที่ขนาดคิวจริงลดลงต่ำกว่าเกณฑ์ขั้นต่ำ ค่าเฉลี่ยเคลื่อนที่ช้าจะรองรับการเข้าชมชั่วคราว หมายเหตุถ้าค่าของ n สูงเกินไป WRED จะไม่ตอบสนองต่อความแออัด แพ็คเก็ตจะถูกส่งหรือลดลงเช่นเดียวกับ WRED ที่ไม่มีผล สำหรับค่าต่ำสุดของ n ขนาดของแถวโดยเฉลี่ยใกล้เคียงกับขนาดคิวปัจจุบัน ค่าเฉลี่ยที่เกิดขึ้นอาจผันผวนเมื่อมีการเปลี่ยนแปลงระดับการเข้าชม ในกรณีนี้กระบวนการ WRED จะตอบสนองต่อคิวยาว เมื่อคิวอยู่ต่ำกว่าเกณฑ์ต่ำสุดกระบวนการจะหยุดวางแพ็คเก็ต ถ้าค่า n ต่ำเกินไป WRED จะตอบสนองต่อการเข้าชมการจราจรชั่วคราวและลดการเข้าชมโดยไม่จำเป็น ความน่าจะเป็น Packet-Drop ความน่าจะเป็นที่แพ็กเก็ตจะลดลงจะขึ้นอยู่กับเกณฑ์ต่ำสุดเกณฑ์สูงสุดและเครื่องหมายความน่าจะเป็นเครื่องหมาย เมื่อขนาดคิวโดยเฉลี่ยอยู่เหนือขีดต่ำสุด RED จะเริ่มวางแพ็คเก็ต อัตราการลดลงของแพ็คเก็ตจะเพิ่มขึ้นเป็นเชิงเส้นเนื่องจากขนาดของคิวโดยเฉลี่ยจะเพิ่มขึ้นจนกว่าขนาดของคิวเฉลี่ยจะถึงเกณฑ์สูงสุด เครื่องหมายความเป็นไปได้คือเศษของแพ็คเก็ตที่ลดลงเมื่อขนาดคิวโดยเฉลี่ยอยู่ที่เกณฑ์สูงสุด ตัวอย่างเช่นถ้าตัวหารเป็น 512 หนึ่งในทุก 512 แพ็คเก็ตจะลดลงเมื่อคิวเฉลี่ยอยู่ที่เกณฑ์สูงสุด เมื่อขนาดคิวโดยเฉลี่ยสูงกว่าเกณฑ์สูงสุดแพ็คเก็ตทั้งหมดจะถูกลดลง รูปที่ 11 สรุปความน่าจะเป็นของ packet drop รูปที่ 11 ความน่าจะเป็น Packet Drop Probability ค่า threshold ต่ำสุดควรตั้งค่าให้สูงพอที่จะเพิ่มการใช้งาน Link ถ้าค่าต่ำสุดต่ำเกินไปแพ็กเก็ตอาจถูกลดลงโดยไม่จำเป็นและไม่สามารถใช้การเชื่อมโยงการส่งข้อมูลได้อย่างเต็มที่ ความแตกต่างระหว่างเกณฑ์สูงสุดและเกณฑ์ต่ำสุดควรใหญ่พอที่จะหลีกเลี่ยงการซิงโครไนส์ของโฮสต์ TCP ทั่วโลก (การซิงโครไนส์ทั่วโลกของโฮสต์ TCP อาจเกิดขึ้นได้เนื่องจากโฮสต์ TCP จำนวนมากลดอัตราการส่ง) ถ้าความแตกต่างระหว่างเกณฑ์สูงสุดและต่ำสุดมีขนาดเล็กเกินไปแพ็คเก็ตจำนวนมากอาจถูกลดลงพร้อม ๆ กันทำให้เกิดการซิงโครไนส์ทั่วโลก ทำไมต้องใช้ DWRED DWRED ให้ประสิทธิภาพที่เร็วกว่า Rails ที่ใช้ WRED คุณควรใช้ DWRED กับวีไอพีหากต้องการบรรลุความเร็วสูงมากในแพลตฟอร์ม Cisco 7500 series เช่นคุณสามารถบรรลุความเร็วได้ที่อัตรา OC-3 โดยใช้ WRED บนตัวประมวลผลอินเทอร์เฟซ VIP2-50 นอกจากนี้เหตุผลเดียวกับที่คุณจะใช้ WRED บนแพลตฟอร์ม Cisco IOS มาตรฐานใช้กับการใช้ DWRED (ดูหัวข้อ "ทำไมต้องใช้ WREDquot ก่อนหน้าในบทนี้) ตัวอย่างเช่นเมื่อไม่ได้กำหนดค่า WRED หรือ DWRED จะมีการประกาศใช้การลดลงของหางในช่วงที่มีการแออัด การเปิดใช้งาน DWRED จะช่วยแก้ปัญหาการซิงค์ข้อมูลส่วนกลางที่เกิดขึ้นเมื่อใช้หางหางเพื่อหลีกเลี่ยงความแออัด คุณลักษณะ DWRED ให้ประโยชน์กับการเข้าชมที่สม่ำเสมอ เมื่อไม่มีการกำหนดค่า RED บัฟเฟอร์เอาต์พุตจะเติมระหว่างช่วงเวลาที่แออัด เมื่อบัฟเฟอร์เต็มตัวการลดหางจะเกิดขึ้นทุกแพ็คเก็ตเพิ่มเติมจะถูกลดลง เนื่องจากแพ็คเก็ตถูกทิ้งทั้งหมดพร้อมกันการซิงโครไนส์สากลของโฮสต์ TCP อาจเกิดขึ้นได้เนื่องจากโฮสต์ TCP หลายเครื่องลดอัตราการส่งข้อมูล ความแออัดจะลดลงและโฮสต์ TCP จะเพิ่มอัตราการส่งข้อมูลซึ่งจะส่งผลให้มีคลื่นของความแออัดตามด้วยระยะเวลาที่ไม่ได้ใช้การเชื่อมโยงการส่ง RED ช่วยลดโอกาสของการลดลงของหางโดยการเลือกวางแพ็กเก็ตเมื่ออินเทอร์เฟซเอาต์พุตเริ่มแสดงสัญญาณของความแออัด โดยการปล่อยแพ็คเก็ตบางอย่างออกก่อนแทนที่จะรอจนกว่าบัฟเฟอร์จะเต็มแดงจะหลีกเลี่ยงการวางแพ็กเก็ตจำนวนมากพร้อมกันและลดโอกาสในการซิงโครไนส์ทั่วโลก ดังนั้น RED ช่วยให้สายส่งสามารถใช้งานได้ตลอดเวลา นอกจากนี้ RED ยังลดจำนวนแพ็กเก็ตจากผู้ใช้ขนาดใหญ่ลงเล็กน้อย ดังนั้นแหล่งที่มาของการเข้าชมที่สร้างการเข้าชมมากที่สุดมีแนวโน้มที่จะชะลอตัวลงกว่าแหล่งที่มาของการเข้าชมที่สร้างการเข้าชมน้อย DWRED มีเกณฑ์และน้ำหนักที่แยกต่างหากสำหรับลำดับความสำคัญของ IP ที่ต่างกันทำให้คุณสามารถให้บริการที่แตกต่างกันสำหรับการเข้าชมที่แตกต่างกัน อัตราการเข้าชมแบบมาตรฐานอาจลดลงได้บ่อยกว่าอัตราการเข้าชมแบบพิเศษในช่วงที่เกิดภาวะความแออัด ข้อ จำกัด ข้อ จำกัด ต่อไปนี้ใช้กับคุณลักษณะ DWRED: ไม่สามารถกำหนดค่า DWRED แบบอินเทอร์เฟซบน subinterface (subinterface เป็นหนึ่งในอินเทอร์เฟซเสมือนบนอินเทอร์เฟซทางกายภาพเดียว) DWRED ไม่ได้รับการสนับสนุนบน Fast EtherChangel และอินเทอร์เฟซอุโมงค์ RSVP ไม่ได้รับการสนับสนุนใน DWRED DWRED มีประโยชน์เฉพาะเมื่อปริมาณการเข้าชมเป็นจำนวนมากเท่านั้นคือการรับส่งข้อมูล TCPIP ด้วย TCP แพ็คเก็ตที่ลดลงแสดงถึงความแออัดดังนั้นแหล่งที่มาของแพคเก็ตลดอัตราการส่งข้อมูล กับโปรโตคอลอื่น ๆ แหล่งที่มาของแพ็กเก็ตอาจไม่ตอบสนองหรืออาจส่งแพ็คเก็ตที่ถูกทิ้งซ้ำในอัตราเดียวกัน ดังนั้นการลดแพ็กเก็ตไม่จำเป็นต้องลดความแออัด DWRED ถือว่าการเข้าชมที่ไม่ใช่ IP เป็นลำดับความสำคัญ 0 ซึ่งเป็นลำดับความสำคัญต่ำสุด ดังนั้นการเข้าชมที่ไม่ใช่ IP มักจะมีแนวโน้มลดลงกว่าการเข้าชม IP ไม่สามารถกำหนดค่า DWRED บนอินเทอร์เฟซเดียวกับ CQ, PQ หรือ WFQ ที่อิงกับ RSP อย่างไรก็ตามทั้ง DWRED และ DWFQ สามารถกำหนดค่าได้บนอินเทอร์เฟซเดียวกัน หมายเหตุอย่าใช้คำสั่งของโปรโตคอล match เพื่อสร้างคลาสการรับส่งข้อมูลที่มีโปรโตคอลที่ไม่ใช่ IP เป็นเกณฑ์การจับคู่ วีไอพีไม่สนับสนุนการจับคู่โปรโตคอลที่ไม่ใช่ IP ข้อกำหนดเบื้องต้นในส่วนนี้จะให้ข้อกำหนดเบื้องต้นที่ต้องทำก่อนที่คุณจะกำหนดค่าคุณลักษณะ DWRED การจัดคิวอย่างเป็นประโยชน์ (Weighted Fair Queuing) การแนบนโยบายบริการกับอินเทอร์เฟซจะปิดการใช้งาน WFQ บนอินเทอร์เฟซนั้นถ้า WFQ ถูกกำหนดค่าสำหรับอินเทอร์เฟซ ด้วยเหตุนี้คุณควรตรวจสอบให้แน่ใจว่า WFQ ไม่ได้เปิดใช้งานบนอินเทอร์เฟซดังกล่าวก่อนกำหนดค่า DWRED การแนบนโยบายบริการที่กำหนดค่าให้ใช้ WRED กับอินเทอร์เฟซจะปิดใช้งาน WRED ในอินเทอร์เฟซดังกล่าว ถ้าชั้นการเข้าชมที่คุณกำหนดค่าในแผนที่นโยบายใช้ WRED สำหรับการวางแพ็คเก็ตแทนการลดหางคุณต้องตรวจสอบว่า WRED ไม่ได้รับการกำหนดค่าบนอินเทอร์เฟซที่คุณต้องการแนบนโยบายการบริการนั้น รายการควบคุมการเข้าถึงคุณสามารถระบุรายการการเข้าถึงที่มีหมายเลขเป็นเกณฑ์การจับคู่สำหรับคลาสการรับส่งข้อมูลที่คุณสร้างขึ้น ด้วยเหตุนี้ก่อนที่จะกำหนดค่า DWRED คุณควรรู้วิธีตั้งค่ารายการเข้าถึง Cisco Express Forwarding เพื่อที่จะใช้ DWRED ต้องเปิดใช้งานการสลับ dCEF บนอินเทอร์เฟซ สำหรับข้อมูลเกี่ยวกับ dCEF โปรดดูคู่มือการตั้งค่าคอนฟิก Cisco IOS Switching Services WRED Flow-Based WRED ใช้ Flow-Based WRED เป็นคุณลักษณะที่บังคับให้ WRED ให้ความเป็นธรรมแก่การไหลทั้งหมดบนอินเทอร์เฟซสำหรับแพ็คเก็ตที่ลดลง ทำไมต้องใช้ WRED แบบใช้โฟลว์ก่อนที่คุณจะพิจารณาถึงข้อได้เปรียบที่ใช้ข้อเสนอ WRED แบบไหลช่วยให้คิดว่า WRED (โดยไม่มีการกำหนดค่า WRED แบบไหล) มีผลต่อการไหลของแพคเก็ตแบบต่างๆ แม้กระทั่งก่อนที่ WRED ที่ใช้การไหลเวียนของแพคเก็ตจะแบ่งประเภทการไหลของแพ็กเก็ตการไหลอาจถือได้ว่าเป็นไปตามประเภทใดประเภทหนึ่งดังต่อไปนี้ Nonadaptive flows ซึ่งเป็นกระแสที่ไม่ตอบสนองต่อความแออัด กระแสที่มีประสิทธิภาพซึ่งโดยเฉลี่ยจะมีอัตราข้อมูลสม่ำเสมอและชะลอตัวลงเพื่อตอบสนองต่อความแออัด กระแสที่เปราะบางซึ่งแม้ว่าความแออัดจะมีแพ็คเก็ตน้อยลงที่มีเกตเวย์มากกว่าจะมีประสิทธิภาพ WRED มีแนวโน้มที่จะสร้างความลำเอียงกับกระแสที่บอบบางเพราะกระแสทั้งหมดแม้แต่ที่มีแพ็คเก็ตค่อนข้างน้อยในคิวการส่งออกจะอ่อนแอต่อการลดลงของแพคเก็ตในช่วงที่มีการแออัด แม้ว่ากระแสข้อมูลที่เปราะบางมีแพ็คเก็ตบัฟเฟอร์น้อยกว่า แต่จะลดลงในอัตราเดียวกับแพ็คเก็ตของกระแสอื่น ๆ เพื่อให้ความเป็นธรรมกับทุกกระแสไหล WRED มีคุณสมบัติดังต่อไปนี้เพื่อให้แน่ใจว่ากระแสที่ตอบสนองต่อการลดลงของแพ็คเก็ต WRED (โดยการปิดการส่งแพ็กเก็ต) จะได้รับการป้องกันจากกระแสข้อมูลที่ไม่ตอบสนองต่อการห่อแพ็กเก็ต WRED ห้ามไหลเดี่ยวจากการผูกขาดแหล่งข้อมูลบัฟเฟอร์ที่อินเทอร์เฟซ วิธีการทำงาน WRED แบบอิงกระแส (Flow-based WRED) อาศัยแนวทางต่อไปนี้สองแนวทางหลักในการแก้ไขปัญหาการลดลงของแพคเก็ตที่ไม่เป็นธรรม: แบ่งประเภทการรับส่งข้อมูลเข้าสู่กระแสข้อมูลโดยอิงตามพารามิเตอร์เช่นปลายทางและที่อยู่ต้นทางและพอร์ต จะรักษาสถานะเกี่ยวกับกระแสที่ใช้งานซึ่งเป็นกระแสที่มีแพ็กเก็ตในคิวการส่งออก WRED แบบใช้ข้อมูลการใช้ข้อมูลการจำแนกประเภทนี้และข้อมูลสถานะเพื่อให้มั่นใจว่าการไหลแต่ละครั้งไม่ได้กินมากกว่าที่ได้รับอนุญาตจากแหล่งข้อมูลบัฟเฟอร์เอาต์พุต WRED แบบไหลตามกำหนดว่ากระแสใดจะผูกขาดทรัพยากรและจะลงโทษกระแสเหล่านี้อย่างมากยิ่งขึ้น เพื่อให้แน่ใจว่าความเป็นธรรมระหว่างกระแสไหลตาม WRED รักษาจำนวนของกระแสงานที่มีอยู่ผ่านอินเตอร์เฟสเอาท์พุท เมื่อพิจารณาถึงจำนวนของการไหลที่ใช้งานและขนาดคิวการส่งออก WRED แบบไหลตามกำหนดจำนวนบัฟเฟอร์ที่มีต่อการไหล เพื่อให้สามารถเกิดความเบื่อหน่ายได้ WRED แบบใช้คลื่นช่วยเพิ่มจำนวนบัฟเฟอร์ที่มีต่อการไหลโดยใช้แฟคเตอร์ที่กำหนดค่าไว้และช่วยให้การไหลเวียนแต่ละครั้งมีจำนวนแพ็คเก็ตที่แน่นอนในคิวเอาท์พุท ปัจจัยการปรับขนาดนี้เป็นไปตามกระแสทั้งหมด ผลลัพธ์ของจำนวนที่ปรับขนาดของบัฟเฟอร์จะกลายเป็นขีด จำกัด ต่อการไหล เมื่อการไหลเกินขีด จำกัด ต่อการไหลความน่าจะเป็นที่แพ็กเก็ตจากการไหลนั้นจะลดลง DiffServ มาตรฐาน WRED DiffServ ตามมาตรฐาน WRED ขยายการทำงานของ WRED เพื่อให้สามารถรองรับ DiffServ และ AF ต่อ Hop Behavior PHB คุณลักษณะนี้ช่วยให้ลูกค้าสามารถใช้ AF PHB โดยการทำสีแพ็คเก็ตตามค่า DSCP และกำหนดความน่าจะเป็นที่ต้องการให้กับแพคเก็ตเหล่านั้น หมายเหตุคุณลักษณะนี้สามารถใช้กับแพคเก็ต IP เท่านั้น ไม่ได้มีไว้สำหรับใช้กับ Multiprotocol Label Switching (MPLS) - แพคเก็ตที่มีแคปซูล คุณภาพการให้บริการของ Class MIB สนับสนุนคุณลักษณะนี้ MIB นี้เป็นสอง MIB ต่อไปนี้: คุณลักษณะ WRED ที่สอดคล้องกับ DiffServ สนับสนุน RFCs ต่อไปนี้: RFC 2474 ความหมายของฟิลด์บริการที่แตกต่าง (DS Field) ในส่วนหัว IPv4 และ IPv6 RFC 2475 สถาปัตยกรรมสำหรับเฟรมบริการที่แตกต่างกัน RFC 2597, การส่งต่อที่แน่นอน PHB RFC 2598, การส่งต่อเร่งด่วน PHB วิธีการทำงานคุณลักษณะ WRED ที่สอดคล้องกับ DiffServ ช่วยให้ WRED สามารถใช้ค่า DSCP เมื่อคำนวณความน่าจะลดลงของแพ็คเก็ต ค่า DSCP คือหกบิตแรกของประเภทไบต์บริการ (ToS) IP คุณลักษณะนี้เพิ่มคำสั่งใหม่ 2 คำสั่งคือ dscp และ dscp แบบสุ่ม นอกจากนี้ยังเพิ่มอาร์กิวเมนต์ใหม่สองรายการ ได้แก่ dscp และ prec-based ไปยังคำสั่งที่เกี่ยวกับ WRED สองคำสั่งที่เกี่ยวข้องกับคำสั่ง random-detect (interface) และคำสั่ง random-detect-group อาร์กิวเมนต์ที่ใช้ dscp ช่วยให้ WRED สามารถใช้ค่า DSCP ของแพ็คเก็ตเมื่อคำนวณความน่าจะลดลงของแพ็กเก็ต อาร์กิวเมนต์ prec-based ช่วยให้ WRED ใช้ค่า Precedence IP ของแพ็คเก็ตเมื่อคำนวณความน่าจะลดลงของแพ็คเก็ต อาร์กิวเมนต์เหล่านี้เป็นตัวเลือก (คุณไม่จำเป็นต้องใช้คำสั่งใด ๆ ในการใช้คำสั่ง) แต่ก็เป็นข้อยกเว้นกัน นั่นคือถ้าคุณใช้อาร์กิวเมนต์ที่ใช้ dscp คุณไม่สามารถใช้อาร์กิวเมนต์ที่ใช้ prec โดยใช้คำสั่งเดียวกัน หลังจากเปิดใช้งาน WRED เพื่อใช้ค่า DSCP แล้วคุณสามารถใช้คำสั่ง dscp แบบสุ่มใหม่เพื่อแก้ไขค่าต่ำสุดและสูงสุดของแพ็คเก็ตสำหรับค่า DSCP นั้น มีการใช้สถานการณ์สมมติสามข้อในการใช้อาร์กิวเมนต์เหล่านี้ Usage Scenarios The new dscp-based and prec-based arguments can be used whether you are using WRED at the interface level, at the per-virtual circuit (VC) level, or at the class level (as part of class-based WFQ (CBWFQ) with policy maps). WRED at the Interface Level At the interface level, if you want to have WRED use the DSCP value when it calculates the drop probability, you can use the dscp-based argument with the random-detect (interface) command to specify the DSCP value. Then use the random-detect dscp command to specify the minimum and maximum thresholds for the DSCP value. WRED at the per-VC Level At the per-VC level, if you want to have WRED use the DSCP value when it calculates the drop probability, you can use the dscp-based argument with the random-detect-group command. Then use the dscp command to specify the minimum and maximum thresholds for the DSCP value or the mark-probability denominator. This configuration can then be applied to each VC in the network. WRED at the Class Level If you are using WRED at the class level (with CBWFQ), the dscp-based and prec-based arguments can be used within the policy map. First, specify the policy map, the class, and the bandwidth. Then, if you want WRED to use the DSCP value when it calculates the drop probability, use the dscp-based argument with the random-detect (interface) command to specify the DSCP value. Then use the random-detect dscp command to modify the default minimum and maximum thresholds for the DSCP value. This configuration can then be applied wherever policy maps are attached (for example, at the interface level, the per-VC level, or the shaper level). Usage Points to Note Remember the following points when using the new commands and the new arguments included with this feature: If you use the dscp-based argument, WRED will use the DSCP value to calculate the drop probability. If you use the prec-based argument, WRED will use the IP Precedence value to calculate the drop probability. The dscp-based and prec-based arguments are mutually exclusive. If you do not specify either argument, WRED will use the IP Precedence value to calculate the drop probability (the default method). The random-detect dscp command must be used in conjunction with the random-detect (interface) command. The random-detect dscp command can only be used if you use the dscp-based argument with the random-detect (interface) command. The dscp command must be used in conjunction with the random-detect-group command. The dscp command can only be used if you use the dscp-based argument with the random-detect-group command. For more information about using these commands, refer to the Cisco IOS Quality of Service Command Reference.New Jersey Department of Transportation Traffic Mitigation Guidelines The Department is committed to providing a network of transportation facilities that enables New Jersey residents, workers, and visitors to move efficiently within and through the State. Developing and maintaining a Statewide transportation network requires that the Department periodically upgrade and improve these facilities through construction projects. The Departments first priority is to complete these projects in a timely and cost-efficient manner. The Department recognizes, however, that construction projects inconvenience motorists traveling through the construction corridors and disrupt businesses located nearby, in some cases resulting in substantial user costs. The safe and efficient flow of vehicles, pedestrians, and bicyclists through roadway construction areas has long been a concern to the Department for its impact on construction operations. Its importance has intensified as motorists, frustrated with the normal levels of congestion they face on ordinary days, have begun to complain about the inconvenience and costs of additional delays caused by roadway reconstruction activities. In addition, businesses complain that nearby construction activities negatively affect their operations and sales. Traffic mitigation (TM) strategies offer benefits to the public, the Department, and other State and local agencies involved in construction projects. TM strategies can improve the flow of traffic through the construction area and along detour routes, minimizing the disruption to motorists and businesses. TM strategies can educate the public about the purpose of and plans for construction projects, helping to reduce citizen complaints and build goodwill for the Department. TM strategies also can encourage motorists to use transit and other alternate modes and educate travelers about the benefits of these modes. Some strategies support efficient and timely completion of construction projects, offering cost savings to the Department and minimizing the duration of disruption for motorists. Finally, TM strategies can reduce the number of incidents in construction corridors via speed incident detection and emergency response to reopen the route. The Department has an interest in realizing traffic mitigation benefits for both itself and the traveling public whenever it is feasible and cost-effective to do so. However, it is difficult to eliminate all construction-related disruption. These Traffic Mitigation Guidelines help provide a customer-oriented approach to the implementation of roadway improvements. These Traffic Mitigation Guidelines were developed following a three-step research process. First, individual and group meetings and interviews were conducted with staff of divisions with an interest or potential role in TM activities, including, but not limited to: Division of Project Management Division of Project Planning and Development Bureau of Traffic Operations Bureau of Traffic Engineering Bureau of Statewide Planning Bureau of Capital Program Support Office of Communications Office of Community Relations NJ Transit The purpose of these meetings was to explore the TM needs of the divisions, identify their existing TM responsibilities and approaches, identify any proposed efforts by the divisions to expand TM activities or improve TM planning, discuss opportunities to address TM within the current project development process, and identify other processes that would increase the visibility of TM in project development. Second, the CPM Procedures Manual and other existing internal documents were reviewed to identify existing application of TM and possible additions that could facilitate more comprehensive consideration and application of TM. Third, the experience of other state transportation departments with TM planning and implementation was reviewed. Following the meetings and review of documents, all divisions agreed that additional written TM guidelines could be useful to the divisions involved in these activities by establishing a formal procedure for integrating TM into project development and serving as a single source summary for how traffic mitigation is considered at each stage of the project planning process. It was agreed that it would be appropriate to prepare a stand-alone TM procedures document that would supplement the CPM Procedures Manual. The guidance would be distributed to all the divisions that have a role or interest in traffic mitigation as an overall framework for integrating traffic mitigation with existing project development activities. It is expected that individual divisions, offices, and bureaus will develop additional instructions to guide their staff in the proper application of TM procedures and responsibilities established for their units. Additionally, it is anticipated that the information in this document would be referenced in the CPM Procedures Manual and addressed in tools used in the project development process, such as Quality Assurance Checklists, Project Scoping Checklists, Quality Assurance and Constructability reviews, Constructability Checklists, and Construction Progress Schedules. This document presents guidance for consistent and comprehensive consideration of traffic mitigation strategies for roadway reconstruction projects implemented by the Department. The objectives of the Traffic Mitigation Policy and Procedures and Guidelines are to: Balance the Departments need to minimize roadway construction costs with the need to minimize construction-related inconvenience for motorists and other stakeholders Ensure that traffic mitigation needs are addressed systematically and consistently in all projects Provide adequate lead-time for Departmental staff and outside partners charged with implementing traffic mitigation strategies to prepare for their responsibilities Maintain high visibility for TM throughout project planning and design Ensure that funding for traffic mitigation is considered early in the planning process and is programmed with design and construction monies Clarify roles and responsibilities for TM These objectives will be accomplished through the implementation of a formal procedure for considering TM needs and options. This procedure will include the following activities, which are defined further in later sections of this document: During Concept Development, identify projects needing TM and the specific TM challenges of those projects In Feasibility Assessment, define an appropriate level of TM needed for each project, based on the expected impacts to road users and businesses, in terms of the expected delay during construction and other factors In Preliminary Design, select and document a set of TM strategies that are likely to meet traffic mitigation goals within TM cost guidelines established for the project Develop a draft TM implementation plan for the project Refine the initial set of TM strategies and the implementation plan as the project becomes more clearly defined through Final Design Finalize the TM plan as design nears completion Implement and evaluate the TM plan The steps outlined above will involve many NJDOT units and outside parties whose expertise is needed or is beneficial for t he development and implementation of TM programs. Traffic mitigation can be multi-faceted, multi-disciplinary, and multi-jurisdictional. These guidelines account for the fact that there is a complex interaction of strategies and partners and provide for coordination and communication among internal and external parties. The balance of this document is divided into five major sections following this introduction: Section 2: Analysis of Need for Traffic Mitigation Describes a process to assess the level of TM needed for a project and estimate order of magnitude costs for TM Section 3: Guidelines for Selecting Traffic Mitigation Strategies Presents a menu of TM strategies and indicates strategies that are appropriate and indicated for various project characteristics. Section 4 : Integration of Traffic Mitigation Within the Existing Project Development Process Describes the approach to integrating TM within project development Section 5: Traffic Mitigation Documentation Describes components of and responsibilities for various TM documents Section 6: Monitoring and Evaluation Presents suggested evaluation measures and procedures for monitoring and evaluating the effectiveness of TM activities Section 7: State-Level Procedures Presents procedures that were created in response to the FHWA Work Zone Rule that identifies three strategic components: Policy, State-Level Procedures, and Project-Level Procedures. Section 8: Project-Level Procedures Presents procedures that were created in response to the FHWA Work Zone Rule that identifies three strategic components: Policy, State-Level Procedures, and Project-Level Procedures. Section 9: Additional Resources Presents websites providing examples and fact sheets. Appendix A: Work Zone Safety and Mobility Policy Presents policy created in response to the FHWA Work Zone Rule. Traffic mitigation decisions are, by necessity, made on a case-by case basis. Each project is unique. The extent and types of traffic mitigation strategies selected for a project will be determined by the characteristics of the project and the site in which it will be located. Additionally, some projects offer special traffic mitigation challenges and some strategies will be better able than others to accomplish these needs. Some projects cause little disruption to motorists and will need nothing more than modest signage to inform motorists that construction is ahead. Other projects, especially those for which substantial travel delays are expected, might require numerous TM strategies, including strategies that divert traffic to alternate routes, provide new travel options, inform a wide audience of travelers about the construction, or alter construction procedures. This section describes the types of project characteristics that can influence TM decisions and offers guidance on how to determine the general level of TM needed for a project and to estimate an order-of-magnitude TM cost. Following this section, guidance is presented for choosing individual TM strategies. The number and mix of strategies included in a traffic mitigation program will depend on many factors, including the scope and duration of the project, the volume of traffic currently using the roadway, characteristics of the construction site, the construction activities that must be accomplished, and the travel alternatives available to motorists. A package of strategies must be chosen that will address the specific challenges for that project. Many project characteristics could influence the need for traffic mitigation and the extent and type of traffic mitigation strategies chosen. Several characteristics are considered to be especially important. These include characteristics related to the level and type of impacts the project is likely to cause to motorists and to members of the community in which the project is located. These primary characteristics should be examined early in the TM process Road User Cost of Staging Impacts to retail business Impacts to neighborhoods Impact on military and emergency response Impacts on access to major activity centers or employers Impacts on localdeveloper projects Constructability Political sensitivity Other characteristics have a less direct relationship to TM but also might be useful to examine to help identify specific TM strategies that could be useful to implement. These secondary characteristics include the following: Duration of construction (months) Number of major construction stages Lane and ramp closures Type of roadway Interstate, State, major arterial Average daily traffic (ADT) volume Seasonal recreational traffic volume increase Expected delay (vehicle hours per day) or queue length (miles) Distance covered by the project Level of urbanization in the construction area Proportion of trucks in the traffic mix Extent of publicmedia exposure Nearby projects influence and impact Maintenance considerations Holidays and schools Road user cost (RUC) is an economic measure of the impact of construction on motorists. It is calculated as the added vehicle operating costs and delay costs borne by highway users as a result of construction projects. These costs are a function of the timing, duration, scope, and characteristics of the construction project, and the volume and operating characteristics of the traffic affected. Road user cost is important in TM because it helps to define an appropriate expenditure for TM activities. A high RUC suggests a greater investment should be made in TM. But RUC also sets an upper limit for the TM investment. In general, the total cost of TM should not exceed the total RUC. 2.3.1 Impacts to Retail Businesses Some construction projects will have a direct impact on retail businesses because they may make the businesses inaccessible, reduce parking areas, or divert traffic away from the businesss locations. Roadway signage can be used to promote these businesses and indicate how they can be accessed. Construction strategies and some traffic control and operations strategies need to be particularly well-planned when businesses are affected, but strategies that reduce the duration of construction could be very appropriate. 2.3.2 Impacts to Neighborhoods Construction projects also can create significant problems for residents in neighborhoods near the construction area. As for business, construction can hinder access and reduce parking. Construction strategies and some traffic control and operations strategies that minimize the flow of traffic through the area andor reduce the duration of construction could be very appropriate. 2.3.3 Impacts on Military and Emergency Response Construction projects can disrupt the ability to respond to emergencies. This should be considered when developing traffic staging plans, temporary detours, or changing access to residential and business areas. 2.3.4 Impacts on Access to Major Activity Centers or Employers Construction areas that pass through or near major activity centers or employment areas can create substantial traffic back-ups, especially at peak travel times. Generally, the more commercial centers and employers are affected by construction, the more TM planning should emphasize public information, construction strategies, alternate routes, and Travel Demand Management (TDM). TDM strategies, such as rideshare incentives, transit improvements, and Park amp Ride lots should receive emphasis when they can be targeted to major employment centers. 2.3.5 Constructability Key characteristic which must be considered early on is the ability to construct a project in the manner envisioned. Soliciting input early on from individuals with construction expertise and the ability to consider abstract ideas in three dimensions are necessary to ensure that the project can be built as planned. 2.3.6 Political Sensitivity Projects with high political sensitivity include those in which lawsuits are underway or threatened, or where political leaders and interest groups are taking highly visible positions either for or against the project. These projects require special emphasis on public information and motorist information. They also might require attention to alternate routes and lane and ramp closures proposed for the construction. Additionally, legislative offices should be kept informed of project progress through legislative liaisons and fax networks. 2.4.1 Duration of Construction (months) The length of time construction is expected to last has a significant impact on both the extent of TM and the types of strategies chosen. Long projects generally can need and can justify a greater number of strategies and more aggressive strategies than can short-duration projects. Although capital improvements might be justified if they provide permanent improvements, large scale and capital intensive strategies are generally used only for large projects. 2.4.2 Number of Major Construction Stages A multi-staged project can create frequent changes in the availability of and accessibility to the roadway, leading to motorist confusion. This suggests a greater emphasis on public and motorist information about scheduled lane and ramp closures. Multi-stage projects also might be appropriate for construction strategies, alternate route, and TDM strategies. 2.4.3 Lane and Ramp Closures The need to close lanes or ramps can increase construction delay significantly. The greater the loss of capacity, the more TM will be needed. In these cases, strong consideration should be given to detours, incident management, and motorist information. Public information about the closures also should be considered to give motorists advance notice of the changes. 2.4.4 Type of Roadway Interstates and State expressways typically warrant more extensive TM than do other roads because of their high traffic volume and critical function in the roadway network. The need to complete construction quickly while maintaining traffic flow suggests strategies that reduce the duration of construction as well as incident management strategies. Because more of the traffic on these roads comes from beyond local areas, motorist information also is likely to be important. 2.4.5 Average Daily Traffic Volume The traffic volume (24 hour7 day) through the corridor has an important influence on the level of TM needed. In general, the higher the volume, the more motorists affected, the greater the total cost of delay, and the greater the justification for TM investment. High volumes suggest the use of incident management, TDM, detours, and public information strategies. 2.4.6 Seasonal Traffic Volume Increase Some highways experience significant increases in travel during certain seasonal recreational periods. If construction is scheduled on these roads during seasonally high volume times, more extensive traffic mitigation strategies could be required than during the lower volume time period. 2.4.7 Expected Delay (vehicle hours per day and per project duration) or Queue Length (miles) Delay is a significant TM characteristic because it is a key measure of the degree of disruption to motorists. Experience suggests that some of the least costly TM strategies for reducing delay over the project period include incident management and contract incentivedisincentive strategies. 2.4.8 Project Distance (miles) The length or breadth of the project can influence the types of traffic mitigation strategies chosen. Projects that extend over a large geographic area might warrant the use of detours and broad-based public information. 2.4 9 Level of Urbanization The level of urbanization frequently is related to the ADT for the roadway. Projects in highly urban areas generally warrant higher levels of TM than do projects in suburban or rural areas and offer opportunities to implement broad-based public information, such as radio ads this outreach is effective because the proportion of traffic that is local is usually high, and motorists can be reached relatively easily with print and electronic media. TDM strategies, such as additional transit and Park amp Ride lots, also are more likely to be useful in urban areas where population densities are greater. 2.4.10 Significant Truck Volume Projects with significant truck volumes can increase the need for TM because they increase vehicle delay. Where truck traffic will be heavy, attention should be focused on construction and detour strategies to divert trucks and on incident management strategies that have the capacity to handle large trucks and load spills. The volume of trucks also can affect the use of and selection of alternate routes. 2.4.11 Public and Media Attention Some projects will attract considerable public and media attention because of the project location, duration, and expected delay. These projects deserve special attention to public information, motorist information, and incident management. 2.4.12 Nearby Projects Consideration of construction planned for parallel routes or other projects in the vicinity is needed. The use of common detour routes may be problematic, so too the exponential increase in congestion caused by two projects along the same corridor. 2.4.13 Maintenance Considerations Snow removal, mowing, and other maintenance duties during construction may complicate projects and detract from the overall traffic mitigation strategy. 2.4.14 Holidays and Schools A special effort should be made to safeguard school bus routes, school crossings, and other needs of school children. Holiday shopping may impact traffic in the corridor and should be considered in the overall traffic mitigation strategy. As a general rule, the extent of expected delay and RUC will be determining factors in the requisite TM level. They are fundamental TM measures because they capture the impacts of other variables, such as the traffic volume, length of construction, and proportion of trucks in the vehicle mix. Frequently, several of the characteristics described above will appear together in a project. For example, long duration projects often are completed in stages and result in extensive cumulative delays projects on high volume roads often result in long delays roads in highly urbanized areas generally carry high traffic volumes and projects with high impacts to businessesemployment centers might be associated with political sensitivity. When multiple TM challenges exist, the level of TM likely should be elevated. In order to best assess traffic impacts, accurate and current traffic data is needed. As such, the Division of Project Planning and Development (DPPD) will acquire 24 hour weekday and weekend truckcar counts for the project area. These should include mainline volumes and, if applicable, side street volumes at signalized intersections and detour routes. Turning movements at key intersections and interchanges shall be provided for peak hour periods. This data shall either be created by, or forwarded to, the Bureau of Transportation Data Development (TDD) which shall maintain a centralized data base of all traffic volume counts. The evaluation of traffic volumes through various work zone capacities and detour routes will help the Designer understand traffic impacts associated with various lane closure alternatives. The Designer will evaluate the alternatives, on a 24 hour basis, to determine when there will be queues. Exhibit 1 shows a sample capacity versus demand chart. Exhibit 1 For evaluation of detours, the detour length and delay times shall be provided by the Designer. The NJDOT Road User Cost Manual provides greater detail in these matters. The number of lanes available in a work zone plays a significant role in the work zone capacity. Work zone capacity charts are in the NJDOT Road User Cost Manual. Basic Work Zone Staging Scenarios in the manual provide the Designer with the ability to quickly evaluate minimum width requirements for various lane closure scenarios. High impact projects are those projects that have traffic demands that exceed work zone capacities for a period of more than six hours per 24 hour day. Moderate impact projects are those projects that have traffic demands that exceed work zone capacities for a period of zero to six hours per 24 hour day. Low impact projects are those projects that have traffic demands that do not exceed work zone capacities during any time of the 24 hour day. The Department recognizes the public does not like to experience traffic delays due to construction. Therefore, the Department should include an alternative that introduces no traffic queues (i.e. volumes are less than capacity) in its evaluation matrix. Common methods to avoid queues are modifying the allowable lane closure hours and utilizing shoulder areas as temporary lanes. In the absence of accurate traffic data or in addition to the quantitative impact analysis, traffic impacts can also be assessed qualitatively. Exhibit 2 provides a worksheet that may be used as a tool to identify impact level for a particular project. It provides space to note details for the primary project characteristics and to note secondary characteristics that might be important in selecting TM strategies. The worksheet also includes a column to indicate the project level suggested by each characteristic individually and defines an overall project impact level drawn from the combination of the levels for various project characteristics. If many of the characteristics, or even a few of the primary characteristics, suggest the project has high impacts, the project likely should be classified at the higher level. Not surprisingly, as the level of impact of the project increases, the level of TM needed and its likely cost also will increase. Exhibit 2 Preliminary Traffic Mitigation Impact Worksheet Overall Impact Assessment 2.5.1 Low Impact Projects The TM needs for low impact projects generally can be adequately addressed by minimal and standard traffic controls used routinely in construction areas. These could include, for example: Fixed signs to alert motorists to the presence of construction activity ahead Traffic cones and temporary barriers to guide motorists through the construction area Low Impact TM Costs Low impact TM projects are generally assumed to have no additional costs beyond those incurred routinely for construction. 2.5.2 Moderate Impact Projects For moderate impact projects, the standard TM strategies used in low impact projects should be applied and augmented. Additional strategies that might be appropriate for these projects could include: Enhanced traffic operations and control strategies, such as construction area screening, variable message signs, reduced travel speeds, temporary parking and turn restrictions, and pavement markings Modest public outreach targeted to residents, businesses, and community centers in the local area affected by the construction: for example, postings on web sites, and fax network for employers and others Detours without additional upgrades to alternate routes Construction activity restrictionsnon-construction increases in capacity (e.g. narrow lanes) to minimize peak period delays Development of incident management plan to reduce delays caused by accidents Modest TDM strategies such as rideshare marketing Moderate Impact TM Costs Moderate impact TM projects rely primarily on strategies, such as public outreach, traffic operations and control, and TDM, which do not require construction of temporary infrastruct ure. These strategies generally have modest cost but may add 15 or more to the construction cost. 2.5.3 High Impact Projects Finally, high impact projects will receive the most aggressive TM strategies. For longer duration projects, more costly strategies could be appropriate due to the high cumulative cost of delay and disruption. Thus, for these projects, some temporary capital improvements might be warranted to maintain capacity. Additionally, it becomes more important to deliver information to the public-at-large and to motorists traveling through the construction area, and to support the needs of businesses for employees and customer access. Therefore, in addition to the strategies noted above for lesser impact projects, critical impact projects might also warrant the following: Advanced traffic operations and control strategies, such as ramp metering, signal adjustments, reversible lanes, lane closure restrictions, and truck restrictions Extensive public outreach to the public-at-large and to targeted groups, including public information meetings, brochures, news releases, media advertising, appearances at community events, a public information center, and a telephone hotline Detours that require capital improvements to alternate routes Temporary capital improvements, such as crossovers, runarounds, temporary roadways, and temporary use of shoulders and median areas to maintain capacity Contracting strategies, such as AB bidding, contractor incentivedisincentive provisions, lane rental provisions, and project consolidation Expanded TDM strategies such as temporary transit service, free bus service, Park amp Ride lots, TDM information, and assistance to employers High Impact TM Costs High impact TM projects generally implement the most aggressive levels of TM strategies. However, in many cases the construction costs for these high impact projects are also high. Therefore, the TM strategies, as a percentage of the construction cost, are typically the same or less than moderate impact projects. Section 2 presented a broad-brush approach to selecting categories of traffic mitigation (TM) strategies. The next step is to select specific strategies sufficient to meet TM goals established for the project. This section presents a menu of TM strategies and guidance for choosing effective and appropriate strategies. The primary purpose of a TM program is to maintain an acceptable level of traffic flow and minimize travel delay experienced by motorists during construction. This is accomplished by reducing the volume of traffic through the construction area, reducing the duration of construction, andor increasing the efficiency with which traffic flows through the area. Many strategies can be used to help meet these objectives. The number and mix of strategies chosen will depend on many factors, including the scope and duration of the project, the volume of traffic currently using the roadway, characteristics of the construction site, the construction activities that must be accomplished, and the travel alternatives available to motorists. A package of strategies must be chosen that will offer the maximum benefit to motorists within an acceptable cost. This section groups TM strategies into six categories, each with a different approach to TM. Individual strategies in each of these categories are described below: Construction and contracting Traffic control and operations Public information Motorist information Travel demand management (TDM) Incident management Construction and contracting strategies are strategies that can be implemented through contract documents during construction. They minimize traffic disruption by shortening the duration of construction andor by ensuring that the maximum number of travel lanes remains open at critical travel periods. Strategies in this category include: Lane constriction Two-way traffic on divided roads Lane closure restrictions Runarounds and crossovers Temporary roadway improvements Project consolidation Lane rental A B bidding IncentiveDisincentive Acceleration Value Engineering Change Proposals 3.2.1 Lane Constriction This strategy reduces the width of one or more lanes to retain a greater number of lanes available to traffic. It should be noted that narrow lane width can reduce the facilitys capacity and average speed, especially where there is significant truck traffic. The use of shoulders can help to reduce the reduction in width. If used for long-term applications, the current lane markings must be hidden and new markings applied to avoid confusing motorists. 3.2.2 Two-Way Traffic on Divided Facility This strategy transfers traffic from a normally divided facility to a two-way operation on one roadway. This strategy requires special consideration in the planning, design, and construction phases. Because of safety concerns, it should be limited to projects in which construction cannot occur without closing lanes and where alternate routes are not available for detours the use of temporary lanes or shoulders is impractical and safety issues can be reasonably addressed. 3.2.3 Lane Closure Restrictions This technique prohibits the contractor from closing lanes during certain days or hours of the day when disruption would cause particular difficulty to motorists or area businesses. If work continues beyond a deadline, a liquidated damage or disincentive payment could be deducted for each hour beyond the end time. A variation on this strategy is to allow lane closures only during nighttime hours. Additional factors should be considered before adopting this measure: noise and light impacts on surrounding communities, traffic impact of detours on surrounding communities, need for special nighttime permits, and worker safety. Nighttime work is most appropriate when traffic volumes drop substantially from day to night andor when a longer continuous period of construction activity is needed. Also, lane closures should be specific to the area of work needed. Excessive lane closure lengths should not be permitted. 3.2.4 Runarounds and Crossovers These strategies involves the total closure of a roadway in one or both directions and rerouting traffic to a temporary roadway constructed adjacent to the roadway and within the ROW or across a median of a divided highway to the opposite lanes. 3.2.5 Temporary Roadway Improvements This strategy can include measures such as temporary use of a shoulder or median area as a travel lane or temporary removal of a median island to provide additional turning lanes at critical intersections. If shoulders are to be used as travel lanes, it might be necessary to upgrade the shoulder to support anticipated traffic loads. 3.2.6 Project Consolidation This strategy promotes the consolidation of multiple, small projects planned for a single roadway or in a corridor to minimize the number of times construction activity must occur. This can be done through a single contract for all the work or individual contracts that are coordinated and scheduled together. This technique should be used during the concept developmentplanning stage, with consideration of projects proposed for completion over several years. To the extent possible, projects should be scheduled for completion within a single construction season. 3.2.7 Lane Rental Provisions This strategy has been successfully employed in other states, but as yet, there is no approved specification in New Jersey. Lane rental provisions encourage contractors to schedule work to minimize lane closure time, to work during the lowest traffic times (when rental rates are lowest), and to be more productive when lanes are closed. In the project bid, the contractor specifies the number of hours lanes will be closed. The total bid is calculated as the actual construction cost plus the number of lane closure hours multiplied by a per hour lane use charge. Fees are charged for hours when lanes are closed and are applied against a lane rental budget included in the contract. If the contractor exceeds the number of hours for lane closures included in the contract, a disincentive payment is assessed against the contractors fee. 3.2.8 A B Bidding A B bidding is a form of cost-plus-time bidding that factors the duration of a construction project into the low price bid. Contractors submit bids comprised of two components: the A component includes the traditional cost of work to be performed under the contract the B component is a bid of the total number of days the contractor estimates are required to complete the identified B portion of the project. The total bid, for award consideration only, is calculated as the A cost plus the B number of days multiplied by a road user cost per day factor. If the contractor exceeds the number of days bid, a liquidated damage is assessed for each day late. This strategy is generally reserved for major impact projects that are of long duration and have multiple-stages or for projects where traffic inconvenience and delays must be held to a minimum or where road user costs are expected to be significant due to heavy current traffic volume long project duration. 3.2.9 IncentiveDisincentive The provision of incentivesdisincentives in the contract afford the contractors the option of working more shifts in order to complete the work quickly, therefore earning an incentive payment for early completion, or of working at a slower pace, using fewer resources, forfeiting the incentive payment, and paying liquidated damages for later completion. A variable completion time may impact the overall traffic mitigation strategy and should be considered. 3.2.10 Acceleration Construction acceleration is a strategy that can be used to minimize traffic impacts by minimizing the duration of the construction impact. By identifying in the bid documents that a specific project is to be completed in a very short duration, contractors are apprised that their bid will need to consider overtime, 247 work, or whatever it takes to get the job done in the minimum time. 3.2.11 Value Engineering Change Proposals (VECP ) This program allows the contractor to offer the State alternatives to the contract documents that are equal or better and provide a cost savings or reduced traffic impacts. The purpose of traffic control and operations devices is to guide motorists clearly and safely up to, through, and around construction areas. Effective traffic control increases safety and capacity and reduces stress for drivers. Some traffic control devices, such as barriers, also play a major role in protecting workers from vehicle crashes. The choice of appropriate traffic control devices is determined by sight distances, traffic speed, volume, and the type of work activity to be performed. Traffic control and operations strategies include: Physical barriers and channelizing devices Temporary reduced speed limit Flashing arrow signs Pavement markings Construction area screening Reversible lanes Alternate routes Signal adjustments Ramp metering Temporary parking and turn restrictions Moveable barrier Truck restrictions 3.3.1 Physical Barriers and Channelizing Devices Physical barriers, such as concrete barriers, cones, and drums that separate traffic from the work area can enhance both motorist and construction crew safety. Additionally, channelizing devices can improve traffic flow by alerting motorists to construction activity ahead and giving them time to react to travel patterns changes. Special attention to snow removal should be considered when using permanent physical barriers. 3.3.2 Temporary Reduced Speed Limit Reducing the maximum allowable speed might be needed or desirable if construction activity or needed TM strategies (e.g. lane closures or lane shifting) could constitute a hazard for motorists. A reduced speed might also be desirable if the normal maximum speed would constitute a hazard for construction workers. 3.3.3 Flashing Arrow Signs These devices can be used to augment conventional traffic control devices where additional warning and directional information is required to control traffic movement through the construction area. 3.3.4 Pavement Markings Pavement markings such as striping, reflective devices, raised pavement markers, and pavement marking arrows can be used to delineate the position of lanes and to designate travel directions. They are especially useful for lane shifting, crossover lanes, and runarounds or other situations in which the usual lanes have been adjusted. 3.3.5 Construction Area Screening Screens that hide construction activity from the view of motorists can prevent gawking and rubbernecking, thus helping to maintain speeds past the construction and reduce the potential for crashes caused by motorist distraction. 3.3.6 Reversible Lanes This strategy is useful when there is strong directional traffic peaking. These lanes require daily lane change set up, however, and thus have limited use. Safety also is a significant issue if the lanes cannot be separated easily by a movable barrier. 3.3.7 Alternate Routes Alternate routes can be used when it is important to close the work area to perform certain construction tasks or when diverting traffic will substantially reduce traffic volumes. These strategies are most appropriate if there is available capacity on routes parallel to the road under construction and the routes can accommodate the mix of vehicles to be diverted. Detour routes might need to be upgraded andor signal timing adjusted to increase capacity or improve traffic flow, making them more attractive to motorists. Coordination with local agencies also is essential. If traffic will be detoured away from the construction, signage will be needed to inform motorists as to where the detour route begins, where it rejoins the road under construction, and where they are to make turns along the detour route. Signage also can be useful on non-turn sections of the detour route to reassure motorists that they are still on the detour and have not missed any turns. 3.3.8 Signal Adjustments Consider changing traffic signal timing if capacity can be increased. Adding or deleting signal phases might be required for changes in travel patterns. Interconnecting traffic signals can help to move traffic through a construction area. 3.3.9 Ramp Metering Traffic flow disruptions can occur at entrance and exit ramps. Ramp metering can be useful where it is necessary to restrict the amount of traffic entering a freeway for capacity or safety reasons. The buildup of queues of vehicles waiting to enter the freeway can have a domino impact for traffic congestion on intersecting roads, however, and must be considered in implementing this strategy. Ramp metering also can divert motorists to alternate routes so adequacy of capacity on nearby roads should be examined. 3.3.10 Temporary Parking and Turn Restrictions One option to increase capacity is to restrict on-street parking, either all day or for peak periods only, to provide for an additional travel lane or to reduce traffic conflicts. It is important to address the concerns of on-street parking for local businesses. Restrictions on turns into driveways and at intersections might be useful or necessary for capacity safety reasons. Restrictions can be during peak periods only or all day. 3.3.11 Moveable Barrier As indicated above in Reversible Lanes the use of moveable barrier may be advantageous, especially if the morning and afternoon peaks have high directional traffic. Moveable barrier should be considered in these situations and provisions for operational costs included. 3.3.12 Truck Restrictions Truck restrictions can increase capacity by both removing some vehicles from the construction area and by increasing the travel speed for the remaining vehicles. It is important with this strategy to identify alternate routes that are suitable for truck traffic. Public information is designed to educate and inform the public about the project, both before it begins and while it is ongoing. It is an essential component of any TM plan and offers several benefits to the project and to motorists. It gives motorists an opportunity to avoid construction sites and frustration and lost time, reduces traffic volumes in the construction area, reduces complaints from drivers who do use the route, and raises public confidence that the Department is well-organized and efficient. Strategies in this group include communication and public outreach tools such as: Fax network Web pages Newsletters and brochures Information letters Community employer meetings News releases media alerts Telephone hotline Paid advertisements and PSAs Posters and billboards Speakers bureau Public information center Highway advisory radio (pre-construction) 3.4.1 Fax Network An effective information strategy in New Jersey is fax network through which information on road, lane, and ramp closures are announced. All eight New Jersey TMAs (Transportation Management Association) provide this service to employers, retail businesses, community groups, libraries, and other organizations who in turn post or distribute the information to employees, customers, and visitors. Some TMAs also provide this information through e-mail to these groups and to individuals who request to be notified. 3.4.2 Web Page The population-at-large is increasingly turning to the internet as a source of information. The Department includes information on a commuter-oriented web page about current and upcoming construction projects, including planned lane closures. Several of New Jerseys TMAs also post construction information on their web pages for projects located in their service areas and provide links to the Department and to other TMAs for information on projects located in other areas. 3.4.3 Newsletters and Brochures Brochures and newsletters are versatile communication tools that can provide information in an attractive, informal format. Both can educate readers about the purpose and benefits of the project, describe the timeline for the work, present tips for avoiding construction, and provide information on TDM services available in the corridor. A map in the brochure or newsletters efficiently conveys the scope of the project, detours, and phases of construction. Newsletters, which are typically larger in size than brochures and frequently have multiple issues, also can carry articles or stories on construction progress. Newsletters and brochures can be useful handouts or mailings for businesses, residents, event planners and community groups but are expensive to produce and become dated quickly. 3.4.4 Information Letters Direct mail is an easy way to communicate with targeted populations, such as businesses, legislators, and local officials, about the project start date. They can be mass-mail form letters or customized to each recipient. 3.4.5 Community Involvement Meetings Public Meetings Employer Meetings Open, public meetings, held both during project development and construction, offer the public an opportunity to learn about the project and ask questions of DOT staff. This strategy can include general meetings or meetings with targeted groups such as businesses, homeowner, and community groups. In the planning and design stages, these meetings can provide DOT with important information for selecting TM strategies. During construction, they can be used to alert the public of construction activities and progress, reducing complaints about traffic disruption. 3.4.6 News Releases Media Alerts The Departments Press Office uses news releases to announce the start and end of all types of projects as well as construction milestones. Primary targets are print and electronic news media and traffic reporters, who can pass the messages on to their audiences, and transportation-related internet web sites. News releases also can be sent to businesses, county and municipal officials, and state and local police. Briefer media alerts can be used to notify newspapers about upcoming temporary construction activities such as lane and ramp closures. Some newspapers will include closure notices in the paper. A round-the-clock toll-free hotline can be established to inform the public about construction schedules, lane or street closures, and transportation alternatives. Tape-recorded messages can be used if they are updated frequently, but personal operators might be appropriate for large projects or to provide return calls for questions that the taped message does not answer. For moderate impact projects, the hotline information service can be included on the Departments existing 1-800-NJROADS hotline. 3.4.8 Paid Advertisements and Public Service Announcements Newspaper and radio advertising and PSAs can be used to convey the main messages of a projects communication plan. They are useful to alert the public that the project will be starting, offer messages about safety in the construction area, and provide information on ridesharing and transit services. For radio ads and PSAs, planning is necessary because ads and PSAs must be scripted, recorded, and distributed. 3.4.9 Posters and Billboards Posters and billboards can be used to announce the start of a major project. Posters may be placed in businesses, public buildings, libraries, community centers, recreational facilities, and other locations that substantial numbers of people visit or pass through. They are most often professionally designed and printed by commercial printers. In view of their high cost, billboards are rarely used, except on heavy volume arterial routes leading to the construction area. They also have limited use because the message must be brief and, over time, motorists have a tendency to ignore them. Planning is very important because billboard leasing must be done in advance and design, printing, and posting are performed by a commercial firm. Smaller, moving billboards also can be placed on the sides of transit buses. 3.4.10 Speakers Bureau This strategy arranges for staff who are knowledgeable about the project to speak to business and community groups, public officials, and the public. Designated speakers can be drawn from Community Relations staff, the Project Manager, the Resident Engineer, Traffic Mitigation Team members, TMAs, and others who are involved with planning and implementation of the TM plan. 3.4.11 Public Information Center A public information center can be established near the construction site. The center can distribute information about the project, display maps of the construction area and mock-ups of the completed project, and provide information about transportation alternatives. As an alternative, Community Relations staff sometimes holds information centers in public spaces during project development. 3.4.12 Highway Advisory Radio (pre-construction) Using low frequency broadcast channels, HAR offers motorists an in-vehicle opportunity to obtain detailed information about future projects in the vicinity and information about alternate routes and other TDM strategies that they could consider using during construction. Information provided to motorists within and in the vicinity of the construction area can alert motorists to delays caused by construction activity and give advance notice of changing operating conditions. The following strategies and tools help to divert traffic to alternate routes during delay periods and improve traffic flow for motorists who remain in the project area: Variable message signs Pre-construction signage Closed Circuit TV (CCTV) Highway Advisory Radio Advance Information Panel Size Variable Message Signs 3.5.1 Variable Message Signs Real-time motorist information provided by VMS play a valuable role in raising awareness and improving safety and traffic flow. VMS can be used for traffic warnings and to alert motorists to upcoming routing changes and lane and ramp closures. They are especially useful where traffic speed drops substantially, significant delays are expected, alignment or surface conditions change, ramps or lanes are closed ahead, or a crash or incident has occurred. VMS used to alert motorists to lane or exit ramp closures might need to be located well in advance of the construction zone or exit if the best alternative route is reached via an earlier exit than the one that is closed or before the start of the construction zone. 3.5.2 Pre-construction Signage Signage can be used prior to the start of construction to inform motorists that construction will be starting. This will help them plan for regular travel through the area during the construction period. These signs, which could be in the form of variable message signs or fixed message signs, can provide a phone number for travel assistance, similar to the POOL number now posted to inform motorists of ridesharing services. 3.5.3 CCTV The need to visually observe and record traffic flow and congestion is critical to the proper management of Variable Message Signs and Highway Advisory Radio. When considering the use of VMS and HAR, the use of CCTV should be considered, as well. 3.5.4 Highway Advisory Radio (HAR) Using low frequency broadcast channels, HAR offers motorists an in-vehicle opportunity to obtain up-to-date, detailed information about current road conditions to supplement information obtained from signage within the construction area. HAR can result in increased diversion of traffic to alternate routes during periods of high volume and during incidents. Fixed or variable message signs alert motorists to the availability and frequency of the radio messages. The adequacy of broadcast quality must be assessed before choosing this strategy. 3.5.5 Advance Information Panel Signs These signs can be used to give motorists information about construction on a different but nearby route. These signs are advantageous where a large number of motorists could be affected by the construction or where it is useful or necessary to inform motorists to avoid a construction area. The objective of travel demand management strategies is to maximize the capacity of the roadway by shifting some motorists from driving alone to multi-occupant modes such as carpools, vanpool, and transit shifting the time at which motorists travel to less congested times and eliminating the need for the trip to be made. Often, TDM strategies implemented by employers and TMA are more effective than those implemented regionally so participation of these partners in the TM plan is highly desirable. TDM strategies include: Rideshare marketing Rideshare incentives and support services Transit incentives and support services Transit service enhancements Park amp Ride lot expansion Employer outreach 3.6.1 Rideshare Marketing The purpose of this strategy, which often is part of a comprehensive public information and outreach campaign, is to encourage motorists who cannot divert to other routes to find others with whom they can carpool or vanpool. It includes such tools as brochures and media advertising promoting ridesharing and informing motorists where they can obtain rideshare matching assistance. 3.6.2 Rideshare Incentives and Support Services Rideshare support services such as ride matching services and Guaranteed Ride Home programs and financial incentives, such as subsidies, discount coupons, or reduced fee carpool parking, can encourage motorists to rideshare rather than drive alone. To be most effective for TM purposes, these strategies must be accompanied by infrastructure strategies, such as Park amp Ride lots, ramp metering that gives preference to carpools and vanpool, and preferential carpool and vanpool parking. The benefits of these strategies can outlive the construction period if some of the motorists who begin ridesharing continue ridesharing after the construction is completed. 3.6.3 Transit Incentives and Support Services Transit support services such as schedule information, Guaranteed Ride Home, on-site sales of transit passes, and financial incentives, such as free or discounted transit and free parking at train stations and Park amp Ride lots can encourage motorists to use transit. As with rideshare strategies, increases in transit ridership that occur during the construction can continue after construction ends. 3.6.4 Transit Service Improvements Increasing the frequency and coverage of transit service in the corridor or on parallel corridors offers motorists new alternatives to driving themselves. If service is operated on the construction route, it can reduce riders frustration over delays. If the service is on a parallel route, it can result in a travel time saving over the time they would have spent traveling along the construction route. Where train service parallels the construction route, shuttle buses from Park and Ride lots to the train stations may be able to divert some traffic from auto to train, improving traffic flow through the construction area. In areas where traffic volume is high, however, it is important to assess whether the rail system has capacity to handle the extra rail riders anticipated and if sufficient rail Park amp Ride lot spaces are available. If rail capacity is available, but Park amp Ride lot capacity is constrained, shuttles from more distant Park amp Ride lots might be appropriate. 3.6.5 Park amp Ride Lot Expansion Improvements to existing lots and the construction of new temporary or permanent lots adjacent to the project corridor can offer convenient meeting places for commuters who are willing and able to rideshare or utilize pick-up points for buses. Because of the cost of construction, this option is most appropriate where Park amp Ride lot capacity is warranted in the absence of the construction and where the new lots are expected to be utilized after construction ends. For temporary lots, spaces might be leased from shopping centers, churches, and other organizations that have primary use of the spaces at times other than during the day. Because numerous tasks, such as identifying, arranging the lease, obtaining insurance, and developing transit links, must be accomplished to institute a temporary lot, planning for this strategy should be started well in advance of the construction start date. 3.6.6 Employer Outreach Employers are important partners in TM efforts because they can have substantial influence over how employees travel to work through incentives they offer and workplace policies they establish. This strategy provides information and assistance to employers to encourage them to implement TDM actions such as telecommuting and flextime that eliminate vehicle trips distributing information about the construction project and TDM options to their employees participating in commute-oriented events and encouraging employees to use alternative modes for commuting. Significant experience with construction projects nationwide has shown that crash rates tend to increase in construction zones because construction activity and unfamiliar and constrained roadway conditions confuse and distract motorists. Some traffic operations and control strategies help to reduce the number of incidents that occur. Incident management strategies are designed to detect and clear incidents quickly. Increased attention to incident management is especially valuable for complex traffic plans with detours and lane closures areas with current high crash rateshigh traffic volumes nighttime construction and projects with a large number of truck movements. Incident management strategies include the following: Incident management plan On-site tow vehicles Enhanced police presence CCTV Traffic monitoring station 3.7.1 Incident Management Plan Event Planning A fundamental TM strategy is a plan for managing and clearing incidents when they occur and for managing traffic around major events occurring in the vicinity of the construction area. An incident management plan typically will define a method to detect incidents quickly establish appropriate diversion routes define the roles assigned to fire, rescue, State and local police, and other emergency response personnel in responding to the incident and define the actions to be taken to clear the incident. Additionally, the plan will identify the location for stores of movable traffic control devices that will be used during an incident and for traffic control during events. Event plans should include the schedule for planned events and traffic control measures to be used. Both incident management plans and event plans must be developed cooperatively with emergency personnel and local officials and agencies within the vicinity of the construction area. 3.7.2 On-Site Tow Vehicles Quick response to incidents is essential to restoring traffic flow one useful strategy is to station tow trucks within the construction area, either all day or during peak periods, to remove disabled vehicles quickly from the area. This strategy should be considered where a crash or breakdown would seriously impair traffic flow and when emergency pull-outs are not available or spaced far apart. 3.7.3 Enhanced Police Presence Police patrols within the construction area can help to ensure that vehicles do not exceed the posted speed limits. On-site, dedicated presence of police also can enhance detection and response to incidents. Additionally, the presence of a parked police vehicle with lights flashing can alert motorists to upcoming construction areas and slow traffic within the area, helping to eliminate crashes and the delays they cause. For large or long-term projects, a traffic monitoring station can provide immediate notification of incidents through closed circuit television and counter loops along the roadway corridor connected though phone lines or communication cables. The detectors also can be useful to measure traffic flow variables as part of an evaluation. It can be difficult to maintain the counters during construction, however, especially if lane shifting is expected. As mentioned earlier, the level of TM applied should be matched to the severity of the travel delay and disruption caused by the project. Too little TM will lead to an unacceptable level of delay and complaints from motorists and businesses. But too much TM will divert resources from other projects. This section explains which groups of strategies are most useful to address various project categories and project characteristics and which individual strategies provide the necessary level of emphasis or aggressiveness for each project category. Table 1 illustrates how project characteristics influence TM strategies. This is intended to suggest which of the six TM strategy areas likely will be needed in the package of TM strategies chosen. Table 2 indicates at which of the four project impact levels various strategies are typically considered, in other words, the level of aggressiveness they are likely to represent. For example, some strategies, such as traffic information fax network, are appropriate for all four levels, while others, such as AB bidding and traffic monitoring station, generally are reserved for high traffic impacts. Table 2 also highlights specific project characteristics, for example, high expected delay or high political sensitivity, that suggest the strategy might be particularly effective needed for a particular project. For example, construction area screening might be particularly needed if the crash rate is expected to increase substantially due to construction activity where lanes must be closed, the roadway has a high ADT, and the project will be of a long duration. Additionally, because the cost of screening is a function of the length of the construction area, the length of the project area might also be a consideration in choosing or not choosing this strategy. Table 1 Potentially Useful Categories of Traffic Mitigation Strategies by Project Characteristic Traffic Mitigation Strategy Categories No alternate route, high traffic volume, long duration, limited project distance, high political sensitivity The preceding sections have described methods and tools the Department can use to assess the need for TM and the level of TM strategies needed. This section describes a more specific discussion of how the Department can integrate these methods and tools into the existing capital project planning process. The Department develops and implements capital projects through a five-phase process: Phase 1 Concept Development Phase 2 Feasibility Assessment Phase 3 Preliminary Design Phase 4 Final Design Phase Phase 5 Construction These phases involve a wide range of planning, analysis, engineering, budgeting, and scheduling activities needed to identify, plan, design, and build roadway improvements. The phases take projects from broad ideas and concepts to final engineering plans that guide construction activities. Each of these phases has a role to play in traffic mitigation. The traffic mitigation activities of each phase are described below, and Exhibit 3 illustrates the basic steps to be accomplished in each of the phases. 4.1.1 Overview of Existing Activities The purpose of Concept Development is to develop and deliver to Feasibility Assessment, a description of well-defined purpose and need and possibly recommend a concept that has been environmentally screened and for which community support has been established. In this first stage of project development, staff will: Identify the transportation problem to be solved, establish its geographic scope, and evaluate the need for the project. Most of this work is preceded with a Tier 2 Screening that may supply this information Identify the Stakeholders Demographics including minority populations and low income populations in the project area Evaluate alternative multi-modal strategies and fulfill CMS requirements Define potential concepts and their limits for short and long-term improvements Identify implementation priorities Define complementary improvement strategies to a highway improvement concept Examine context sensitive designaesthetic opportunities Estimate order of magnitude costs Initiate community involvement with stakeholders, culminating in consensus on the needs and range of solutions In their early exploratory activities, staff perform background research and collect data, such as traffic counts, origindestination distribution, transit availability, travel time data, land use, and other data on characteristics of the roadway, area, environment andor corridor in which the project will be implemented. Next, staff meets with local officials, staff of agencies, and members of the public in the communities affected by the potential project to identify their needs and preferences, and to conduct field research and other studies to define future transportation needs for the area. Third, staff may define one or more conceptual solutions that address the purpose and need, gauge community position, and develop an order of magnitude cost estimate. Staff then compiles all data in the Concept Development report, which is used as the foundation of Feasibility Assessment. 4.1.2 TM Activities in Concept Development At this stage, projects are not well-defined, but some of the project characteristics identified earlier in this paper are known, such as current traffic volumes, crash data, extant substandard roadway features, degree of urbanization, and community impacts. Thus, during Concept Development, it is possible to estimate the impacts likely to be experienced by the public during construction, identify projects that might need or benefit from TM strategies beyond basic traffic control, and propose an initial assessment of the level of TM that might be needed and the general categories of TM strategies that are likely to be effective. Analyze Data on Project Characteristics That Will or Could Influence the Need for TM This step will involve the collection and review of project characteristic data, such as that described in Section 2 of this document. These data will be analyzed to determine the level of traffic and community impacts the project would likely cause. Section 2 offers broad guidelines for defining traffic mitigation levels from project characteristic data. The lead engineer of the Division of Project Planning and Development will fill out the Preliminary Traffic Management Impact Worksheet (Exhibit 2 ) and include it in the Concept Development Report. If a project is determined to be a low impact project, no additional TM activity is required. 4.1.4 Introduce Concepts to Eliminate or Lessen Impacts Community outreach and involvement meetings offer an opportunity to assess the communitys sensitivity to impacts and mitigation options that could gain community acceptance. The Departments Public Involvement Action Plan (PIAP) ensures that communities and other stakeholders are given forums at which projects can be meaningfully discussed. 4.1.5 Identify TM Emphasis Areas At this phase of project development, it is not possible to identify specific TM strategies, but TM emphasis areas will be identified. For example, the areas of emphasis could be secondary use of public information and incident management strategies, with primary use of traffic controls and operations. To the extent that specific strategies within these categories appear to be required or strongly indicated, they should be noted as well. Additionally, project specific needs that are not common to all projects will be noted. These needs will be considered when developing TM strategies related to methods and scheduling of construction. 4.1.6 Document TM Recommendations Finally, the TM recommendations will be documented for use by Scope Development in an Initial TM Assessment. This assessment, which will be prepared for each study, will be included as a chapter in the Concept Development Report and as a TM guide during the Feasibility Assessment. For projects that bypass Feasibility Assessment, the Initial TM Assessment will be provided to the Project Management Group for Preliminary Design. In either case, the Assessment will indicate: Summary of the project characteristics described in Section 2 (Worksheet shown in Exhibit 2 ) with emphasis on the traffic and community impacts of construction Identification of issues for which special TM attention may be warranted Although traffic mitigation needs can be only loosely defined in this phase, examination of TM needs during this early phase is advisable for several reasons. First, introduction of TM into Concept Development permits time for some public input to be solicited as part of the Community Involvement process. Second, some TM strategies require extended lead-time,i.e. addition of NJ Transit bus lines, for development and implementation and should be identified at the earliest possible phase so planning can begin. Third, through community outreach meetings, it will be possible to test early in the process the acceptability of TM solutions to address community impacts. Finally, it is possible that some project concepts would result in unacceptable levels of delay for motorists or other impacts to the community that cannot be cost-effectively mitigated. These impacts then can be included in the analysis and decision-making process conducted through Feasibility Assessment and Preliminary Design. 4.2.1 Overview of Existing Activities During Feasibility Assessment, DPPD performs engineering and environmental analyses and community outreach to determine whether concept alternatives submitted with the Problem Statement can be feasibly evolved into a project. This step is, in essence, a fatal flaw analysis intended to prevent flawed concepts from proceeding to Preliminary Design. It is during this phase that the multi-disciplinary Scope Team is assembled to identify and resolve issues related to the purpose and need developed in Concept Development. The team will discuss alternatives, analyze physical deficiencies, and review the environmental screening. At the end of Feasibility Assessment, DPPD prepares a report that identifies the initially preferred alternative and the rationale for choosing this alternative over the others available, and any outstanding issues in need of resolution. In addition, a Scope Statement for Preliminary Design, which defines the required levels of effort for various design units, is developed. The final steps of this stage are the selection of a recommended alternative and the preparation of the Project Transfer Package that will be submitted to the Division of Project Management. This Package identifies the Recommended Scheme with construction and right-of-way cost estimates documents the public involvement process provides environmental documentation and includes design and cost summaries for any preliminary engineering work performed. 4.2.2 TM Activities in Feasibility Assessment It is during Feasibility Assessment that TM development will begin in earnest. During this stage, traffic mitigation issues will be included in the discussions at Scope Team meetings. In addition, for projects designated as high impact projects, a core Traffic Mitigation Planning Team (TM Team) will be formed as a subset of the Scoping Team. The purpose of the TM Team is to bring together all internal and external entities with a potential role in traffic mitigation activities to ensure that 1) TM planning is consistent across all projects, 2) each involved organization is aware of the TM activities of the others, and 3) TM activities are implemented and coordinated in the most cost-effective manner. At this stage, meetings are conducted to introduce community stakeholders to the alternative recommended to address their problem and to solicit their feedback as to its acceptability. The degree of community involvement varies from one project to another, but all involve some public discussion of both the impacts of the finished project and the costs and impacts experienced during construction. TM Teams also might be established for some moderate impact projects if it appears that multiple strategies will be included. These multiple strategies could necessitate the participation of several outside organizations as well as significant coordination among internal offices. Traffic mitigation for projects with low impacts generally will be addressed sufficiently through Project Scope Meetings held during Feasibility Assessment with minor follow-up of a few internal entities. 4.2.3 Core TM Team Members When the TM Team is first established, it will be comprised of core members, that is, internal and some outside organizations whose involvement is central to the development of the TM plan. Some internal entities will be represented on all TM Teams. During the Preliminary Design phase, the TM Team may be expanded. The core members of the TM Team may include the groups listed below and other interested parties: Division of Project Planning and Development Division of Project Management (Project Manager) Traffic Mitigation Advocate Bureau of Traffic Operations Bureau of Traffic Engineering Bureau of Traffic Signals amp Safety Engineering Bureau of Statewide Planning Office of Communications Community Relations NJ Transit Affected citycounty agencies (e.g. Public Works or Transportation Department) Local Transportation Management Associations TRANSCOM State Police Division of Research and Technology Bureau of ITS Engineering Regional Construction Bureau of Construction Engineering Operations Data Resources Regional Operations Federal Highway Administration The TM Team will have primary responsibility for expanding onadjusting the recommendations included in the Initial TM Assessment prepared during Concept Development. The TM Team will perform three major activities: 1. Define the TM Goals for the Project This step will identify the qualitative and quantitative goals and objectives for the TM program. For example, possible goalsobjectives might be to: Provide work zone speed reductions of 10 mph compared to pre-construction speed limit Reduce traffic volumes by X Decrease average daily traffic by Y vehicles during peak period Maintain LOS D or better Reduce expected delay by Z Keep average delay per vehicle to less than X minutes during the peak period Maintain vehicle-person throughput by increasing auto occupancy and transit ridership Promote public awareness Keep congestion no worse during construction than before Mitigate community impact Maximize safety of workers and the traveling public Keep road user costs below X dollars per day These goalsobjectives serve several purposes. First, they direct TM resources toward the strategies that are most likely to achieve these goals and away from other TM strategies that do not. Second, they focus attention of everyone involved with project development on the expected and desired results. And third, to the extent that the goalsobjectives are quantifiable, they establish targets against which the impacts of possible packages of TM strategies can be assessed during the selection process and provide a measurement standard against which to evaluate the TM effectiveness. 2. Select TM Strategies Next, the project characteristic data will be reviewed to determine, in broad terms, the level of TM (high, moderate, or low) that will be needed to mitigate construction delays and other impacts and to flag concepts for which motoristcommunity impacts during construction might be a fatal flaw. The TM Team will expand on the recommendations provided in the Initial TM Assessment using strategy selection guidance in this document and drawing on their knowledge of the impacts of strategies within their areas of expertise. This initial set of strategies then will be analyzed to determine if it is expected to be sufficient to meet the TM goals established during Feasibility Assessment. This step might require that additional technical analyses, for example, computer simulation of delay or queue length under various conditions of capacity reduction and traffic control, estimates of crash potential, and estimates of trip reduction and route diversion from TDM and public information strategies, be performed. Additional outside research, such as surveyfocus groups, might be considered to estimate the impacts of public information, motorist information, and TDM. If the analysis shows that the initial set of strategies is not sufficient to meet the goals, additional or different strategies should be analyzed, in an iterative process, until one or more TM strategies packages has been identified that will meet the goals. 3. Estimate TM Costs At this point, a preliminary analysis will be undertaken, to estimate the total cost of the package and to compare that cost against the TM benefit to be achieved, with benefit defined as the cumulative road user cost (calculated as defined in the NJDOT Road User Cost Manual ) estimated for the project. Although road user cost does not capture all impacts to all groups, it can serve as a useful starting point when determining an acceptable cost for the TM package. Costs to other stakeholders, such as retail businesses and employers, might also be estimated and considered when determining a total cost for the TM program. The Department might decide that motoristsbusinesses should bear a portion of the cost of the improvement by accepting some degree of delay and disruption. If so, the acceptable TM cost will be proportionately below the road user cost. Road user costs at least should be considered the upper limit on TM program costs. If improvements are required to other facilities, such as road widening or intersection improvements for detours, these may be justified based on road user benefits. If the TM package cost is considered too high relative to the benefits obtained, some TM strategies can be eliminated from the package or replaced with less costly strategies. 4.3.1 Overview of Existing Activities Several significant TM components will occur during Preliminary Design, including refinements to the strategies and development of the Draft TM plan. During the design phase, TM implementation also can begin. It will become the responsibility of the Designer to incorporate into design plans the recommendations for strategies, such as detour routes and temporary roadway improvements that require construction activities. At this same time, the TM Team can begin to plan for implementation of strategies, such as public information and TDM, that are implemented outside the conventional design process. 4.3.2 TM Activities in Preliminary Design 4.3.3 Expand Core TM Team Up to this point, TM planning has been primarily the responsibility of internal staff, with a few outside parties involved as needed. For moderate impact projects, this core TM Team probably will be adequate, but the TM Team almost certainly should be expanded during Final Design at least six to nine months before the start of construction for high impact projects, especially if the project has very high community impacts. The role of these additional members will be to help finalize the TM plan and participate in strategy implementation. Supporting members of the TM Team might include the following: Office of Communications Other transit operators Elected officials of affected citycounty Transportation authorities (e.g. Parkway, Turnpike) Local Police Emergency services Business representatives Activity centers (e.g. arenas, shopping centers) that will experience major impacts Consultants working on TM implementation activities Additionally, for high impact projects, subgroups of the TM Team may be established to focus on specific topics such as traffic operations, public information, and TDM. These subgroups can meet separately from the rest of the TM Team to address issues that relate only to their responsibilities. 4.3.4 Initiate Implementation Planning As noted earlier, some strategies will require long planning, construction, or implementation lead-time. Planning for these strategies should be started during Preliminary Design to ensure they are in place when construction on the main project begins. If local agencies or other groups are to be involved in implementing these strategies, any cost-sharing agreements should be implemented quickly so that the agencies and other groups are given adequate time to complete their responsibilities. 4.3.5 Prepare Draft TM Plan The next TM step will be to develop a draft Traffic Mitigation Plan (TM plan), which will accompany other project documentation into Final Design Development. This TM plan, which will be developed by the core TM Team, will be more detailed than the Initial TM Assessment prepared under Concept Development. It will include the following components: Recap of project characteristics (from Initial TM Assessment) with emphasis on the traffic and community impacts of construction Results of analyses conducted to select TM strategies Detailed description of individual TM strategies selected and their applicationinstallation Approximate TM implementation schedule with critical components noted Responsibilities of the Department, contractor, and other outside parties Detailed estimate of TM costs, sources of funding (if outside contributions will be obtained), and cost-benefit assessment Proposed monitoring and evaluation activities 4.3.6 Estimate TM Costs At this point, a second analysis step will be undertaken, in the same manner as was done during Feasibility Assessment, to refine the cost of the package and to compare that cost against the TM benefit to be achieved. With a more detailed cost analysis, the cost benefit comparison should be re-evaluated if the TM package cost is considered too high relative to the benefits obtained, some TM strategies may be eliminated from the package and replaced with less costly strategies. 4.3.7 Define TM Schedule In this step, a schedule will be developed for implementing TM strategies. The schedule should indicate when strategies will be installed, initiated, or placed into service but also should identify strategies that have long lead-time requirements. These strategies might include improvements to other road facilities strategies for which equipment must be ordered and installed and strategies, such as planning of bus service and construction of Park amp Ride lots, for which implementation requires the assistance of outside partners. 4.4.1 Overview of Existing Activities During Final Design the construction plans are finalized and community relations activities, project budgeting, scheduling, and contractor selection tasks are completed to prepare for the start of construction. 4.4.2 TM Activities in Final Design Development By the time Final Design begins, TM planning is nearly complete. The strategies, costs, and implementation plan should have been developed. During Final Design, the details of the TM plan are refined and solidified to prepare for construction. The major activities that occur for TM during Final Design Development are the following: 4.4.3 Incorporate TM plans during Quality Assurance (QA) Team Review In this step, planned TM strategies also will be included in discussions during Constructability Reviews to ensure that the selected TM strategies are consistent with project phases and efficient construction operation and management, and that no significant constructability issues have been overlooked. 4.4.4 Adjust TM Plan for Design Changes It is expected that the final design plans will closely follow the Project SOW, on which the TM plan is based. It is not uncommon, however, for the SOW to be modified due to some factor that could not be predicted during Scope Development or even during Preliminary Design. These design changes might affect the types or level of effort on one or more of the TM strategies included in the Draft TM plan. The TM planning Team will be consulted if design choices suggest a modification is appropriate or needed. In most cases, these changes will be minor and will be easily incorporated, with small adjustments, into the draft TM plan. But in cases where the design changes are extreme or substantial, it might be necessary to return to the TM strategy selection and analysis process first conducted during Scoping. 4.4.5 Prepare Final TM Plan The next TM step in Final Design is to finalize the TM plan. The Final TM plan, which will be developed by the core members of the TM Team and reviewed by the expanded group, will include similar components to those included in the Draft TM plan. However, a higher level of definition with a focus on what, how, when, and by whom TM activities are to be accomplished is expected. The TM plan will include: Recap of project characteristics Results of analyses conducted to select TM strategies Detailed description of individual TM strategies selected and their applicationinstallation TM implementation schedule with critical components noted Responsibilities of the Department, contractor, and other outside parties Detailed estimate of TM costs and sources of funding (if outside contributions will be obtained) Monitoring and evaluation activities 4.4.6 Review TM Plans during QA Team Review Again, the QA Team will review the planned TM strategies during Constructability Reviews. 4.4.7 Collect Evaluation Baseline Data This TM activity occurs as Final Design is being completed and the start of construction nears. In this step, various members of the TM Team will collect data on current conditions, relevant to the TM strategies in their area, to allow a comparison against the same conditions during the construction process. 4.5.1 Overview of Existing Activities During the Construction phase all components of a Transportation Management Plan should be completed or implemented. 4.5.2 TM Activities during Construction 4.5.3 Preconstruction Conference The final step in the TM plan development process occurs after the construction contractor has been selected, i.e. when the contractor meets with Departmental staff during the preconstruction meeting. Discussion of each phase of work and the provisions to maintain traffic during each phase. The Department should require the contractor to designate a Traffic Control Coordinator responsible, on a 24-hour basis, for TM activities. 4.5.4 Value Engineering Changes to the TM plan proposed by the contractor can be submitted as Value Engineering proposals. The Department is under no obligation to accept the proposed change. Review and consideration of such a proposal will follow the specified VE process. A special attention to commitments made to external stakeholders shall be made in the evaluation of a VE proposal or a change that will affect a TM plan. The VE proposal may need to include public outreach efforts in order to ensure that external stakeholders interests are upheld. The preceding parts of this section described TM activities that occur before construction begins. The majority of these activities cover planning, although some modest implementation, such as construction of Park amp Ride lots, also can occur during these pre-construction stages. During construction, the emphasis shifts to implementation of TM strategies, following the TM plan finalized in Final Design, and the evaluation of the effectiveness of the strategies in meeting TM goals. As construction proceeds, it is possible that some adjustment of TM strategies might be needed. For example, a mid-project evaluation could show that the implemented strategies were not having the desired results or were unnecessary or underutilized. This might suggest that new strategies or modified versions of the existing strategies should be implemented during construction. For this reason, TM Team members responsible for strategy implementation and evaluation will monitor strategy performance and review results of interim evaluations and recommend strategy adjustments to the TM Team and the Project Manager. Further, it is possible that the project itself could change during construction, for example, to incorporate VE proposals submitted by the contractor or due to other factors unrelated to the performance of the existing TM strategies. In such cases, the TM Team will assess the impact of the changes on the appropriateness and likely effectiveness of the TM strategies implemented previously and will make recommendations to the Project Manager. These recommendations could include modifications to the TM strategies. Alternatively, if the project changes would require TM strategies that conflict with agreements made with external stakeholders, the TM Team could instead recommend that the proposed project changes not be implemented. The traffic management strategies to be applied during a project must be documented along the development process to establish a point of reference for subsequent steps and, ultimately, to guide implementation of the strategies. The Traffic Mitigation Guidelines, which has focused attention primarily on those projects for which significant TM activities will be necessary, has mentioned several required TM documents. These documents are summarized here, along with guidance regarding when they are needed and the components to be included. Three primary documents will be prepared for TM activities: Initial TM Assessment, Draft TM plan, and Final TM plan. These documents will be prepared during Concept Development, Initial Design Development, and Final Design, respectively. Each will be progressively more detailed than the previous document as the details of the project become more certain and the TM strategies more defined. It is important to note that the level of TM documentation needed for a project will vary, depending on the level of TM to be applied. It is important that TM concepts be considered for all projects however, many projects will have little or no TM impact - - it is not the Departments intent to expend resources on documentation when it is not needed. The following is a discussion of the use and components of the three documents, along with an indication of the projects for which these reports will be prepared. 5.1.1 Initial TM Assessment TM recommendations defined during Concept Development will be documented in the Initial TM Assessment. This assessment report will be included as a chapter in the Concept Development Report, part of the package to be provided to Scope Development. The purpose of the Assessment is to identify the likely need for TM and the project issues that affect the need for TM. The Assessment will include the following sections: Summary of the project characteristics described in Section 2 of this document (TM Impact Worksheet shown in Exhibit 1) with emphasis on the traffic and community impacts of construction Identification of issues for which special TM attention may be warranted A TM Assessment will be prepared for each project concept, but the level of detail and the length of the report will vary with the level of project impact. The Assessment prepared for a low impact project is likely to be very short with little more than a brief explanatory attachment to the Preliminary Project TM Impact Worksheet shown in Exhibit 1. Assessments for projects with more significant levels of TM impact will be more substantive as they need to provide more detailed guidance for TM consideration in Scope Development. 5.1.2 Prepare Draft TM plan The second TM document to be prepared is the Draft TM plan, which will be prepared during Preliminary Design. This Draft TM plan will be developed by the TM Team, with various members of the team preparing individual sections of the plan that relate to their areas of expertise. The Project Management Group will be responsible for coordinating TM plan development. The TM plan will be more detailed than the Initial TM Assessment and will include the following components: Introduction Brief description of the project (location, project needobjectives, and proposed improvements) Project Characteristic - Recap of project characteristics (from Initial TM Assessment) with emphasis on the traffic and community impacts of construction Analysis Results - Results of analyses conducted to select TM strategies, including delay simulations, estimate of road user costs, analyses of strategy effectiveness, public surveys, crash rate simulations, and any other analyses TM Strategies - Detailed description of individual TM strategies selected and discussion of how they will be appliedinstalled. TM strategies are to be grouped into three categories: Public Information, TDM, and Operations (including strategies for construction and contracting, traffic control and operations, motorist information, and incident management). Implementation Schedule - Approximate TM implementation schedule with planning and implementation milestones noted for critical components Planning and Implementation Responsibilities - Responsibilities to be performed by the Department, contractor, and other outside parties TM Costs - Detailed estimate of TM costs, sources of funding (if outside contributions will be obtained), and cost-benefit assessment Evaluation Outline of proposed monitoring and evaluation activities A Draft TM plan will be established for all high impact projects. A TM plan will be developed for moderate impact projects that include some or several of the following characteristics: High traffic volume for the type of roadway Significant detrimental impacts on mobility for local or through traffic Significant reduction in capacity through lane, ramp, or intersection closures Alternate routing will be necessary Timing will negatively affect activity centers or other events held within the corridor Significant impact on local communities and businesses 5.1.3 Prepare Final TM plan The third TM document is the Final TM plan. This TM plan also will be developed by the core members of the TM Team and will be reviewed by members of the expanded TM Team, if additional members have been added beyond the core membership. The Final TM plan will be organized in the same manner as the Draft TM plan and include similar components to the Draft TM plan. The Final TM plan will reflect any design changes made during Design Development and a higher level of definition of each plan component, with a particular focus on implementation: how, when, and by whom TM plan activities will be accomplished. The specific components of the Final TM plan will include: Introduction Brief description of the project (location, project needobjectives, and proposed improvements) Project Characteristic Recap of project characteristics with emphasis on the traffic and community impacts of construction Analysis Results Results of analyses conducted to select TM strategies, including delay simulations, estimate of road user costs, analyses of strategy effectiveness, public surveys, crash rate simulations, and any other analyses TM Strategies Detailed description of individual TM strategies selected and discussion of how they will be appliedinstalled Implementation Schedule Approximate TM implementation schedule with planning and implementation milestones noted for critical components Planning and Implementation Responsibilities Responsibilities to be performed by the Department, contractor, and other outside parties TM Costs Detailed estimate of TM costs and sources of funding (if outside cont ributions will be obtained) Evaluation Definition of the evaluation measures to be used to evaluate TM effectiveness and a detailed description of the monitoring and evaluation activities to be performed, including baseline data collection, surveys to be conducted, traffic counts, delay measurement, crashincident tracking, and any other evaluation activity. The Final TM plan will be provided to all members of the TM Team, other Departmental entities with an interest need to be informed of the planned TM activities, outside parties that will participate in implementation, and the contractor performing the construction. If any design changes are made during construction that affect any part of the TM plan, Construction shall inform the Traffic Mitigation Advocates Office. 5.1.4 References to Traffic Mitigation in Other Project Planning Documents The purpose of this document is to present a broad framework for incorporating TM planning and implementation into the existing capital projects planning process. It is expected that individual NJDOT units will develop additional instructions to guide their staff in the proper application of TM procedures and responsibilities established for their units. Additionally, the procedures described in this document are to be referenced in the CPM Procedures Manual and addressed in tools used in the project development process, including Quality Assurance Checklists for Initial and Final Design Project Scoping Checklists Quality AssuranceConstructability Reviews Constructability Checklists and the Construction Progress Schedule. Once construction has begun, it is important to monitor the progress and use of individual strategies, track the costs of the strategies, and evaluate their effectiveness in mitigating impacts caused by the construction. Monitoring will allow fine-tuning of strategies - - adjusting or augmenting them if they are not producing the necessary and desired results. For example, ridership counts on temporary transit vehicles might show that buses are underutilized suggesting additional marketing might be needed. Alternatively, the counts might show that the buses are very crowded suggesting additional bus runs should be operated. Similarly, monitoring of delay time on alternate routes might indicate that revised signal timing or additional police enforcement will be needed to use these routes most effectively. Evaluation of the successes and problems encountered also will provide feedback to guide the development of traffic mitigation activities for future projects and help avoid future problems. Although no two projects are completely alike, many similarities will exist across projects. Results of the traffic mitigation findings of one project will be useful input to the development of TM plans and the allocation of TM resources for other projects. TM plan evaluations will focus on the performance of both individual TM strategies and overall performance of the construction corridor or facility. Evaluation should be based on measures of effectiveness that are tied to the TM goals set for the project and use methodologies and measuring tools generally recognized and accepted in the discipline covered by the evaluation. Various evaluation measures are appropriate for assessing corridor and strategy performance. This section suggests key measures and associated measuring methods. Various Departmental units will have a role in collecting and interpreting evaluation data. The Traffic Mitigation Policy document identifies these units and the TM strategies they will be responsible for evaluating. Baseline data will be collected prior to the start of construction, and most evaluation data will be collected during the construction phase of the project however, for some evaluation activities, post-construction evaluation also might be appropriate, as noted below. 6.1.1 Evaluation Measures Corridor performance is the bottom line of evaluation. Key evaluation measures for both construction facilities and alternate routes include: Traffic volumes (within the corridor and on parallel routes) Traffic flow (LOS, delay time, length of delay period) Vehicle occupancies Bicycle and pedestrian traffic in corridor Crash rates and severities and incident frequency Project durationacceleration These measures should be assessed regularly during construction and be assessed for both peak and off-peak times. Measurements should be made before, during, and after construction to examine short- and long-term impacts. For TM plans for high impact projects, evaluation also should track at least some of these measures on non-affected corridors of similar type of roadway for control purposes in order to rule out the effects of exogenous factors, such as gasoline prices, on the observed results. 6.1.2 Data Collection Methods Various methods can be used to evaluate corridor performance. Standard machine counting or video procedures can be used to make traffic counts. Several methods can be used to estimate vehicle occupancy. Direct observation is the most direct and accurate method to measure occupancy in slow-moving traffic. Another method is to include occupancy questions in a standard origin and destination survey which is mailed to users of the construction facility who have been identified through license plate monitoring. It can be difficult, however, to obtain a sample that is representative of the total traffic population. Past experience with response rates and confidence levels should determine the necessary sample size for statistical confidence. 6.2.2 Evaluation Measures Some construction strategies can be evaluated by comparison with conditions prior to implementing the strategy and with conditions on similar facilities without the strategies in place. For example, lane and ramp closures and two-way traffic on divided highways can be evaluated based on traffic, delay, and accident conditions prior to and after implementation, taking care to control for beforeafter factors through a non-construction, control facility of similar type and traffic. Controls are important as traffic volumes and accident rates can change for other reasons, especially if the project extends over several years. Contract management strategies such as A B bidding can be evaluated by comparing project or phase duration to the anticipated projected schedule and the time it took to complete similar projects or phases in other areas. Lane rental can be evaluated similarly, by comparing the number of hours lanes were projected to be closed to the actual number. When evaluating incentives and disincentives, it is important to estimate all possible benefits and costs. For example, the potential of finishing the project early must be tempered by other factors, such as delay and crash risk. If large delays results from a fast track approach, these negative effects must be considered in the evaluation as well. 6.2.3 Data Collection Methodologies The mechanisms for evaluating travel impacts of lane and ramp closures and two-way traffic on divided highways are similar to those for tracking general corridor performance, as noted earlier in this Section. Standard machine counting or video procedures can be used to make traffic counts. Vehicle occupancies can be measured by direct observation or video, and through surveys, as noted before. VMT can be assessed through survey questions asking about trip length. The same cautions about sample size also apply here. Delay and speeds can be measured through floating or test car procedures. 6.2.4 Traffic Control and Operations 6.2.5 Evaluation Measures As with construction strategies, many traffic control strategies can be evaluated by comparison with conditions prior to implementing the strategy and with conditions on similar facilities without the strategies in place. Reversible lanes, ramp metering, and truck restrictions, for example, can be evaluated based on volume of traffic, delay, and accident conditions prior to and after implementation. Other strategies, such as temporary reduced speed, barriers and channelizing devices, and construction area screening also can be measured through assessment of delay speed also can be used to assess the effectiveness of these strategies. Strategies that affect routes off the corridor, such as ramp metering, alternate routes, and temporary parking restrictions, potentially affect not only the construction route but also parallel routes, in essence relocating traffic congestion. Therefore, similar evaluation measures of delay, volume, and speed on these routes also should be measured. Typical measures evaluated for these strategies include: Traffic volumes and peak traffic counts (construction and parallel routes) Vehicle throughput Vehicle occupancy counts Bicycle and pedestrian traffic in construction area Travel delay and travel time Crash rates 6.2.6 Data Collection Methodologies Data collection tools for traffic control and operations are similar to those used to measure the overall corridor performance. These include standard machine counting or video procedures for traffic counts direct observation and occupancy questions on surveys to assess vehicle occupancy and timed runs in a floating or test car to assess travel time or average travel speed. For channelizing devices, reduced speed limits, and flashing arrow signs, direct observation of motorist behavior might be most useful to determine the degree to which travel change is occurring. Video recording also could be useful to determine to what degree traffic is slowing or diverting as requested. Observation over longer periods of time can be used to reveal patterns of change, such as times of heavy traffic vs. light traffic conditions or daytime vs. nighttime behavior. 6.2.8 Evaluation Measures Public information serves two purposes in traffic mitigation. First, it informs the public about the purpose of the project and generates and maintains public support for the project. Second, it encourages changes in travel behavior during the project to minimize delay and accidents. The principal objectives of public information monitoring are to determine 1) is the public getting accurate information and 2) is the information changing travel behavior Evaluation measures that can be used to determine the availability and accuracy of information generally focus on identifying the sources used by the public to obtain information and the perceptions they form toward various aspects of the project. For example, typical evaluation measures might include: Percentage of public-at-large and motorists in corridor who are aware of the project Motorists perception of the reason the road is under construction Percentage of public-at-large and motorists in corridor who are aware of alternate routes and alternate modes of travel Sources (brochures, traffic reports, news articles, etc.) used by motorists to learn about the project Public perceptions regarding clarity, availability, and usefulness of information Number of requests for information (web site hits, customer service phone calls, etc.) For the second objective, change in travel behavior can be measured by Percentage of motorists in the corridor who change their time of travel or their route Number of travelers who rideshare in the corridor Number of travelers who bicycle or walk in the corridor Transit load factorsridership in the corridor compared to a pre-construction baseline 6.2.9 Data Collection Methodologies Determining how well information is distributed and understood can be established by tracking the number of information requests and the level of media attention, and by conducting surveys and focus groups with members of the public-at-large and with the motorists who use the corridor. Telephone survey and mail-out surveys can be directed toward travelers identified through license plate monitoring. Another method is the repeat panel, in which a group of travelers is periodically surveyed on their awareness throughout the project. Surveys can be used to determine any changes in motorist behavior as a result of the information. Travelers who respond to awareness surveys can be grouped by their level of awareness to determine if those with higher awareness levels were more likely to change their travel patterns. Another method is to ask those making travel changes why they have done so, what sources of information they received, and what information relative to other factors influenced their decision. Questions about both awareness and behavioral change must be structured carefully. Questions should begin by tapping unprompted recollection of messages and information about the project. When recollection has been established, additional questions can be used to probe specifically about the sources of information, perceptions formed as a result of the information, and the helpfulness of the information. 6.2.10 Motorist Information 6.2.11 Evaluation Measures Motorist information strategies, including signing and highway advisory radio, can be evaluated on the same basis, and by using some of the same evaluation measures, as for public information. Here, however, the first evaluation objective is whether or not motorists are aware of the information transmitted and whether the information is useful to specific on-road decisions they are making while they are in the construction corridor. 6.2.12 Data Collection Methodologies Two appropriate evaluation methods include a survey of motorists in the corridor and direct observation of motorist behavior. As with evaluation of public information strategies, mail or telephone surveys can be targeted to travelers using the corridor. Questions can be asked about whether the motorist tuned in to the highway advisory radio or if they noticed the variable message signs. Questions also can be asked about how travelers responded to the information received. Follow up questions might be asked of motorists who said they did not hear advisory radio or read the sign. For example, they could be asked if they did not know about the radio or did not believe the information would be useful. Motorists who use the HAR could be asked about the message content, accuracy (considering current conditions), and length. For variable message signs, evaluation might focus on patterns of sign recognition to determine effectiveness. Perhaps signs highlighted with arrow boards get higher recognition than those that do not. Evaluation also could ask about motorists lane location to determine if they were able to see and read the signs clearly from various lanes. Another method to evaluate effects of motorist information is through observation. Presuming the requested behavior change is relatively soon after the message, observers can determine the degree to which travel change is occurring. Video recording also could be useful to determine to what degree traffic is slowing or diverting as requested. Observation over longer periods of time and some weeks after message signs have been installed can be used to reveal patterns of change, such as daytime vs. nighttime behavior or times of heavy traffic vs. light traffic conditions. 6.2.13 Demand Management 6.2.14 Evaluation Measures The effectiveness of TDM strategies can be measured indirectly through improvements to traffic flow but, in general, they are measured through usage and the number of vehicles they remove from the construction corridor. To determine vehicle reduction, it is necessary to identify the previous mode used for travelers who are using rideshare modes and transit. It is important, however, not to assume that every non-SOV traveler is new to that mode. Some alternate mode users will have been using an alternative before construction began. For example, the implementation of temporary bus service can attract some travelers who were previously carpooling. Other measures of TDM success are the share of travelers using alternative modes and the average occupancy of vehicles using the corridor. Typical evaluation measures for TDM strategies include: Train and bus ridership Number of new carpools and vanpools Alternative mode share, vehicle occupancy Park amp Ride lot usage Number of requests for rideshare information 6.2.15 Data Collection Methodologies Various methods can be used to determine the effect of TDM strategies on corridor performance. One way to measure the effectiveness of general ridesharing campaigns is to survey a sample of rideshare applicants following a promotion in order to determine if the campaign, or a specific incentive provided in the corridor, influenced the applicant to submit an application or to change modes. Specific new services, such as transit enhancements and Park amp Ride lots, can be measured through ridership or usage counts. Additionally, on-board or intercept surveys can be used to identify prior mode, trip length, and other variables related to vehicle trip reduction and VMT reduction. Employer-based TDM actions also might be assessed to determine the contribution of telecommuting and other employer actions to vehicle trip reduction. The usual tool for assessing employer program effectiveness is an employee survey in which current travel patterns and previous travel patterns are compared. The result of the survey is an assessment of the reasons for any changes in patterns. 6.2.16 Incident Management 6.2 17 Evaluation Measures The key strategies included in incident management are designed to detect and respond to accidents. Thus, incident management should be evaluated on the basis of how well it reduces response and removal time for accidents and incidents. Incident frequency also might be measured if it is measured over a long period of time or measured against comparable incident rates for equivalent-type, non-construction corridors. Evaluation measures for these strategies could include: Number of accidentsincidents Ratio of incidents per traffic volume within construction zone to other freeways Incident responseclearance time Delay time during incidents 6.2.18 Data Collection Methodologies Incident detection is more difficult to measure than response time because the actual moment the incident starts can be difficult to assess. Detection can be measured most easily where video surveillance records an accident or shoulder stop. By providing a real time basis for the incident and by reviewing logs of the State Police and other emergency services, it is possible to determine how long after the actual incident the detection occurred. Response and removal time can be assessed by comparing the log time of the incident detection with the arrival on the scene, as recorded by the police or responding emergency service, and the time at which the roadway is cleared of the incident, again as recorded on police logs. The State-Level Processes and Procedures provide a systematic approach for addressing and managing the safety and mobility impacts of work zones. The safe and efficient flow of vehicles, pedestrians, and bicyclists through construction work zone areas is a major Department concern. Its importance has recently been echoed by the Federal Highway Administration as is evidenced in the September 9, 2004 rulemaking on Work Zone Safety and Mobility. All states are to be in compliance with this Rule by October 12, 2007. This document addresses the program level procedures, and works in conjunction with the Work Zone Safety and Mobility Policy, the Work Zone Safety and Mobility Project-Level Procedures, the Traffic Mitigation Guidelines, and other Department procedures. 7.3.1 Traffic Mitigation Advocate The TM Advocate manages TM Policies and Procedures to ensure that the Departments traffic mitigation goals of safety and mobility are realized. The position of Traffic Mitigation Advocate has been established under the Assistant Commissioner of Capital Program Management. The Traffic Mitigation Advocate is responsible for overseeing: Work Zone Policy amp Procedure Development amp Implementation Work Zone Assessment and Management Work Zone Data Evaluation Work Zone Safety and Mobility Training Programs Work Zone Safety and Mobility Process Review Additionally, the Traffic Mitigation Advocate will strive for continuity of TM strategies from Concept Development through Construction, as projects are transferred from one phase to the next. The TM Advocate should have the following qualifications and skills: Understanding of a great range of TM techniques Knowledge of project delivery schedules and alternate project delivery methods Understanding of activities of major NJDOT units with a role in traffic mitigation and the project delivery process Sensitivity to the needs of the traveling public and impacted communities, and an ability to build acceptable balanced solutions Understanding of project management tools and techniques used by Capital Program Management, such as road user costs, cost estimating, value analysis, and design decision tools The TM Advocate will also play a supportive role in traffic mitigation areas led by the Subject Matter Experts and will: Review Department procedures manuals, design guides, standard specifications, and other applicable documents and incorporate the details of the adopted TM Policy and Procedures into these documents where applicable Modify Traffic Mitigation Policy and Procedure s as needed to adapt to any modifications to the current project delivery process and update to reflect current industry practices or innovative strategies Address, as necessary, Traffic Mitigation related procedures for Operations and Maintenance, Local Aid, and permit construction projects 7.3.2 Work Zone Assessment and Management The TM Advocate will assist the lead unit responsible for a specific project delivery phase by: Serving as a subject matter expert and advisory on traffic mitigation topics and as an advocate for developing and implementing programmatic traffic mitigation strategies throughout the project delivery process. The Advocate will serve to resolve conflicts between units during concept development, project scoping, design, and construction. Assisting Project Manager to facilitate and coordinate TM activities conducted by other units and assist with the preparation of draft and final TM plans. Maintaining on-going dialogue with other transportation agencies to ensure that traffic mitigation strategies are considered for all transportation facilities impacted by all transportation projects and that project schedules are coordinated among agencies to avoid unnecessary conflicts. Assisting Local Aid, and Maintenance and Operations to make recommendations for traffic mitigation strategy. 7.3.3 Work Zone Data Evaluation Field observations will include utilizing the latest available traffic information to help determine the impacts to traffic. If shoulders or lane closures are proposed that will generate queues, road user cost calculations may be performed to determine the operational impacts in terms of average travel delays. Work Zone Set-ups shall follow Department standards. In addition, only NCHRP 350 approved safety items will be considered acceptable. Historical work zone crash data shall be maintained and evaluated for possible work zone safety improvements. 7.3.4 Work Zone Safety and Mobility Training Construction and work zone personnel shall be trained in work zone safety as per Department guidelines as it relates to implementation, operation, inspection, and enforcement. Designers shall be provided with guidelines and standards to properly develop safe and efficient work zones. Periodic training updates that reflect changing industry practices and Department processes and procedures shall also be provided. The Project-Level Procedures provide guidance and identify key steps to be addressed on individual projects from Planning through Construction to ensure work zone impacts are managed in accordance with the Work Zone Safety and Mobility Policy. Work zone safety and mobility impacts will vary depending on the work zone, location, duration, and roadway capacities and volumes. The responsible parties involved vary with the subject matter and the project phase: Traffic Mitigation Advocate Exhibit 4 outlines key steps involved in the development of a Transportation Management Plan to address work zone safety and mobility concerns. Exhibit 4 Work Zone Safety and Mobility Key Steps The Transportation Management Plan should be developed with input from stakeholders and interested parties. The extent of this outreach will generally increase as the anticipated impacts increase. Stakeholders may include public officials, police, fire, schools, emergency medical services, other transportation agencies, transit providers, utilities, business communities, and other interested parties. Traffic mitigation efforts are required during each major project development phase. The units involved will change as the project evolves from Planning through Construction. The key units involved in planning, project development, design, and construction shall consistently and comprehensively apply traffic mitigation strategies to provide safe, efficient, cost effective work zones for both construction and the traveler. Any questions or comments in regards to policies or procedures should be directed to the Traffic Mitigation Advocate. Each unit has their own procedures that are continually being refined. Many topics discussed here have procedures that are contained elsewhere by other units. The procedures shall be supported and supplemented by, but not limited to, the following documents: Work Zone Safety and Mobility Policy NJDOT Work Zone Safety and Mobility State-Level Procedures NJDOT Road User Cost Manual NJDOT Traffic Mitigation Guidelines FHWA Work Zone Rule -23 CFR Part 630, September 9, 2004 NJDOT Work Zone Set-Up Guide NJDOT Capital Project Procedures. Design Manual. Specifications. Construction Details, and Sample Plans Road user costs tend to become significant when the traffic volumes exceed capacity. Road user costs exist due to any delays, whether work zone related or not. As an example, Exhibit 5 shows the cost of a one minute delay for 10,000 vehicles. Traffic mitigation strategies should be considered when the benefits of reduced road user costs exceed the increased construction and related mitigation costs. In work zones, the NJDOTs Road User Cost Manual values are the differential road user costs of added vehicle costs and delay costs created by the queues and reduced speeds caused by the work zone. Clearly, road user costs can be significant. When comparing design and construction costs to road user costs, the road user costs should typically be weighted within the range of 10-25 of the calculated road user cost value. บันทึก . Values based on 2006 cost rates. To calculate costs for 20,000 vehicles per day, multiply costs by two. To calculate costs or two minute delay, multiply costs by two. Capital Program Management procedures are outlined below. The Operations and Local Aid groups have their own procedures that follow the Work Zone Safety and Mobility Policy and State-Level Procedures guidelines. 8.3.1 Concept Development (Feasibility Assessment if Pipeline 1 or 2 project) The analysis of traffic volumes and capacities is foundational for the development of traffic mitigation strategies. The Division of Project Planning and Development (DPPD) shall acquire 24 hour weekday and weekend truckcar counts for the project area. These should include mainline and detour route volumes and, if applicable, side street volumes at signalized intersections. Turning movements at key intersections and interchanges shall be provided for peak hour periods. This data shall either be created by, or forwarded to, the Bureau of Transportation Data Development (TDD) which maintains a centralized data base of all traffic volume counts. 8.3.2 Feasibility Assessment The evaluation of traffic volumes through various work zone capacities and detour routes will help the Designer understand traffic impacts associated with various lane closure alternatives. The Designer will evaluate the alternatives on a 24 hour basis to determine when there would be queues. Exhibit 6 shows a sample Capacity versus Traffic Demand chart. The Departments Subject Matter Expert is the Road User Solutions Unit from the Bureau of Smart Solutions amp Value Management. Exhibit 6 Capacity versus Traffic Demand Illustration For evaluation of detours, the average detour length and delay times shall be determined by the designer. The NJDOT Road User Cost Manual provides greater detail in these matters. The number of lanes available in a work zone plays a significant role in the work zone capacity. Work zone capacity charts are in the NJDOT Road User Cost Manual. Basic Work Zone Staging Scenarios in the manual provide the designer with the ability to quickly evaluate minimum width requirements for various lane closure scenarios. The Department recognizes the public does not like to experience traffic delays due to construction. Therefore, in its evaluation matrix, the Department should include an alternative that introduces no traffic queues (i.e. volumes are less than capacity). Common methods to avoid queues are modifying the allowable lane closure hours and utilizing shoulder areas as temporary lanes. If this no congestion scenario can be cost effectively accommodated and becomes the initially preferred alternative, the work zone will have Low Impacts. 8.3.3 Preliminary Design For projects that will have anticipated queues, the Designer shall utilize the NJDOT Road User Cost Manual to provide a preliminary analysis of the actual road user costs. There are a multitude of traffic mitigation strategies that are available. Depending on the project location and severity of the anticipated impacts, different strategies will be appropriate and the most cost effective. Mitigation strategies may be temporary in nature or provide permanent improvements. Typical strategies include limited lane closure hours, shoulders as lanes, liquidated damages for lane occupancy and road user charges, intelligent transportation services (ITS) including real time traffic information, movable barrier, temporary roads and bridges, temporary traffic signals, detours, accelerated construction, pre-cast items, and A B or IncentiveDisincentive contracts focusing on key construction stages with high anticipated congestion. Additional strategies would include police traffic directors, Park-and-Ride or public transit options, public outreach, and website information. Sometimes it is prudent to tolerate higher road user costs for short periods to improve safety, quality, and construction durations. Center work zones, for example, should be avoided whenever possible. Also, surface courses typically last longer when echelon paving is used to reduce the number of cold longitudinal joints. Therefore, longer allowable lane closure hours may be appropriate during final paving operations. Projects with no anticipated queues are considered Low Impact Projects. A Traffic Control Plan will be provided to ensure safe Transportation Operations. The Public Information component will primarily be through contact of applicable local officials, static and variable message signing, and timely web site information. For Moderate and High Impact projects that will have anticipated queues, the Designer shall work with the Project Manager, Traffic Operations, and Road User Solutions to determine if additional strategies and involvement from additional units are required. High Impact Projects are those projects that have traffic demands that exceed work zone capacities for a period of more than six hours per 24 hour day. Moderate Impact Projects are those projects that have traffic demands that exceed work zone capacities for a period of zero to six hours per 24 hour day. Low Impact Projects are those projects that have traffic demands that do not exceed work zone capacities during any time of the 24 hour day. If it is determined that additional strategies are required, the first step is to involve interested parties such as the Designer, Project Manager, Road User Solutions, Federal Highway Administration (FHWA), Traffic Engineering, Construction Services, Freight and Intermodal Coordination, Communications, and Traffic Operations. A current project construction cost estimate and traffic related data from the Feasibility Assessment Report would be evaluated to determine if a Traffic Impact Report is necessary. The report is not necessary if a plan and direction can be agreed upon without it. Traffic Impact Reports, when deemed necessary, may be submitted with the text portion as part of the Preliminary Design Submission. On High Impact projects with complex traffic issues, a separate Traffic Impact Report may be beneficial as determined by the Designer, Project Manager, Traffic Operations, and Road User Solutions. Information in a Traffic Impact Report includes: The existing traffic volumes and capacity data on the roads likely to be substantially impacted. The potential impacts of the construction on traffic through the project and along any detours. (Much of this information should be available from the Concept Development or Feasibility Assessment Report). Project recommendations for traffic mitigation, e.g. nighttime work restricted hours of operation number of lanes available for traffic width of lanes requirements for alternating traffic staging requirements temporary traffic signal timings and restricted turning movements extra widening for better stage construction movable barrier temporary bridge detours or alternate routes for pedestrians, bicyclists, or motorists alternative project delivery methods such as AB Bidding and IncentiveDisincentive contracts temporary traffic signals traffic directors multiple crews pre-cast and pre-fabricated construction advanced utility work real time traffic information project website and public information efforts. Additional project recommendations that go beyond traditional plans and specifications, e.g. park and rides shuttle buses flextime additional transit services interagency coordination with NJ Transit, NJ Turnpike, Port Authority, railroads and utilities hyper-build approaches etc. 8.3.4 Evaluation of Traffic Impact Report At a minimum, the Designer, Traffic Operations, Road User Solutions, and the Project Manager should evaluate the Traffic Impact Report. If applicable, other potentially involved units include the FHWA, Community Relations, Public Education and Marketing, and the Commissioners Office. Road user costs are the result of road user costs per day multiplied by the number of days. Alternatives that cost-effectively reduce these costs are the ones most worth considering. It shall be the Departments responsibility to be aware of nearby construction projects that could further impact traffic. The Program Manager should be aware of how this project and project schedule may be impacted by nearby Capital Program Management, Maintenance, and Access projects as well as projects by other Agencies. 8.3.5 Final Design The components of a good TM plan shall be finalized at this time. The work zone capacities should be maximized to cost effectively minimize work zone congestion. Every effort should be made to avoid having uncontrollable utility work on the critical path of any work stage when volumes exceed capacities. The Traffic Control Plan shall allow for safe and efficient travel through the work zone. Standard closures shall be included in the contract documents based on Department, AASHTO, and MUTCD criteria. The Transportation Operations component must be completed. Allowable lane closure hours should be finalized. Alternative project delivery methods such as AB and ID should be finalized by Road User Solutions, Traffic Operations, the Designer, and Project Manager. The lane occupancy and road user charge values shall be finalized by Road User Solutions and the Designer. These shall be incorporated into the specifications by the Designer and Quality Assurance Team Leader. The Public Information component must be completed. Construction information in regards to lane closures, detours, delays, etc. should be available to the public and linked to the NJDOT commuter information website. Community outreach plans and interagency coordination efforts and plans should be finalized. Compatibility with other construction projects should also be verified. The Plans, Specifications and Estimate (PSampE) for a project may contain Traffic Control Plan requirements in a combination of method and performance based specifications. Method based specifications may consist of a combination of individual and lump sum pay items. Alternatively, performance based specifications may be used. In this option, mobility performance criteria, such as delay, queue length, or travel time through the work zone, may be used. These may be most appropriate for establishing conditions for when contractors desire to increase the allowable lane closure hours available to them to complete their work. 8.3.6 Operations Projects Operations Projects include Permit initiated projects, State contracted work, and In-house Maintenance work. Concept Development and Feasibility Assessment are limited to working with Statewide Traffic Operations to determine allowable lane closures and time frames. Traffic Control Plans are implemented via the standard NJDOT Traffic Control Plans and Specifications. All lane closure schedules and plans are coordinated and approved by Statewide Traffic Operations prior to construction. During construction of Permit-initiated and State contractor projects, In-house staff has the ability to inspect and enforce the proper implementation of traffic control plans to help insure proper set-up and safety. Permit contractors and state contractors follow the minimum criteria for work zone safety guidelines as defined in the current edition of the NJDOT Work Zone Set-Up Guide. In-house maintenance workers must follow the minimum criteria of the Work Zone Set-Up guide and Safety Manual prepared by NJDOT. 8.3.7 Local Aid Projects Local Aid projects will be self-certified to ensure compliance with the NJDOT Work Zone Safety and Mobility Policy. 8.3.8 Construction The safe, efficient, and cost effective construction of the project is the ultimate goal of the project efforts. Work Zone Set-ups shall follow NJDOT Work Zone Safety Set- up Guide, Current Edition (Mobile, Short Duration amp Short Term Stationary Work) Standard Roadway Construction Traffic Control Bridge Construction Details, Current Edition (Intermediate Stationary amp Long Term Stationary Work) MUTCD, Current Edition or a Traffic Control Plan designed and signed by a traffic engineer. All Standards must be maintained throughout the project. Opportunities to reduce congestion via staging modifications or temporary signal timing changes should be considered. Sometimes the construction staging will be affected by traffic mitigation strategies offered by the contractor. If a contractor wants to change any lane closures or times, they must first receive approval through the Resident Engineer and Traffic Operations. Traffic Operations shall seek Road User Solutions assistance when road user cost calculations are required to make a change determination. The Resident Engineer shall keep Traffic Operations and other interested parties informed of construction, scheduling, and lane closures. The website njcommuter shall be the primary means used to provide lane closure information. 8.3.9 Public Information Real time motorist information via static and variable roadway signing, the 511 phone system, Highway Advisory Radio, and the internet (e.g. njcommuter and trips123 ) can provide significant traveler benefits. Advertising campaigns and other marketing strategies may also be necessary for projects with major impacts. Traffic Operations will lead this effort. 8.3.10 Evaluation To effectively manage the traffic mitigation program, the Road User Solutions Unit shall track or gather the following information: Design Values of road user cost calculations for all projects (lane occupancy and road user charges and average delay times) Average delay times and queue lengths based on road user cost calculations Values of all lane occupancy and road user charges used for project specifications Type of project delivery method for all projects Phases of work utilizing alternative project delivery methods such as IncentiveDisincentive and A B Bidding, corresponding dollars per day, and construction phase durations ConstructionTraffic Operations Construction start dates, original Substantial Completion date and adjusted Substantial Completion date Original completion days and actual completion days for any IncentiveDisincentive or B stages in IncentiveDisincentive or A B projects Frequency and duration of contractors closing lanes beyond the allowable lane closure hours or completion dates Lane Occupancy, road user charge, and liquidated damages collected Payment for Incentives Reports of accidents Traffic Control Plan Reviews Annual Traffic Control Plan (TCP) reviews will be initiated by the TCP Review Team Coordinator of Traffic Signal and Safety Engineering. This will consist of multi-disciplinary teams making field visits to project sites throughout the State. The Coordinator will prepare a report on observations and recommendations. Process Review Every two years the Traffic Mitigation Advocate shall meet with the FHWA and other interested parties to assess the effectiveness of the work zone safety and mobility procedures. Lessons learned shall be incorporated into policies, processes, and procedures as necessary to make improvements. 8.3.11 Training All Designers are required to be familiar with work zone safety and mobility strategies, and the application of the Road User Cost manual. Training classes and seminars will be developed on an as needed basis. Construction personnel shall be trained in work zone safety as per Department guidelines. Policy amp Procedure 815 I. PURPOSE To establish a Policy for the consistent and comprehensive application of work zone safety and mobility from planning through construction for Federal-aid highway projects. This policy shall conform to FHWA Final Rule on Work Zone Safety amp Mobility 23 CFR Part 630 Subpart J published in the Federal Register on September 9, 2004. II. DEFINITIONS Federal-aid Highway ndash A highway eligible for assistance under Title 23 United States Code (USC) other than a highway classified as a local road or rural minor collector. Projects on federal-aid highways may be administered by the owner (NJDOT), developers, or other agencies. Highway Workers ndash Highway workers include, but are not limited to, personnel of the contractor, subcontractor, NJDOT, utilities, and law enforcement, performing work within the right-of-way of a transportation facility. Mobility ndash Mobility is the ability to move from place to place and is significantly dependent on the availability of transportation facilities and on system operating conditions. With specific reference to work zones, mobility pertains to moving road users efficiently through or around a work zone area with a minimum delay compared to baseline travel when no work zone is present, while not compromising the safety of highway workers or road users. The commonly used performance measures for the assessment of mobility include delay, speed, travel time, and queue lengths. These are affected by traffic volumes, capacity, and access control. Project Manager (PM) ndash The PM has the responsibility and authority for implementing the Transportation Management Plan (TMP) and other safety and mobility aspects of the project. Public Information (PI) ndash The PI component of the Transportation Management Plan (TMP) includes communication strategies to inform affected road users, the appropriate public entities, area residences and businesses, and the general public about the project and its expected work zone impacts. The PI component varies depending on the project characteristics. It may include such things as information on the project characteristics, expected impacts, closure details, real time traffic information, and commuter alternatives. Safety ndash Safety is a representation of the level of exposure to potential hazards for users of transportation facilities and highway workers. With specific reference to work zones, safety refers to minimizing potential hazards to road users in the vicinity of a work zone and highway workers at the work zone interface with traffic. The commonly used measures for highway safety are the number of crashes or the consequences of crashes (fatalities and injuries) at a given location or along a section of highway during a period of time. Significant Projects ndash Federal-aid highway projects, regardless of funding source, which occupy a location for more than three days with either intermittent or continuous lane closures shall be considered significant. Temporary Traffic Control Plan (TTC) ndash A TTC plan describes TTC measures used for facilitating road users through a work zone or an incident area. The TTC plan plays a vital role in providing continuity of reasonably safe and efficient road user flow and highway worker safety through work zones, or when incidents temporarily disrupt normal road user flow. The TTC plan shall be consistent with the MUTCD, AASHTO Roadside Design Guide, and NJDOT standards. In developing and implementing the TTC plan, pre-existing roadside safety hardware shall be maintained at an equivalent or better level than existed prior to project implementation. The TTC plan shall either be a reference to specific TTC elements in the MUTCD, approved standard TTC plans, or be designed specifically for the project. Traffic Mitigation (TM) ndash Traffic mitigation is the management of motor vehicle, bicycle, and pedestrian traffic to provide work zone safety and reduce user costs. Traffic Mitigation Advocate (TM Advocate) ndash The TM Advocate facilitates the management of TM Policies and Procedures in the Department. Transportation Management Plan (TMP) ndash The TMP consists of strategies to manage the work zone impacts of a project. The scope, content, and degree of detail may vary based on the expected work zone impacts. A complete TMP, required for significant projects, consists of the Temporary Traffic Control Plan (TTC) and addresses the Transportation Operations (TO) and Public Information (PI) components. Transportation Operations (TO) ndash The TO component of the TMP identifies strategies that will be used to mitigate impacts of the work zone on the operation and management of the transportation system within the work zone impact area. Typical TO strategies may include such things as demand management, corridornetwork management, safety management and enforcement, and work zone traffic management. The scope of the TO component varies depending on the project characteristics, and the transportation operations and safety strategies. Work Zone ndash A work zone is an area of a highway with construction, maintenance, or utility work activities. A work zone extends from the first warning sign or TTC device to the End Road Work sign or last TTC device. Work Zone Crash ndash A work zone crash is a traffic crash in which the first harmful event occurs within the boundaries of a work zone or its affected area. This includes crashes occurring on approach to, exiting from or adjacent to work zones. Work Zone Impacts ndash Work zone impacts refer to work zone-induced deviations from the normal range of transportation system safety and mobility. These impacts may extend beyond the physical location of the work zone itself and affect other highway corridors or other modes of transportation. The extent of the work zone impacts may vary based on factors such as road classification, area type (urban, suburban, and rural), traffic and travel characteristics, type of work being performed, time of daynight, and complexity of the project. III POLICY The systematic consideration and management of work zone impacts shall be undertaken, as a minimum, on all federally funded projects and projects that are on the Federal-aid highway system. Work zone impacts and traffic mitigation strategies shall be addressed throughout the various stages of project development. Guidance, procedures, and processes, developed in partnership with the FHWA, will be utilized. The Department is committed to providing a network of transportation facilities that enables the public to move safely and efficiently throughout the State. Developing and maintaining a statewide transportation network requires periodic upgrades and improvements to these facilities through construction projects. The Departmentrsquos first priority is to complete these projects in a timely, cost-efficient, and safe manner. However, it is recognized that construction work zone impacts might inconvenience the public, in some cases resulting in delays, road user costs and disrupted businesses. Work zone impacts are affected by traffic volumes and capacities. Therefore, a volume to capacity analysis should be evaluated for roadways within the project limits affected by the construction to help determine the level of impacts. For significant projects, a Transportation Management Plan (TMP) will be developed to address safety and mobility impacts. For non-significant projects, a TMP may consist of only the TTC plan, although the TO and PI components should be considered as well. Benefits of the TMP for the public and the Department may include: bull Improved motor vehicle, bicycle, and pedestrian traffic flow through the construction area and along detour routes, minimizing disruptions bull Educated public concerning the purpose of and plans for construction projects, helping to reduce citizen complaints and build goodwill for the Department bull Encouraged use of transit and other alternate modes, and travelers educated about the benefits of these modes bull Efficient and timely completion of construction projects, offering short and long term cost savings, while minimizing the disruption for motorists bull Reduced number of incidents in construction corridors bull Enhanced incident detection and emergency response The TMP should be developed in consultation with interested parties. Interested parties may include public officials, local stakeholders, other transportation agencies, utility companies, and transit providers. The extent of the outreach and development will generally increase as the anticipated impacts increase. IV ROLES AND RESPONSIBILITIES The Department as a whole shall provide reasonable, sensible, and responsible work zone safety and mobility for highway workers and the traveling public. Transportation Management Plans are generally multi-dimensional. The plans and TM activities might encompass numerous mitigation strategies, cross municipal boundaries, and require participation of many Departmental Divisions and entities external to the Department, depending on the project impacts and location. Each of these entities must understand its role and responsibilities, the roles of other groups, and how and when the roles interact. The TM Advocate will help develop and maintain policy to provide continuity. The Project Manager will ensure that TMP activities are coordinated from planning through construction. A consistent approach during all project phases should preserve TMP decisions, unless warranted by design changes. The Project Manager will ensure the balance of constructability, schedule, budget, safety, road user impacts, and the community through leadership and collaboration. The work zone safety and mobility goals are to: bull Balance the Departmentrsquos need to minimize roadway construction costs with the need to minimize construction-related inconvenience for motorists, bicyclists, pedestrians, local residents, businesses, and other stakeholders bull Provide a high level of safety for workers and the public bull Ensure that traffic mitigation needs are addressed systematically in all projects bull Provide adequate lead-time for the Department and outside partners to implement traffic mitigation strategies bull Ensure that the cost of traffic mitigation is included in project cost estimates and that funding is provided bull Provide the contractor adequate access to complete the work efficiently while meeting the quality requirements of the contract bull Establish measurable design and construction criteria for the improvement of safety and mobility in the work zone. พระมงกุฎเกล้าเจ้าอยู่หัว AUTHORITY Federal Register, Title 23 Highways, Code of Federal Regulations (CFR), Part 630 ndash Preconstruction Procedures, Subpart J ndash Work Zone Safety and MobilityNew Jersey Department of Transportation Traffic Mitigation Guidelines The Department is committed to providing a network of transportation facilities that enables New Jersey residents, workers, and visitors to move efficiently within and through the State. Developing and maintaining a Statewide transportation network requires that the Department periodically upgrade and improve these facilities through construction projects. The Departments first priority is to complete these projects in a timely and cost-efficient manner. The Department recognizes, however, that construction projects inconvenience motorists traveling through the construction corridors and disrupt businesses located nearby, in some cases resulting in substantial user costs. The safe and efficient flow of vehicles, pedestrians, and bicyclists through roadway construction areas has long been a concern to the Department for its impact on construction operations. Its importance has intensified as motorists, frustrated with the normal levels of congestion they face on ordinary days, have begun to complain about the inconvenience and costs of additional delays caused by roadway reconstruction activities. In addition, businesses complain that nearby construction activities negatively affect their operations and sales. Traffic mitigation (TM) strategies offer benefits to the public, the Department, and other State and local agencies involved in construction projects. TM strategies can improve the flow of traffic through the construction area and along detour routes, minimizing the disruption to motorists and businesses. TM strategies can educate the public about the purpose of and plans for construction projects, helping to reduce citizen complaints and build goodwill for the Department. TM strategies also can encourage motorists to use transit and other alternate modes and educate travelers about the benefits of these modes. Some strategies support efficient and timely completion of construction projects, offering cost savings to the Department and minimizing the duration of disruption for motorists. Finally, TM strategies can reduce the number of incidents in construction corridors via speed incident detection and emergency response to reopen the route. The Department has an interest in realizing traffic mitigation benefits for both itself and the traveling public whenever it is feasible and cost-effective to do so. However, it is difficult to eliminate all construction-related disruption. These Traffic Mitigation Guidelines help provide a customer-oriented approach to the implementation of roadway improvements. These Traffic Mitigation Guidelines were developed following a three-step research process. First, individual and group meetings and interviews were conducted with staff of divisions with an interest or potential role in TM activities, including, but not limited to: Division of Project Management Division of Project Planning and Development Bureau of Traffic Operations Bureau of Traffic Engineering Bureau of Statewide Planning Bureau of Capital Program Support Office of Communications Office of Community Relations NJ Transit The purpose of these meetings was to explore the TM needs of the divisions, identify their existing TM responsibilities and approaches, identify any proposed efforts by the divisions to expand TM activities or improve TM planning, discuss opportunities to address TM within the current project development process, and identify other processes that would increase the visibility of TM in project development. Second, the CPM Procedures Manual and other existing internal documents were reviewed to identify existing application of TM and possible additions that could facilitate more comprehensive consideration and application of TM. Third, the experience of other state transportation departments with TM planning and implementation was reviewed. Following the meetings and review of documents, all divisions agreed that additional written TM guidelines could be useful to the divisions involved in these activities by establishing a formal procedure for integrating TM into project development and serving as a single source summary for how traffic mitigation is considered at each stage of the project planning process. It was agreed that it would be appropriate to prepare a stand-alone TM procedures document that would supplement the CPM Procedures Manual. The guidance would be distributed to all the divisions that have a role or interest in traffic mitigation as an overall framework for integrating traffic mitigation with existing project development activities. It is expected that individual divisions, offices, and bureaus will develop additional instructions to guide their staff in the proper application of TM procedures and responsibilities established for their units. Additionally, it is anticipated that the information in this document would be referenced in the CPM Procedures Manual and addressed in tools used in the project development process, such as Quality Assurance Checklists, Project Scoping Checklists, Quality Assurance and Constructability reviews, Constructability Checklists, and Construction Progress Schedules. This document presents guidance for consistent and comprehensive consideration of traffic mitigation strategies for roadway reconstruction projects implemented by the Department. The objectives of the Traffic Mitigation Policy and Procedures and Guidelines are to: Balance the Departments need to minimize roadway construction costs with the need to minimize construction-related inconvenience for motorists and other stakeholders Ensure that traffic mitigation needs are addressed systematically and consistently in all projects Provide adequate lead-time for Departmental staff and outside partners charged with implementing traffic mitigation strategies to prepare for their responsibilities Maintain high visibility for TM throughout project planning and design Ensure that funding for traffic mitigation is considered early in the planning process and is programmed with design and construction monies Clarify roles and responsibilities for TM These objectives will be accomplished through the implementation of a formal procedure for considering TM needs and options. This procedure will include the following activities, which are defined further in later sections of this document: During Concept Development, identify projects needing TM and the specific TM challenges of those projects In Feasibility Assessment, define an appropriate level of TM needed for each project, based on the expected impacts to road users and businesses, in terms of the expected delay during construction and other factors In Preliminary Design, select and document a set of TM strategies that are likely to meet traffic mitigation goals within TM cost guidelines established for the project Develop a draft TM implementation plan for the project Refine the initial set of TM strategies and the implementation plan as the project becomes more clearly defined through Final Design Finalize the TM plan as design nears completion Implement and evaluate the TM plan The steps outlined above will involve many NJDOT units and outside parties whose expertise is needed or is beneficial for t he development and implementation of TM programs. Traffic mitigation can be multi-faceted, multi-disciplinary, and multi-jurisdictional. These guidelines account for the fact that there is a complex interaction of strategies and partners and provide for coordination and communication among internal and external parties. The balance of this document is divided into five major sections following this introduction: Section 2: Analysis of Need for Traffic Mitigation Describes a process to assess the level of TM needed for a project and estimate order of magnitude costs for TM Section 3: Guidelines for Selecting Traffic Mitigation Strategies Presents a menu of TM strategies and indicates strategies that are appropriate and indicated for various project characteristics. Section 4 : Integration of Traffic Mitigation Within the Existing Project Development Process Describes the approach to integrating TM within project development Section 5: Traffic Mitigation Documentation Describes components of and responsibilities for various TM documents Section 6: Monitoring and Evaluation Presents suggested evaluation measures and procedures for monitoring and evaluating the effectiveness of TM activities Section 7: State-Level Procedures Presents procedures that were created in response to the FHWA Work Zone Rule that identifies three strategic components: Policy, State-Level Procedures, and Project-Level Procedures. Section 8: Project-Level Procedures Presents procedures that were created in response to the FHWA Work Zone Rule that identifies three strategic components: Policy, State-Level Procedures, and Project-Level Procedures. Section 9: Additional Resources Presents websites providing examples and fact sheets. Appendix A: Work Zone Safety and Mobility Policy Presents policy created in response to the FHWA Work Zone Rule. Traffic mitigation decisions are, by necessity, made on a case-by case basis. Each project is unique. The extent and types of traffic mitigation strategies selected for a project will be determined by the characteristics of the project and the site in which it will be located. Additionally, some projects offer special traffic mitigation challenges and some strategies will be better able than others to accomplish these needs. Some projects cause little disruption to motorists and will need nothing more than modest signage to inform motorists that construction is ahead. Other projects, especially those for which substantial travel delays are expected, might require numerous TM strategies, including strategies that divert traffic to alternate routes, provide new travel options, inform a wide audience of travelers about the construction, or alter construction procedures. This section describes the types of project characteristics that can influence TM decisions and offers guidance on how to determine the general level of TM needed for a project and to estimate an order-of-magnitude TM cost. Following this section, guidance is presented for choosing individual TM strategies. The number and mix of strategies included in a traffic mitigation program will depend on many factors, including the scope and duration of the project, the volume of traffic currently using the roadway, characteristics of the construction site, the construction activities that must be accomplished, and the travel alternatives available to motorists. A package of strategies must be chosen that will address the specific challenges for that project. Many project characteristics could influence the need for traffic mitigation and the extent and type of traffic mitigation strategies chosen. Several characteristics are considered to be especially important. These include characteristics related to the level and type of impacts the project is likely to cause to motorists and to members of the community in which the project is located. These primary characteristics should be examined early in the TM process Road User Cost of Staging Impacts to retail business Impacts to neighborhoods Impact on military and emergency response Impacts on access to major activity centers or employers Impacts on localdeveloper projects Constructability Political sensitivity Other characteristics have a less direct relationship to TM but also might be useful to examine to help identify specific TM strategies that could be useful to implement. These secondary characteristics include the following: Duration of construction (months) Number of major construction stages Lane and ramp closures Type of roadway Interstate, State, major arterial Average daily traffic (ADT) volume Seasonal recreational traffic volume increase Expected delay (vehicle hours per day) or queue length (miles) Distance covered by the project Level of urbanization in the construction area Proportion of trucks in the traffic mix Extent of publicmedia exposure Nearby projects influence and impact Maintenance considerations Holidays and schools Road user cost (RUC) is an economic measure of the impact of construction on motorists. It is calculated as the added vehicle operating costs and delay costs borne by highway users as a result of construction projects. These costs are a function of the timing, duration, scope, and characteristics of the construction project, and the volume and operating characteristics of the traffic affected. Road user cost is important in TM because it helps to define an appropriate expenditure for TM activities. A high RUC suggests a greater investment should be made in TM. But RUC also sets an upper limit for the TM investment. In general, the total cost of TM should not exceed the total RUC. 2.3.1 Impacts to Retail Businesses Some construction projects will have a direct impact on retail businesses because they may make the businesses inaccessible, reduce parking areas, or divert traffic away from the businesss locations. Roadway signage can be used to promote these businesses and indicate how they can be accessed. Construction strategies and some traffic control and operations strategies need to be particularly well-planned when businesses are affected, but strategies that reduce the duration of construction could be very appropriate. 2.3.2 Impacts to Neighborhoods Construction projects also can create significant problems for residents in neighborhoods near the construction area. As for business, construction can hinder access and reduce parking. Construction strategies and some traffic control and operations strategies that minimize the flow of traffic through the area andor reduce the duration of construction could be very appropriate. 2.3.3 Impacts on Military and Emergency Response Construction projects can disrupt the ability to respond to emergencies. This should be considered when developing traffic staging plans, temporary detours, or changing access to residential and business areas. 2.3.4 Impacts on Access to Major Activity Centers or Employers Construction areas that pass through or near major activity centers or employment areas can create substantial traffic back-ups, especially at peak travel times. Generally, the more commercial centers and employers are affected by construction, the more TM planning should emphasize public information, construction strategies, alternate routes, and Travel Demand Management (TDM). TDM strategies, such as rideshare incentives, transit improvements, and Park amp Ride lots should receive emphasis when they can be targeted to major employment centers. 2.3.5 Constructability Key characteristic which must be considered early on is the ability to construct a project in the manner envisioned. Soliciting input early on from individuals with construction expertise and the ability to consider abstract ideas in three dimensions are necessary to ensure that the project can be built as planned. 2.3.6 Political Sensitivity Projects with high political sensitivity include those in which lawsuits are underway or threatened, or where political leaders and interest groups are taking highly visible positions either for or against the project. These projects require special emphasis on public information and motorist information. They also might require attention to alternate routes and lane and ramp closures proposed for the construction. Additionally, legislative offices should be kept informed of project progress through legislative liaisons and fax networks. 2.4.1 Duration of Construction (months) The length of time construction is expected to last has a significant impact on both the extent of TM and the types of strategies chosen. Long projects generally can need and can justify a greater number of strategies and more aggressive strategies than can short-duration projects. Although capital improvements might be justified if they provide permanent improvements, large scale and capital intensive strategies are generally used only for large projects. 2.4.2 Number of Major Construction Stages A multi-staged project can create frequent changes in the availability of and accessibility to the roadway, leading to motorist confusion. This suggests a greater emphasis on public and motorist information about scheduled lane and ramp closures. Multi-stage projects also might be appropriate for construction strategies, alternate route, and TDM strategies. 2.4.3 Lane and Ramp Closures The need to close lanes or ramps can increase construction delay significantly. The greater the loss of capacity, the more TM will be needed. In these cases, strong consideration should be given to detours, incident management, and motorist information. Public information about the closures also should be considered to give motorists advance notice of the changes. 2.4.4 Type of Roadway Interstates and State expressways typically warrant more extensive TM than do other roads because of their high traffic volume and critical function in the roadway network. The need to complete construction quickly while maintaining traffic flow suggests strategies that reduce the duration of construction as well as incident management strategies. Because more of the traffic on these roads comes from beyond local areas, motorist information also is likely to be important. 2.4.5 Average Daily Traffic Volume The traffic volume (24 hour7 day) through the corridor has an important influence on the level of TM needed. In general, the higher the volume, the more motorists affected, the greater the total cost of delay, and the greater the justification for TM investment. High volumes suggest the use of incident management, TDM, detours, and public information strategies. 2.4.6 Seasonal Traffic Volume Increase Some highways experience significant increases in travel during certain seasonal recreational periods. If construction is scheduled on these roads during seasonally high volume times, more extensive traffic mitigation strategies could be required than during the lower volume time period. 2.4.7 Expected Delay (vehicle hours per day and per project duration) or Queue Length (miles) Delay is a significant TM characteristic because it is a key measure of the degree of disruption to motorists. Experience suggests that some of the least costly TM strategies for reducing delay over the project period include incident management and contract incentivedisincentive strategies. 2.4.8 Project Distance (miles) The length or breadth of the project can influence the types of traffic mitigation strategies chosen. Projects that extend over a large geographic area might warrant the use of detours and broad-based public information. 2.4 9 Level of Urbanization The level of urbanization frequently is related to the ADT for the roadway. Projects in highly urban areas generally warrant higher levels of TM than do projects in suburban or rural areas and offer opportunities to implement broad-based public information, such as radio ads this outreach is effective because the proportion of traffic that is local is usually high, and motorists can be reached relatively easily with print and electronic media. TDM strategies, such as additional transit and Park amp Ride lots, also are more likely to be useful in urban areas where population densities are greater. 2.4.10 Significant Truck Volume Projects with significant truck volumes can increase the need for TM because they increase vehicle delay. Where truck traffic will be heavy, attention should be focused on construction and detour strategies to divert trucks and on incident management strategies that have the capacity to handle large trucks and load spills. The volume of trucks also can affect the use of and selection of alternate routes. 2.4.11 Public and Media Attention Some projects will attract considerable public and media attention because of the project location, duration, and expected delay. These projects deserve special attention to public information, motorist information, and incident management. 2.4.12 Nearby Projects Consideration of construction planned for parallel routes or other projects in the vicinity is needed. The use of common detour routes may be problematic, so too the exponential increase in congestion caused by two projects along the same corridor. 2.4.13 Maintenance Considerations Snow removal, mowing, and other maintenance duties during construction may complicate projects and detract from the overall traffic mitigation strategy. 2.4.14 Holidays and Schools A special effort should be made to safeguard school bus routes, school crossings, and other needs of school children. Holiday shopping may impact traffic in the corridor and should be considered in the overall traffic mitigation strategy. As a general rule, the extent of expected delay and RUC will be determining factors in the requisite TM level. They are fundamental TM measures because they capture the impacts of other variables, such as the traffic volume, length of construction, and proportion of trucks in the vehicle mix. Frequently, several of the characteristics described above will appear together in a project. For example, long duration projects often are completed in stages and result in extensive cumulative delays projects on high volume roads often result in long delays roads in highly urbanized areas generally carry high traffic volumes and projects with high impacts to businessesemployment centers might be associated with political sensitivity. When multiple TM challenges exist, the level of TM likely should be elevated. In order to best assess traffic impacts, accurate and current traffic data is needed. As such, the Division of Project Planning and Development (DPPD) will acquire 24 hour weekday and weekend truckcar counts for the project area. These should include mainline volumes and, if applicable, side street volumes at signalized intersections and detour routes. Turning movements at key intersections and interchanges shall be provided for peak hour periods. This data shall either be created by, or forwarded to, the Bureau of Transportation Data Development (TDD) which shall maintain a centralized data base of all traffic volume counts. The evaluation of traffic volumes through various work zone capacities and detour routes will help the Designer understand traffic impacts associated with various lane closure alternatives. The Designer will evaluate the alternatives, on a 24 hour basis, to determine when there will be queues. Exhibit 1 shows a sample capacity versus demand chart. Exhibit 1 For evaluation of detours, the detour length and delay times shall be provided by the Designer. The NJDOT Road User Cost Manual provides greater detail in these matters. The number of lanes available in a work zone plays a significant role in the work zone capacity. Work zone capacity charts are in the NJDOT Road User Cost Manual. Basic Work Zone Staging Scenarios in the manual provide the Designer with the ability to quickly evaluate minimum width requirements for various lane closure scenarios. High impact projects are those projects that have traffic demands that exceed work zone capacities for a period of more than six hours per 24 hour day. Moderate impact projects are those projects that have traffic demands that exceed work zone capacities for a period of zero to six hours per 24 hour day. Low impact projects are those projects that have traffic demands that do not exceed work zone capacities during any time of the 24 hour day. The Department recognizes the public does not like to experience traffic delays due to construction. Therefore, the Department should include an alternative that introduces no traffic queues (i.e. volumes are less than capacity) in its evaluation matrix. Common methods to avoid queues are modifying the allowable lane closure hours and utilizing shoulder areas as temporary lanes. In the absence of accurate traffic data or in addition to the quantitative impact analysis, traffic impacts can also be assessed qualitatively. Exhibit 2 provides a worksheet that may be used as a tool to identify impact level for a particular project. It provides space to note details for the primary project characteristics and to note secondary characteristics that might be important in selecting TM strategies. The worksheet also includes a column to indicate the project level suggested by each characteristic individually and defines an overall project impact level drawn from the combination of the levels for various project characteristics. If many of the characteristics, or even a few of the primary characteristics, suggest the project has high impacts, the project likely should be classified at the higher level. Not surprisingly, as the level of impact of the project increases, the level of TM needed and its likely cost also will increase. Exhibit 2 Preliminary Traffic Mitigation Impact Worksheet Overall Impact Assessment 2.5.1 Low Impact Projects The TM needs for low impact projects generally can be adequately addressed by minimal and standard traffic controls used routinely in construction areas. These could include, for example: Fixed signs to alert motorists to the presence of construction activity ahead Traffic cones and temporary barriers to guide motorists through the construction area Low Impact TM Costs Low impact TM projects are generally assumed to have no additional costs beyond those incurred routinely for construction. 2.5.2 Moderate Impact Projects For moderate impact projects, the standard TM strategies used in low impact projects should be applied and augmented. Additional strategies that might be appropriate for these projects could include: Enhanced traffic operations and control strategies, such as construction area screening, variable message signs, reduced travel speeds, temporary parking and turn restrictions, and pavement markings Modest public outreach targeted to residents, businesses, and community centers in the local area affected by the construction: for example, postings on web sites, and fax network for employers and others Detours without additional upgrades to alternate routes Construction activity restrictionsnon-construction increases in capacity (e.g. narrow lanes) to minimize peak period delays Development of incident management plan to reduce delays caused by accidents Modest TDM strategies such as rideshare marketing Moderate Impact TM Costs Moderate impact TM projects rely primarily on strategies, such as public outreach, traffic operations and control, and TDM, which do not require construction of temporary infrastruct ure. These strategies generally have modest cost but may add 15 or more to the construction cost. 2.5.3 High Impact Projects Finally, high impact projects will receive the most aggressive TM strategies. For longer duration projects, more costly strategies could be appropriate due to the high cumulative cost of delay and disruption. Thus, for these projects, some temporary capital improvements might be warranted to maintain capacity. Additionally, it becomes more important to deliver information to the public-at-large and to motorists traveling through the construction area, and to support the needs of businesses for employees and customer access. Therefore, in addition to the strategies noted above for lesser impact projects, critical impact projects might also warrant the following: Advanced traffic operations and control strategies, such as ramp metering, signal adjustments, reversible lanes, lane closure restrictions, and truck restrictions Extensive public outreach to the public-at-large and to targeted groups, including public information meetings, brochures, news releases, media advertising, appearances at community events, a public information center, and a telephone hotline Detours that require capital improvements to alternate routes Temporary capital improvements, such as crossovers, runarounds, temporary roadways, and temporary use of shoulders and median areas to maintain capacity Contracting strategies, such as AB bidding, contractor incentivedisincentive provisions, lane rental provisions, and project consolidation Expanded TDM strategies such as temporary transit service, free bus service, Park amp Ride lots, TDM information, and assistance to employers High Impact TM Costs High impact TM projects generally implement the most aggressive levels of TM strategies. However, in many cases the construction costs for these high impact projects are also high. Therefore, the TM strategies, as a percentage of the construction cost, are typically the same or less than moderate impact projects. Section 2 presented a broad-brush approach to selecting categories of traffic mitigation (TM) strategies. The next step is to select specific strategies sufficient to meet TM goals established for the project. This section presents a menu of TM strategies and guidance for choosing effective and appropriate strategies. The primary purpose of a TM program is to maintain an acceptable level of traffic flow and minimize travel delay experienced by motorists during construction. This is accomplished by reducing the volume of traffic through the construction area, reducing the duration of construction, andor increasing the efficiency with which traffic flows through the area. Many strategies can be used to help meet these objectives. The number and mix of strategies chosen will depend on many factors, including the scope and duration of the project, the volume of traffic currently using the roadway, characteristics of the construction site, the construction activities that must be accomplished, and the travel alternatives available to motorists. A package of strategies must be chosen that will offer the maximum benefit to motorists within an acceptable cost. This section groups TM strategies into six categories, each with a different approach to TM. Individual strategies in each of these categories are described below: Construction and contracting Traffic control and operations Public information Motorist information Travel demand management (TDM) Incident management Construction and contracting strategies are strategies that can be implemented through contract documents during construction. They minimize traffic disruption by shortening the duration of construction andor by ensuring that the maximum number of travel lanes remains open at critical travel periods. Strategies in this category include: Lane constriction Two-way traffic on divided roads Lane closure restrictions Runarounds and crossovers Temporary roadway improvements Project consolidation Lane rental A B bidding IncentiveDisincentive Acceleration Value Engineering Change Proposals 3.2.1 Lane Constriction This strategy reduces the width of one or more lanes to retain a greater number of lanes available to traffic. It should be noted that narrow lane width can reduce the facilitys capacity and average speed, especially where there is significant truck traffic. The use of shoulders can help to reduce the reduction in width. If used for long-term applications, the current lane markings must be hidden and new markings applied to avoid confusing motorists. 3.2.2 Two-Way Traffic on Divided Facility This strategy transfers traffic from a normally divided facility to a two-way operation on one roadway. This strategy requires special consideration in the planning, design, and construction phases. Because of safety concerns, it should be limited to projects in which construction cannot occur without closing lanes and where alternate routes are not available for detours the use of temporary lanes or shoulders is impractical and safety issues can be reasonably addressed. 3.2.3 Lane Closure Restrictions This technique prohibits the contractor from closing lanes during certain days or hours of the day when disruption would cause particular difficulty to motorists or area businesses. If work continues beyond a deadline, a liquidated damage or disincentive payment could be deducted for each hour beyond the end time. A variation on this strategy is to allow lane closures only during nighttime hours. Additional factors should be considered before adopting this measure: noise and light impacts on surrounding communities, traffic impact of detours on surrounding communities, need for special nighttime permits, and worker safety. Nighttime work is most appropriate when traffic volumes drop substantially from day to night andor when a longer continuous period of construction activity is needed. Also, lane closures should be specific to the area of work needed. Excessive lane closure lengths should not be permitted. 3.2.4 Runarounds and Crossovers These strategies involves the total closure of a roadway in one or both directions and rerouting traffic to a temporary roadway constructed adjacent to the roadway and within the ROW or across a median of a divided highway to the opposite lanes. 3.2.5 Temporary Roadway Improvements This strategy can include measures such as temporary use of a shoulder or median area as a travel lane or temporary removal of a median island to provide additional turning lanes at critical intersections. If shoulders are to be used as travel lanes, it might be necessary to upgrade the shoulder to support anticipated traffic loads. 3.2.6 Project Consolidation This strategy promotes the consolidation of multiple, small projects planned for a single roadway or in a corridor to minimize the number of times construction activity must occur. This can be done through a single contract for all the work or individual contracts that are coordinated and scheduled together. This technique should be used during the concept developmentplanning stage, with consideration of projects proposed for completion over several years. To the extent possible, projects should be scheduled for completion within a single construction season. 3.2.7 Lane Rental Provisions This strategy has been successfully employed in other states, but as yet, there is no approved specification in New Jersey. Lane rental provisions encourage contractors to schedule work to minimize lane closure time, to work during the lowest traffic times (when rental rates are lowest), and to be more productive when lanes are closed. In the project bid, the contractor specifies the number of hours lanes will be closed. The total bid is calculated as the actual construction cost plus the number of lane closure hours multiplied by a per hour lane use charge. Fees are charged for hours when lanes are closed and are applied against a lane rental budget included in the contract. If the contractor exceeds the number of hours for lane closures included in the contract, a disincentive payment is assessed against the contractors fee. 3.2.8 A B Bidding A B bidding is a form of cost-plus-time bidding that factors the duration of a construction project into the low price bid. Contractors submit bids comprised of two components: the A component includes the traditional cost of work to be performed under the contract the B component is a bid of the total number of days the contractor estimates are required to complete the identified B portion of the project. The total bid, for award consideration only, is calculated as the A cost plus the B number of days multiplied by a road user cost per day factor. If the contractor exceeds the number of days bid, a liquidated damage is assessed for each day late. This strategy is generally reserved for major impact projects that are of long duration and have multiple-stages or for projects where traffic inconvenience and delays must be held to a minimum or where road user costs are expected to be significant due to heavy current traffic volume long project duration. 3.2.9 IncentiveDisincentive The provision of incentivesdisincentives in the contract afford the contractors the option of working more shifts in order to complete the work quickly, therefore earning an incentive payment for early completion, or of working at a slower pace, using fewer resources, forfeiting the incentive payment, and paying liquidated damages for later completion. A variable completion time may impact the overall traffic mitigation strategy and should be considered. 3.2.10 Acceleration Construction acceleration is a strategy that can be used to minimize traffic impacts by minimizing the duration of the construction impact. By identifying in the bid documents that a specific project is to be completed in a very short duration, contractors are apprised that their bid will need to consider overtime, 247 work, or whatever it takes to get the job done in the minimum time. 3.2.11 Value Engineering Change Proposals (VECP ) This program allows the contractor to offer the State alternatives to the contract documents that are equal or better and provide a cost savings or reduced traffic impacts. The purpose of traffic control and operations devices is to guide motorists clearly and safely up to, through, and around construction areas. Effective traffic control increases safety and capacity and reduces stress for drivers. Some traffic control devices, such as barriers, also play a major role in protecting workers from vehicle crashes. The choice of appropriate traffic control devices is determined by sight distances, traffic speed, volume, and the type of work activity to be performed. Traffic control and operations strategies include: Physical barriers and channelizing devices Temporary reduced speed limit Flashing arrow signs Pavement markings Construction area screening Reversible lanes Alternate routes Signal adjustments Ramp metering Temporary parking and turn restrictions Moveable barrier Truck restrictions 3.3.1 Physical Barriers and Channelizing Devices Physical barriers, such as concrete barriers, cones, and drums that separate traffic from the work area can enhance both motorist and construction crew safety. Additionally, channelizing devices can improve traffic flow by alerting motorists to construction activity ahead and giving them time to react to travel patterns changes. Special attention to snow removal should be considered when using permanent physical barriers. 3.3.2 Temporary Reduced Speed Limit Reducing the maximum allowable speed might be needed or desirable if construction activity or needed TM strategies (e.g. lane closures or lane shifting) could constitute a hazard for motorists. A reduced speed might also be desirable if the normal maximum speed would constitute a hazard for construction workers. 3.3.3 Flashing Arrow Signs These devices can be used to augment conventional traffic control devices where additional warning and directional information is required to control traffic movement through the construction area. 3.3.4 Pavement Markings Pavement markings such as striping, reflective devices, raised pavement markers, and pavement marking arrows can be used to delineate the position of lanes and to designate travel directions. They are especially useful for lane shifting, crossover lanes, and runarounds or other situations in which the usual lanes have been adjusted. 3.3.5 Construction Area Screening Screens that hide construction activity from the view of motorists can prevent gawking and rubbernecking, thus helping to maintain speeds past the construction and reduce the potential for crashes caused by motorist distraction. 3.3.6 Reversible Lanes This strategy is useful when there is strong directional traffic peaking. These lanes require daily lane change set up, however, and thus have limited use. Safety also is a significant issue if the lanes cannot be separated easily by a movable barrier. 3.3.7 Alternate Routes Alternate routes can be used when it is important to close the work area to perform certain construction tasks or when diverting traffic will substantially reduce traffic volumes. These strategies are most appropriate if there is available capacity on routes parallel to the road under construction and the routes can accommodate the mix of vehicles to be diverted. Detour routes might need to be upgraded andor signal timing adjusted to increase capacity or improve traffic flow, making them more attractive to motorists. Coordination with local agencies also is essential. If traffic will be detoured away from the construction, signage will be needed to inform motorists as to where the detour route begins, where it rejoins the road under construction, and where they are to make turns along the detour route. Signage also can be useful on non-turn sections of the detour route to reassure motorists that they are still on the detour and have not missed any turns. 3.3.8 Signal Adjustments Consider changing traffic signal timing if capacity can be increased. Adding or deleting signal phases might be required for changes in travel patterns. Interconnecting traffic signals can help to move traffic through a construction area. 3.3.9 Ramp Metering Traffic flow disruptions can occur at entrance and exit ramps. Ramp metering can be useful where it is necessary to restrict the amount of traffic entering a freeway for capacity or safety reasons. The buildup of queues of vehicles waiting to enter the freeway can have a domino impact for traffic congestion on intersecting roads, however, and must be considered in implementing this strategy. Ramp metering also can divert motorists to alternate routes so adequacy of capacity on nearby roads should be examined. 3.3.10 Temporary Parking and Turn Restrictions One option to increase capacity is to restrict on-street parking, either all day or for peak periods only, to provide for an additional travel lane or to reduce traffic conflicts. It is important to address the concerns of on-street parking for local businesses. Restrictions on turns into driveways and at intersections might be useful or necessary for capacity safety reasons. Restrictions can be during peak periods only or all day. 3.3.11 Moveable Barrier As indicated above in Reversible Lanes the use of moveable barrier may be advantageous, especially if the morning and afternoon peaks have high directional traffic. Moveable barrier should be considered in these situations and provisions for operational costs included. 3.3.12 Truck Restrictions Truck restrictions can increase capacity by both removing some vehicles from the construction area and by increasing the travel speed for the remaining vehicles. It is important with this strategy to identify alternate routes that are suitable for truck traffic. Public information is designed to educate and inform the public about the project, both before it begins and while it is ongoing. It is an essential component of any TM plan and offers several benefits to the project and to motorists. It gives motorists an opportunity to avoid construction sites and frustration and lost time, reduces traffic volumes in the construction area, reduces complaints from drivers who do use the route, and raises public confidence that the Department is well-organized and efficient. Strategies in this group include communication and public outreach tools such as: Fax network Web pages Newsletters and brochures Information letters Community employer meetings News releases media alerts Telephone hotline Paid advertisements and PSAs Posters and billboards Speakers bureau Public information center Highway advisory radio (pre-construction) 3.4.1 Fax Network An effective information strategy in New Jersey is fax network through which information on road, lane, and ramp closures are announced. All eight New Jersey TMAs (Transportation Management Association) provide this service to employers, retail businesses, community groups, libraries, and other organizations who in turn post or distribute the information to employees, customers, and visitors. Some TMAs also provide this information through e-mail to these groups and to individuals who request to be notified. 3.4.2 Web Page The population-at-large is increasingly turning to the internet as a source of information. The Department includes information on a commuter-oriented web page about current and upcoming construction projects, including planned lane closures. Several of New Jerseys TMAs also post construction information on their web pages for projects located in their service areas and provide links to the Department and to other TMAs for information on projects located in other areas. 3.4.3 Newsletters and Brochures Brochures and newsletters are versatile communication tools that can provide information in an attractive, informal format. Both can educate readers about the purpose and benefits of the project, describe the timeline for the work, present tips for avoiding construction, and provide information on TDM services available in the corridor. A map in the brochure or newsletters efficiently conveys the scope of the project, detours, and phases of construction. Newsletters, which are typically larger in size than brochures and frequently have multiple issues, also can carry articles or stories on construction progress. Newsletters and brochures can be useful handouts or mailings for businesses, residents, event planners and community groups but are expensive to produce and become dated quickly. 3.4.4 Information Letters Direct mail is an easy way to communicate with targeted populations, such as businesses, legislators, and local officials, about the project start date. They can be mass-mail form letters or customized to each recipient. 3.4.5 Community Involvement Meetings Public Meetings Employer Meetings Open, public meetings, held both during project development and construction, offer the public an opportunity to learn about the project and ask questions of DOT staff. This strategy can include general meetings or meetings with targeted groups such as businesses, homeowner, and community groups. In the planning and design stages, these meetings can provide DOT with important information for selecting TM strategies. During construction, they can be used to alert the public of construction activities and progress, reducing complaints about traffic disruption. 3.4.6 News Releases Media Alerts The Departments Press Office uses news releases to announce the start and end of all types of projects as well as construction milestones. Primary targets are print and electronic news media and traffic reporters, who can pass the messages on to their audiences, and transportation-related internet web sites. News releases also can be sent to businesses, county and municipal officials, and state and local police. Briefer media alerts can be used to notify newspapers about upcoming temporary construction activities such as lane and ramp closures. Some newspapers will include closure notices in the paper. A round-the-clock toll-free hotline can be established to inform the public about construction schedules, lane or street closures, and transportation alternatives. Tape-recorded messages can be used if they are updated frequently, but personal operators might be appropriate for large projects or to provide return calls for questions that the taped message does not answer. For moderate impact projects, the hotline information service can be included on the Departments existing 1-800-NJROADS hotline. 3.4.8 Paid Advertisements and Public Service Announcements Newspaper and radio advertising and PSAs can be used to convey the main messages of a projects communication plan. They are useful to alert the public that the project will be starting, offer messages about safety in the construction area, and provide information on ridesharing and transit services. For radio ads and PSAs, planning is necessary because ads and PSAs must be scripted, recorded, and distributed. 3.4.9 Posters and Billboards Posters and billboards can be used to announce the start of a major project. Posters may be placed in businesses, public buildings, libraries, community centers, recreational facilities, and other locations that substantial numbers of people visit or pass through. They are most often professionally designed and printed by commercial printers. In view of their high cost, billboards are rarely used, except on heavy volume arterial routes leading to the construction area. They also have limited use because the message must be brief and, over time, motorists have a tendency to ignore them. Planning is very important because billboard leasing must be done in advance and design, printing, and posting are performed by a commercial firm. Smaller, moving billboards also can be placed on the sides of transit buses. 3.4.10 Speakers Bureau This strategy arranges for staff who are knowledgeable about the project to speak to business and community groups, public officials, and the public. Designated speakers can be drawn from Community Relations staff, the Project Manager, the Resident Engineer, Traffic Mitigation Team members, TMAs, and others who are involved with planning and implementation of the TM plan. 3.4.11 Public Information Center A public information center can be established near the construction site. The center can distribute information about the project, display maps of the construction area and mock-ups of the completed project, and provide information about transportation alternatives. As an alternative, Community Relations staff sometimes holds information centers in public spaces during project development. 3.4.12 Highway Advisory Radio (pre-construction) Using low frequency broadcast channels, HAR offers motorists an in-vehicle opportunity to obtain detailed information about future projects in the vicinity and information about alternate routes and other TDM strategies that they could consider using during construction. Information provided to motorists within and in the vicinity of the construction area can alert motorists to delays caused by construction activity and give advance notice of changing operating conditions. The following strategies and tools help to divert traffic to alternate routes during delay periods and improve traffic flow for motorists who remain in the project area: Variable message signs Pre-construction signage Closed Circuit TV (CCTV) Highway Advisory Radio Advance Information Panel Size Variable Message Signs 3.5.1 Variable Message Signs Real-time motorist information provided by VMS play a valuable role in raising awareness and improving safety and traffic flow. VMS can be used for traffic warnings and to alert motorists to upcoming routing changes and lane and ramp closures. They are especially useful where traffic speed drops substantially, significant delays are expected, alignment or surface conditions change, ramps or lanes are closed ahead, or a crash or incident has occurred. VMS used to alert motorists to lane or exit ramp closures might need to be located well in advance of the construction zone or exit if the best alternative route is reached via an earlier exit than the one that is closed or before the start of the construction zone. 3.5.2 Pre-construction Signage Signage can be used prior to the start of construction to inform motorists that construction will be starting. This will help them plan for regular travel through the area during the construction period. These signs, which could be in the form of variable message signs or fixed message signs, can provide a phone number for travel assistance, similar to the POOL number now posted to inform motorists of ridesharing services. 3.5.3 CCTV The need to visually observe and record traffic flow and congestion is critical to the proper management of Variable Message Signs and Highway Advisory Radio. When considering the use of VMS and HAR, the use of CCTV should be considered, as well. 3.5.4 Highway Advisory Radio (HAR) Using low frequency broadcast channels, HAR offers motorists an in-vehicle opportunity to obtain up-to-date, detailed information about current road conditions to supplement information obtained from signage within the construction area. HAR can result in increased diversion of traffic to alternate routes during periods of high volume and during incidents. Fixed or variable message signs alert motorists to the availability and frequency of the radio messages. The adequacy of broadcast quality must be assessed before choosing this strategy. 3.5.5 Advance Information Panel Signs These signs can be used to give motorists information about construction on a different but nearby route. These signs are advantageous where a large number of motorists could be affected by the construction or where it is useful or necessary to inform motorists to avoid a construction area. The objective of travel demand management strategies is to maximize the capacity of the roadway by shifting some motorists from driving alone to multi-occupant modes such as carpools, vanpool, and transit shifting the time at which motorists travel to less congested times and eliminating the need for the trip to be made. Often, TDM strategies implemented by employers and TMA are more effective than those implemented regionally so participation of these partners in the TM plan is highly desirable. TDM strategies include: Rideshare marketing Rideshare incentives and support services Transit incentives and support services Transit service enhancements Park amp Ride lot expansion Employer outreach 3.6.1 Rideshare Marketing The purpose of this strategy, which often is part of a comprehensive public information and outreach campaign, is to encourage motorists who cannot divert to other routes to find others with whom they can carpool or vanpool. It includes such tools as brochures and media advertising promoting ridesharing and informing motorists where they can obtain rideshare matching assistance. 3.6.2 Rideshare Incentives and Support Services Rideshare support services such as ride matching services and Guaranteed Ride Home programs and financial incentives, such as subsidies, discount coupons, or reduced fee carpool parking, can encourage motorists to rideshare rather than drive alone. To be most effective for TM purposes, these strategies must be accompanied by infrastructure strategies, such as Park amp Ride lots, ramp metering that gives preference to carpools and vanpool, and preferential carpool and vanpool parking. The benefits of these strategies can outlive the construction period if some of the motorists who begin ridesharing continue ridesharing after the construction is completed. 3.6.3 Transit Incentives and Support Services Transit support services such as schedule information, Guaranteed Ride Home, on-site sales of transit passes, and financial incentives, such as free or discounted transit and free parking at train stations and Park amp Ride lots can encourage motorists to use transit. As with rideshare strategies, increases in transit ridership that occur during the construction can continue after construction ends. 3.6.4 Transit Service Improvements Increasing the frequency and coverage of transit service in the corridor or on parallel corridors offers motorists new alternatives to driving themselves. If service is operated on the construction route, it can reduce riders frustration over delays. If the service is on a parallel route, it can result in a travel time saving over the time they would have spent traveling along the construction route. Where train service parallels the construction route, shuttle buses from Park and Ride lots to the train stations may be able to divert some traffic from auto to train, improving traffic flow through the construction area. In areas where traffic volume is high, however, it is important to assess whether the rail system has capacity to handle the extra rail riders anticipated and if sufficient rail Park amp Ride lot spaces are available. If rail capacity is available, but Park amp Ride lot capacity is constrained, shuttles from more distant Park amp Ride lots might be appropriate. 3.6.5 Park amp Ride Lot Expansion Improvements to existing lots and the construction of new temporary or permanent lots adjacent to the project corridor can offer convenient meeting places for commuters who are willing and able to rideshare or utilize pick-up points for buses. Because of the cost of construction, this option is most appropriate where Park amp Ride lot capacity is warranted in the absence of the construction and where the new lots are expected to be utilized after construction ends. For temporary lots, spaces might be leased from shopping centers, churches, and other organizations that have primary use of the spaces at times other than during the day. Because numerous tasks, such as identifying, arranging the lease, obtaining insurance, and developing transit links, must be accomplished to institute a temporary lot, planning for this strategy should be started well in advance of the construction start date. 3.6.6 Employer Outreach Employers are important partners in TM efforts because they can have substantial influence over how employees travel to work through incentives they offer and workplace policies they establish. This strategy provides information and assistance to employers to encourage them to implement TDM actions such as telecommuting and flextime that eliminate vehicle trips distributing information about the construction project and TDM options to their employees participating in commute-oriented events and encouraging employees to use alternative modes for commuting. Significant experience with construction projects nationwide has shown that crash rates tend to increase in construction zones because construction activity and unfamiliar and constrained roadway conditions confuse and distract motorists. Some traffic operations and control strategies help to reduce the number of incidents that occur. Incident management strategies are designed to detect and clear incidents quickly. Increased attention to incident management is especially valuable for complex traffic plans with detours and lane closures areas with current high crash rateshigh traffic volumes nighttime construction and projects with a large number of truck movements. Incident management strategies include the following: Incident management plan On-site tow vehicles Enhanced police presence CCTV Traffic monitoring station 3.7.1 Incident Management Plan Event Planning A fundamental TM strategy is a plan for managing and clearing incidents when they occur and for managing traffic around major events occurring in the vicinity of the construction area. An incident management plan typically will define a method to detect incidents quickly establish appropriate diversion routes define the roles assigned to fire, rescue, State and local police, and other emergency response personnel in responding to the incident and define the actions to be taken to clear the incident. Additionally, the plan will identify the location for stores of movable traffic control devices that will be used during an incident and for traffic control during events. Event plans should include the schedule for planned events and traffic control measures to be used. Both incident management plans and event plans must be developed cooperatively with emergency personnel and local officials and agencies within the vicinity of the construction area. 3.7.2 On-Site Tow Vehicles Quick response to incidents is essential to restoring traffic flow one useful strategy is to station tow trucks within the construction area, either all day or during peak periods, to remove disabled vehicles quickly from the area. This strategy should be considered where a crash or breakdown would seriously impair traffic flow and when emergency pull-outs are not available or spaced far apart. 3.7.3 Enhanced Police Presence Police patrols within the construction area can help to ensure that vehicles do not exceed the posted speed limits. On-site, dedicated presence of police also can enhance detection and response to incidents. Additionally, the presence of a parked police vehicle with lights flashing can alert motorists to upcoming construction areas and slow traffic within the area, helping to eliminate crashes and the delays they cause. For large or long-term projects, a traffic monitoring station can provide immediate notification of incidents through closed circuit television and counter loops along the roadway corridor connected though phone lines or communication cables. The detectors also can be useful to measure traffic flow variables as part of an evaluation. It can be difficult to maintain the counters during construction, however, especially if lane shifting is expected. As mentioned earlier, the level of TM applied should be matched to the severity of the travel delay and disruption caused by the project. Too little TM will lead to an unacceptable level of delay and complaints from motorists and businesses. But too much TM will divert resources from other projects. This section explains which groups of strategies are most useful to address various project categories and project characteristics and which individual strategies provide the necessary level of emphasis or aggressiveness for each project category. Table 1 illustrates how project characteristics influence TM strategies. This is intended to suggest which of the six TM strategy areas likely will be needed in the package of TM strategies chosen. Table 2 indicates at which of the four project impact levels various strategies are typically considered, in other words, the level of aggressiveness they are likely to represent. For example, some strategies, such as traffic information fax network, are appropriate for all four levels, while others, such as AB bidding and traffic monitoring station, generally are reserved for high traffic impacts. Table 2 also highlights specific project characteristics, for example, high expected delay or high political sensitivity, that suggest the strategy might be particularly effective needed for a particular project. For example, construction area screening might be particularly needed if the crash rate is expected to increase substantially due to construction activity where lanes must be closed, the roadway has a high ADT, and the project will be of a long duration. Additionally, because the cost of screening is a function of the length of the construction area, the length of the project area might also be a consideration in choosing or not choosing this strategy. Table 1 Potentially Useful Categories of Traffic Mitigation Strategies by Project Characteristic Traffic Mitigation Strategy Categories No alternate route, high traffic volume, long duration, limited project distance, high political sensitivity The preceding sections have described methods and tools the Department can use to assess the need for TM and the level of TM strategies needed. This section describes a more specific discussion of how the Department can integrate these methods and tools into the existing capital project planning process. The Department develops and implements capital projects through a five-phase process: Phase 1 Concept Development Phase 2 Feasibility Assessment Phase 3 Preliminary Design Phase 4 Final Design Phase Phase 5 Construction These phases involve a wide range of planning, analysis, engineering, budgeting, and scheduling activities needed to identify, plan, design, and build roadway improvements. The phases take projects from broad ideas and concepts to final engineering plans that guide construction activities. Each of these phases has a role to play in traffic mitigation. The traffic mitigation activities of each phase are described below, and Exhibit 3 illustrates the basic steps to be accomplished in each of the phases. 4.1.1 Overview of Existing Activities The purpose of Concept Development is to develop and deliver to Feasibility Assessment, a description of well-defined purpose and need and possibly recommend a concept that has been environmentally screened and for which community support has been established. In this first stage of project development, staff will: Identify the transportation problem to be solved, establish its geographic scope, and evaluate the need for the project. Most of this work is preceded with a Tier 2 Screening that may supply this information Identify the Stakeholders Demographics including minority populations and low income populations in the project area Evaluate alternative multi-modal strategies and fulfill CMS requirements Define potential concepts and their limits for short and long-term improvements Identify implementation priorities Define complementary improvement strategies to a highway improvement concept Examine context sensitive designaesthetic opportunities Estimate order of magnitude costs Initiate community involvement with stakeholders, culminating in consensus on the needs and range of solutions In their early exploratory activities, staff perform background research and collect data, such as traffic counts, origindestination distribution, transit availability, travel time data, land use, and other data on characteristics of the roadway, area, environment andor corridor in which the project will be implemented. Next, staff meets with local officials, staff of agencies, and members of the public in the communities affected by the potential project to identify their needs and preferences, and to conduct field research and other studies to define future transportation needs for the area. Third, staff may define one or more conceptual solutions that address the purpose and need, gauge community position, and develop an order of magnitude cost estimate. Staff then compiles all data in the Concept Development report, which is used as the foundation of Feasibility Assessment. 4.1.2 TM Activities in Concept Development At this stage, projects are not well-defined, but some of the project characteristics identified earlier in this paper are known, such as current traffic volumes, crash data, extant substandard roadway features, degree of urbanization, and community impacts. Thus, during Concept Development, it is possible to estimate the impacts likely to be experienced by the public during construction, identify projects that might need or benefit from TM strategies beyond basic traffic control, and propose an initial assessment of the level of TM that might be needed and the general categories of TM strategies that are likely to be effective. Analyze Data on Project Characteristics That Will or Could Influence the Need for TM This step will involve the collection and review of project characteristic data, such as that described in Section 2 of this document. These data will be analyzed to determine the level of traffic and community impacts the project would likely cause. Section 2 offers broad guidelines for defining traffic mitigation levels from project characteristic data. The lead engineer of the Division of Project Planning and Development will fill out the Preliminary Traffic Management Impact Worksheet (Exhibit 2 ) and include it in the Concept Development Report. If a project is determined to be a low impact project, no additional TM activity is required. 4.1.4 Introduce Concepts to Eliminate or Lessen Impacts Community outreach and involvement meetings offer an opportunity to assess the communitys sensitivity to impacts and mitigation options that could gain community acceptance. The Departments Public Involvement Action Plan (PIAP) ensures that communities and other stakeholders are given forums at which projects can be meaningfully discussed. 4.1.5 Identify TM Emphasis Areas At this phase of project development, it is not possible to identify specific TM strategies, but TM emphasis areas will be identified. For example, the areas of emphasis could be secondary use of public information and incident management strategies, with primary use of traffic controls and operations. To the extent that specific strategies within these categories appear to be required or strongly indicated, they should be noted as well. Additionally, project specific needs that are not common to all projects will be noted. These needs will be considered when developing TM strategies related to methods and scheduling of construction. 4.1.6 Document TM Recommendations Finally, the TM recommendations will be documented for use by Scope Development in an Initial TM Assessment. This assessment, which will be prepared for each study, will be included as a chapter in the Concept Development Report and as a TM guide during the Feasibility Assessment. For projects that bypass Feasibility Assessment, the Initial TM Assessment will be provided to the Project Management Group for Preliminary Design. In either case, the Assessment will indicate: Summary of the project characteristics described in Section 2 (Worksheet shown in Exhibit 2 ) with emphasis on the traffic and community impacts of construction Identification of issues for which special TM attention may be warranted Although traffic mitigation needs can be only loosely defined in this phase, examination of TM needs during this early phase is advisable for several reasons. First, introduction of TM into Concept Development permits time for some public input to be solicited as part of the Community Involvement process. Second, some TM strategies require extended lead-time,i.e. addition of NJ Transit bus lines, for development and implementation and should be identified at the earliest possible phase so planning can begin. Third, through community outreach meetings, it will be possible to test early in the process the acceptability of TM solutions to address community impacts. Finally, it is possible that some project concepts would result in unacceptable levels of delay for motorists or other impacts to the community that cannot be cost-effectively mitigated. These impacts then can be included in the analysis and decision-making process conducted through Feasibility Assessment and Preliminary Design. 4.2.1 Overview of Existing Activities During Feasibility Assessment, DPPD performs engineering and environmental analyses and community outreach to determine whether concept alternatives submitted with the Problem Statement can be feasibly evolved into a project. This step is, in essence, a fatal flaw analysis intended to prevent flawed concepts from proceeding to Preliminary Design. It is during this phase that the multi-disciplinary Scope Team is assembled to identify and resolve issues related to the purpose and need developed in Concept Development. The team will discuss alternatives, analyze physical deficiencies, and review the environmental screening. At the end of Feasibility Assessment, DPPD prepares a report that identifies the initially preferred alternative and the rationale for choosing this alternative over the others available, and any outstanding issues in need of resolution. In addition, a Scope Statement for Preliminary Design, which defines the required levels of effort for various design units, is developed. The final steps of this stage are the selection of a recommended alternative and the preparation of the Project Transfer Package that will be submitted to the Division of Project Management. This Package identifies the Recommended Scheme with construction and right-of-way cost estimates documents the public involvement process provides environmental documentation and includes design and cost summaries for any preliminary engineering work performed. 4.2.2 TM Activities in Feasibility Assessment It is during Feasibility Assessment that TM development will begin in earnest. During this stage, traffic mitigation issues will be included in the discussions at Scope Team meetings. In addition, for projects designated as high impact projects, a core Traffic Mitigation Planning Team (TM Team) will be formed as a subset of the Scoping Team. The purpose of the TM Team is to bring together all internal and external entities with a potential role in traffic mitigation activities to ensure that 1) TM planning is consistent across all projects, 2) each involved organization is aware of the TM activities of the others, and 3) TM activities are implemented and coordinated in the most cost-effective manner. At this stage, meetings are conducted to introduce community stakeholders to the alternative recommended to address their problem and to solicit their feedback as to its acceptability. The degree of community involvement varies from one project to another, but all involve some public discussion of both the impacts of the finished project and the costs and impacts experienced during construction. TM Teams also might be established for some moderate impact projects if it appears that multiple strategies will be included. These multiple strategies could necessitate the participation of several outside organizations as well as significant coordination among internal offices. Traffic mitigation for projects with low impacts generally will be addressed sufficiently through Project Scope Meetings held during Feasibility Assessment with minor follow-up of a few internal entities. 4.2.3 Core TM Team Members When the TM Team is first established, it will be comprised of core members, that is, internal and some outside organizations whose involvement is central to the development of the TM plan. Some internal entities will be represented on all TM Teams. During the Preliminary Design phase, the TM Team may be expanded. The core members of the TM Team may include the groups listed below and other interested parties: Division of Project Planning and Development Division of Project Management (Project Manager) Traffic Mitigation Advocate Bureau of Traffic Operations Bureau of Traffic Engineering Bureau of Traffic Signals amp Safety Engineering Bureau of Statewide Planning Office of Communications Community Relations NJ Transit Affected citycounty agencies (e.g. Public Works or Transportation Department) Local Transportation Management Associations TRANSCOM State Police Division of Research and Technology Bureau of ITS Engineering Regional Construction Bureau of Construction Engineering Operations Data Resources Regional Operations Federal Highway Administration The TM Team will have primary responsibility for expanding onadjusting the recommendations included in the Initial TM Assessment prepared during Concept Development. The TM Team will perform three major activities: 1. Define the TM Goals for the Project This step will identify the qualitative and quantitative goals and objectives for the TM program. For example, possible goalsobjectives might be to: Provide work zone speed reductions of 10 mph compared to pre-construction speed limit Reduce traffic volumes by X Decrease average daily traffic by Y vehicles during peak period Maintain LOS D or better Reduce expected delay by Z Keep average delay per vehicle to less than X minutes during the peak period Maintain vehicle-person throughput by increasing auto occupancy and transit ridership Promote public awareness Keep congestion no worse during construction than before Mitigate community impact Maximize safety of workers and the traveling public Keep road user costs below X dollars per day These goalsobjectives serve several purposes. First, they direct TM resources toward the strategies that are most likely to achieve these goals and away from other TM strategies that do not. Second, they focus attention of everyone involved with project development on the expected and desired results. And third, to the extent that the goalsobjectives are quantifiable, they establish targets against which the impacts of possible packages of TM strategies can be assessed during the selection process and provide a measurement standard against which to evaluate the TM effectiveness. 2. Select TM Strategies Next, the project characteristic data will be reviewed to determine, in broad terms, the level of TM (high, moderate, or low) that will be needed to mitigate construction delays and other impacts and to flag concepts for which motoristcommunity impacts during construction might be a fatal flaw. The TM Team will expand on the recommendations provided in the Initial TM Assessment using strategy selection guidance in this document and drawing on their knowledge of the impacts of strategies within their areas of expertise. This initial set of strategies then will be analyzed to determine if it is expected to be sufficient to meet the TM goals established during Feasibility Assessment. This step might require that additional technical analyses, for example, computer simulation of delay or queue length under various conditions of capacity reduction and traffic control, estimates of crash potential, and estimates of trip reduction and route diversion from TDM and public information strategies, be performed. Additional outside research, such as surveyfocus groups, might be considered to estimate the impacts of public information, motorist information, and TDM. If the analysis shows that the initial set of strategies is not sufficient to meet the goals, additional or different strategies should be analyzed, in an iterative process, until one or more TM strategies packages has been identified that will meet the goals. 3. Estimate TM Costs At this point, a preliminary analysis will be undertaken, to estimate the total cost of the package and to compare that cost against the TM benefit to be achieved, with benefit defined as the cumulative road user cost (calculated as defined in the NJDOT Road User Cost Manual ) estimated for the project. Although road user cost does not capture all impacts to all groups, it can serve as a useful starting point when determining an acceptable cost for the TM package. Costs to other stakeholders, such as retail businesses and employers, might also be estimated and considered when determining a total cost for the TM program. The Department might decide that motoristsbusinesses should bear a portion of the cost of the improvement by accepting some degree of delay and disruption. If so, the acceptable TM cost will be proportionately below the road user cost. Road user costs at least should be considered the upper limit on TM program costs. If improvements are required to other facilities, such as road widening or intersection improvements for detours, these may be justified based on road user benefits. If the TM package cost is considered too high relative to the benefits obtained, some TM strategies can be eliminated from the package or replaced with less costly strategies. 4.3.1 Overview of Existing Activities Several significant TM components will occur during Preliminary Design, including refinements to the strategies and development of the Draft TM plan. During the design phase, TM implementation also can begin. It will become the responsibility of the Designer to incorporate into design plans the recommendations for strategies, such as detour routes and temporary roadway improvements that require construction activities. At this same time, the TM Team can begin to plan for implementation of strategies, such as public information and TDM, that are implemented outside the conventional design process. 4.3.2 TM Activities in Preliminary Design 4.3.3 Expand Core TM Team Up to this point, TM planning has been primarily the responsibility of internal staff, with a few outside parties involved as needed. For moderate impact projects, this core TM Team probably will be adequate, but the TM Team almost certainly should be expanded during Final Design at least six to nine months before the start of construction for high impact projects, especially if the project has very high community impacts. The role of these additional members will be to help finalize the TM plan and participate in strategy implementation. Supporting members of the TM Team might include the following: Office of Communications Other transit operators Elected officials of affected citycounty Transportation authorities (e.g. Parkway, Turnpike) Local Police Emergency services Business representatives Activity centers (e.g. arenas, shopping centers) that will experience major impacts Consultants working on TM implementation activities Additionally, for high impact projects, subgroups of the TM Team may be established to focus on specific topics such as traffic operations, public information, and TDM. These subgroups can meet separately from the rest of the TM Team to address issues that relate only to their responsibilities. 4.3.4 Initiate Implementation Planning As noted earlier, some strategies will require long planning, construction, or implementation lead-time. Planning for these strategies should be started during Preliminary Design to ensure they are in place when construction on the main project begins. If local agencies or other groups are to be involved in implementing these strategies, any cost-sharing agreements should be implemented quickly so that the agencies and other groups are given adequate time to complete their responsibilities. 4.3.5 Prepare Draft TM Plan The next TM step will be to develop a draft Traffic Mitigation Plan (TM plan), which will accompany other project documentation into Final Design Development. This TM plan, which will be developed by the core TM Team, will be more detailed than the Initial TM Assessment prepared under Concept Development. It will include the following components: Recap of project characteristics (from Initial TM Assessment) with emphasis on the traffic and community impacts of construction Results of analyses conducted to select TM strategies Detailed description of individual TM strategies selected and their applicationinstallation Approximate TM implementation schedule with critical components noted Responsibilities of the Department, contractor, and other outside parties Detailed estimate of TM costs, sources of funding (if outside contributions will be obtained), and cost-benefit assessment Proposed monitoring and evaluation activities 4.3.6 Estimate TM Costs At this point, a second analysis step will be undertaken, in the same manner as was done during Feasibility Assessment, to refine the cost of the package and to compare that cost against the TM benefit to be achieved. With a more detailed cost analysis, the cost benefit comparison should be re-evaluated if the TM package cost is considered too high relative to the benefits obtained, some TM strategies may be eliminated from the package and replaced with less costly strategies. 4.3.7 Define TM Schedule In this step, a schedule will be developed for implementing TM strategies. The schedule should indicate when strategies will be installed, initiated, or placed into service but also should identify strategies that have long lead-time requirements. These strategies might include improvements to other road facilities strategies for which equipment must be ordered and installed and strategies, such as planning of bus service and construction of Park amp Ride lots, for which implementation requires the assistance of outside partners. 4.4.1 Overview of Existing Activities During Final Design the construction plans are finalized and community relations activities, project budgeting, scheduling, and contractor selection tasks are completed to prepare for the start of construction. 4.4.2 TM Activities in Final Design Development By the time Final Design begins, TM planning is nearly complete. The strategies, costs, and implementation plan should have been developed. During Final Design, the details of the TM plan are refined and solidified to prepare for construction. The major activities that occur for TM during Final Design Development are the following: 4.4.3 Incorporate TM plans during Quality Assurance (QA) Team Review In this step, planned TM strategies also will be included in discussions during Constructability Reviews to ensure that the selected TM strategies are consistent with project phases and efficient construction operation and management, and that no significant constructability issues have been overlooked. 4.4.4 Adjust TM Plan for Design Changes It is expected that the final design plans will closely follow the Project SOW, on which the TM plan is based. It is not uncommon, however, for the SOW to be modified due to some factor that could not be predicted during Scope Development or even during Preliminary Design. These design changes might affect the types or level of effort on one or more of the TM strategies included in the Draft TM plan. The TM planning Team will be consulted if design choices suggest a modification is appropriate or needed. In most cases, these changes will be minor and will be easily incorporated, with small adjustments, into the draft TM plan. But in cases where the design changes are extreme or substantial, it might be necessary to return to the TM strategy selection and analysis process first conducted during Scoping. 4.4.5 Prepare Final TM Plan The next TM step in Final Design is to finalize the TM plan. The Final TM plan, which will be developed by the core members of the TM Team and reviewed by the expanded group, will include similar components to those included in the Draft TM plan. However, a higher level of definition with a focus on what, how, when, and by whom TM activities are to be accomplished is expected. The TM plan will include: Recap of project characteristics Results of analyses conducted to select TM strategies Detailed description of individual TM strategies selected and their applicationinstallation TM implementation schedule with critical components noted Responsibilities of the Department, contractor, and other outside parties Detailed estimate of TM costs and sources of funding (if outside contributions will be obtained) Monitoring and evaluation activities 4.4.6 Review TM Plans during QA Team Review Again, the QA Team will review the planned TM strategies during Constructability Reviews. 4.4.7 Collect Evaluation Baseline Data This TM activity occurs as Final Design is being completed and the start of construction nears. In this step, various members of the TM Team will collect data on current conditions, relevant to the TM strategies in their area, to allow a comparison against the same conditions during the construction process. 4.5.1 Overview of Existing Activities During the Construction phase all components of a Transportation Management Plan should be completed or implemented. 4.5.2 TM Activities during Construction 4.5.3 Preconstruction Conference The final step in the TM plan development process occurs after the construction contractor has been selected, i.e. when the contractor meets with Departmental staff during the preconstruction meeting. Discussion of each phase of work and the provisions to maintain traffic during each phase. The Department should require the contractor to designate a Traffic Control Coordinator responsible, on a 24-hour basis, for TM activities. 4.5.4 Value Engineering Changes to the TM plan proposed by the contractor can be submitted as Value Engineering proposals. The Department is under no obligation to accept the proposed change. Review and consideration of such a proposal will follow the specified VE process. A special attention to commitments made to external stakeholders shall be made in the evaluation of a VE proposal or a change that will affect a TM plan. The VE proposal may need to include public outreach efforts in order to ensure that external stakeholders interests are upheld. The preceding parts of this section described TM activities that occur before construction begins. The majority of these activities cover planning, although some modest implementation, such as construction of Park amp Ride lots, also can occur during these pre-construction stages. During construction, the emphasis shifts to implementation of TM strategies, following the TM plan finalized in Final Design, and the evaluation of the effectiveness of the strategies in meeting TM goals. As construction proceeds, it is possible that some adjustment of TM strategies might be needed. For example, a mid-project evaluation could show that the implemented strategies were not having the desired results or were unnecessary or underutilized. This might suggest that new strategies or modified versions of the existing strategies should be implemented during construction. For this reason, TM Team members responsible for strategy implementation and evaluation will monitor strategy performance and review results of interim evaluations and recommend strategy adjustments to the TM Team and the Project Manager. Further, it is possible that the project itself could change during construction, for example, to incorporate VE proposals submitted by the contractor or due to other factors unrelated to the performance of the existing TM strategies. In such cases, the TM Team will assess the impact of the changes on the appropriateness and likely effectiveness of the TM strategies implemented previously and will make recommendations to the Project Manager. These recommendations could include modifications to the TM strategies. Alternatively, if the project changes would require TM strategies that conflict with agreements made with external stakeholders, the TM Team could instead recommend that the proposed project changes not be implemented. The traffic management strategies to be applied during a project must be documented along the development process to establish a point of reference for subsequent steps and, ultimately, to guide implementation of the strategies. The Traffic Mitigation Guidelines, which has focused attention primarily on those projects for which significant TM activities will be necessary, has mentioned several required TM documents. These documents are summarized here, along with guidance regarding when they are needed and the components to be included. Three primary documents will be prepared for TM activities: Initial TM Assessment, Draft TM plan, and Final TM plan. These documents will be prepared during Concept Development, Initial Design Development, and Final Design, respectively. Each will be progressively more detailed than the previous document as the details of the project become more certain and the TM strategies more defined. It is important to note that the level of TM documentation needed for a project will vary, depending on the level of TM to be applied. It is important that TM concepts be considered for all projects however, many projects will have little or no TM impact - - it is not the Departments intent to expend resources on documentation when it is not needed. The following is a discussion of the use and components of the three documents, along with an indication of the projects for which these reports will be prepared. 5.1.1 Initial TM Assessment TM recommendations defined during Concept Development will be documented in the Initial TM Assessment. This assessment report will be included as a chapter in the Concept Development Report, part of the package to be provided to Scope Development. The purpose of the Assessment is to identify the likely need for TM and the project issues that affect the need for TM. The Assessment will include the following sections: Summary of the project characteristics described in Section 2 of this document (TM Impact Worksheet shown in Exhibit 1) with emphasis on the traffic and community impacts of construction Identification of issues for which special TM attention may be warranted A TM Assessment will be prepared for each project concept, but the level of detail and the length of the report will vary with the level of project impact. The Assessment prepared for a low impact project is likely to be very short with little more than a brief explanatory attachment to the Preliminary Project TM Impact Worksheet shown in Exhibit 1. Assessments for projects with more significant levels of TM impact will be more substantive as they need to provide more detailed guidance for TM consideration in Scope Development. 5.1.2 Prepare Draft TM plan The second TM document to be prepared is the Draft TM plan, which will be prepared during Preliminary Design. This Draft TM plan will be developed by the TM Team, with various members of the team preparing individual sections of the plan that relate to their areas of expertise. The Project Management Group will be responsible for coordinating TM plan development. The TM plan will be more detailed than the Initial TM Assessment and will include the following components: Introduction Brief description of the project (location, project needobjectives, and proposed improvements) Project Characteristic - Recap of project characteristics (from Initial TM Assessment) with emphasis on the traffic and community impacts of construction Analysis Results - Results of analyses conducted to select TM strategies, including delay simulations, estimate of road user costs, analyses of strategy effectiveness, public surveys, crash rate simulations, and any other analyses TM Strategies - Detailed description of individual TM strategies selected and discussion of how they will be appliedinstalled. TM strategies are to be grouped into three categories: Public Information, TDM, and Operations (including strategies for construction and contracting, traffic control and operations, motorist information, and incident management). Implementation Schedule - Approximate TM implementation schedule with planning and implementation milestones noted for critical components Planning and Implementation Responsibilities - Responsibilities to be performed by the Department, contractor, and other outside parties TM Costs - Detailed estimate of TM costs, sources of funding (if outside contributions will be obtained), and cost-benefit assessment Evaluation Outline of proposed monitoring and evaluation activities A Draft TM plan will be established for all high impact projects. A TM plan will be developed for moderate impact projects that include some or several of the following characteristics: High traffic volume for the type of roadway Significant detrimental impacts on mobility for local or through traffic Significant reduction in capacity through lane, ramp, or intersection closures Alternate routing will be necessary Timing will negatively affect activity centers or other events held within the corridor Significant impact on local communities and businesses 5.1.3 Prepare Final TM plan The third TM document is the Final TM plan. This TM plan also will be developed by the core members of the TM Team and will be reviewed by members of the expanded TM Team, if additional members have been added beyond the core membership. The Final TM plan will be organized in the same manner as the Draft TM plan and include similar components to the Draft TM plan. The Final TM plan will reflect any design changes made during Design Development and a higher level of definition of each plan component, with a particular focus on implementation: how, when, and by whom TM plan activities will be accomplished. The specific components of the Final TM plan will include: Introduction Brief description of the project (location, project needobjectives, and proposed improvements) Project Characteristic Recap of project characteristics with emphasis on the traffic and community impacts of construction Analysis Results Results of analyses conducted to select TM strategies, including delay simulations, estimate of road user costs, analyses of strategy effectiveness, public surveys, crash rate simulations, and any other analyses TM Strategies Detailed description of individual TM strategies selected and discussion of how they will be appliedinstalled Implementation Schedule Approximate TM implementation schedule with planning and implementation milestones noted for critical components Planning and Implementation Responsibilities Responsibilities to be performed by the Department, contractor, and other outside parties TM Costs Detailed estimate of TM costs and sources of funding (if outside cont ributions will be obtained) Evaluation Definition of the evaluation measures to be used to evaluate TM effectiveness and a detailed description of the monitoring and evaluation activities to be performed, including baseline data collection, surveys to be conducted, traffic counts, delay measurement, crashincident tracking, and any other evaluation activity. The Final TM plan will be provided to all members of the TM Team, other Departmental entities with an interest need to be informed of the planned TM activities, outside parties that will participate in implementation, and the contractor performing the construction. If any design changes are made during construction that affect any part of the TM plan, Construction shall inform the Traffic Mitigation Advocates Office. 5.1.4 References to Traffic Mitigation in Other Project Planning Documents The purpose of this document is to present a broad framework for incorporating TM planning and implementation into the existing capital projects planning process. It is expected that individual NJDOT units will develop additional instructions to guide their staff in the proper application of TM procedures and responsibilities established for their units. Additionally, the procedures described in this document are to be referenced in the CPM Procedures Manual and addressed in tools used in the project development process, including Quality Assurance Checklists for Initial and Final Design Project Scoping Checklists Quality AssuranceConstructability Reviews Constructability Checklists and the Construction Progress Schedule. Once construction has begun, it is important to monitor the progress and use of individual strategies, track the costs of the strategies, and evaluate their effectiveness in mitigating impacts caused by the construction. Monitoring will allow fine-tuning of strategies - - adjusting or augmenting them if they are not producing the necessary and desired results. For example, ridership counts on temporary transit vehicles might show that buses are underutilized suggesting additional marketing might be needed. Alternatively, the counts might show that the buses are very crowded suggesting additional bus runs should be operated. Similarly, monitoring of delay time on alternate routes might indicate that revised signal timing or additional police enforcement will be needed to use these routes most effectively. Evaluation of the successes and problems encountered also will provide feedback to guide the development of traffic mitigation activities for future projects and help avoid future problems. Although no two projects are completely alike, many similarities will exist across projects. Results of the traffic mitigation findings of one project will be useful input to the development of TM plans and the allocation of TM resources for other projects. TM plan evaluations will focus on the performance of both individual TM strategies and overall performance of the construction corridor or facility. Evaluation should be based on measures of effectiveness that are tied to the TM goals set for the project and use methodologies and measuring tools generally recognized and accepted in the discipline covered by the evaluation. Various evaluation measures are appropriate for assessing corridor and strategy performance. This section suggests key measures and associated measuring methods. Various Departmental units will have a role in collecting and interpreting evaluation data. The Traffic Mitigation Policy document identifies these units and the TM strategies they will be responsible for evaluating. Baseline data will be collected prior to the start of construction, and most evaluation data will be collected during the construction phase of the project however, for some evaluation activities, post-construction evaluation also might be appropriate, as noted below. 6.1.1 Evaluation Measures Corridor performance is the bottom line of evaluation. Key evaluation measures for both construction facilities and alternate routes include: Traffic volumes (within the corridor and on parallel routes) Traffic flow (LOS, delay time, length of delay period) Vehicle occupancies Bicycle and pedestrian traffic in corridor Crash rates and severities and incident frequency Project durationacceleration These measures should be assessed regularly during construction and be assessed for both peak and off-peak times. Measurements should be made before, during, and after construction to examine short- and long-term impacts. For TM plans for high impact projects, evaluation also should track at least some of these measures on non-affected corridors of similar type of roadway for control purposes in order to rule out the effects of exogenous factors, such as gasoline prices, on the observed results. 6.1.2 Data Collection Methods Various methods can be used to evaluate corridor performance. Standard machine counting or video procedures can be used to make traffic counts. Several methods can be used to estimate vehicle occupancy. Direct observation is the most direct and accurate method to measure occupancy in slow-moving traffic. Another method is to include occupancy questions in a standard origin and destination survey which is mailed to users of the construction facility who have been identified through license plate monitoring. It can be difficult, however, to obtain a sample that is representative of the total traffic population. Past experience with response rates and confidence levels should determine the necessary sample size for statistical confidence. 6.2.2 Evaluation Measures Some construction strategies can be evaluated by comparison with conditions prior to implementing the strategy and with conditions on similar facilities without the strategies in place. For example, lane and ramp closures and two-way traffic on divided highways can be evaluated based on traffic, delay, and accident conditions prior to and after implementation, taking care to control for beforeafter factors through a non-construction, control facility of similar type and traffic. Controls are important as traffic volumes and accident rates can change for other reasons, especially if the project extends over several years. Contract management strategies such as A B bidding can be evaluated by comparing project or phase duration to the anticipated projected schedule and the time it took to complete similar projects or phases in other areas. Lane rental can be evaluated similarly, by comparing the number of hours lanes were projected to be closed to the actual number. When evaluating incentives and disincentives, it is important to estimate all possible benefits and costs. For example, the potential of finishing the project early must be tempered by other factors, such as delay and crash risk. If large delays results from a fast track approach, these negative effects must be considered in the evaluation as well. 6.2.3 Data Collection Methodologies The mechanisms for evaluating travel impacts of lane and ramp closures and two-way traffic on divided highways are similar to those for tracking general corridor performance, as noted earlier in this Section. Standard machine counting or video procedures can be used to make traffic counts. Vehicle occupancies can be measured by direct observation or video, and through surveys, as noted before. VMT can be assessed through survey questions asking about trip length. The same cautions about sample size also apply here. Delay and speeds can be measured through floating or test car procedures. 6.2.4 Traffic Control and Operations 6.2.5 Evaluation Measures As with construction strategies, many traffic control strategies can be evaluated by comparison with conditions prior to implementing the strategy and with conditions on similar facilities without the strategies in place. Reversible lanes, ramp metering, and truck restrictions, for example, can be evaluated based on volume of traffic, delay, and accident conditions prior to and after implementation. Other strategies, such as temporary reduced speed, barriers and channelizing devices, and construction area screening also can be measured through assessment of delay speed also can be used to assess the effectiveness of these strategies. Strategies that affect routes off the corridor, such as ramp metering, alternate routes, and temporary parking restrictions, potentially affect not only the construction route but also parallel routes, in essence relocating traffic congestion. Therefore, similar evaluation measures of delay, volume, and speed on these routes also should be measured. Typical measures evaluated for these strategies include: Traffic volumes and peak traffic counts (construction and parallel routes) Vehicle throughput Vehicle occupancy counts Bicycle and pedestrian traffic in construction area Travel delay and travel time Crash rates 6.2.6 Data Collection Methodologies Data collection tools for traffic control and operations are similar to those used to measure the overall corridor performance. These include standard machine counting or video procedures for traffic counts direct observation and occupancy questions on surveys to assess vehicle occupancy and timed runs in a floating or test car to assess travel time or average travel speed. For channelizing devices, reduced speed limits, and flashing arrow signs, direct observation of motorist behavior might be most useful to determine the degree to which travel change is occurring. Video recording also could be useful to determine to what degree traffic is slowing or diverting as requested. Observation over longer periods of time can be used to reveal patterns of change, such as times of heavy traffic vs. light traffic conditions or daytime vs. nighttime behavior. 6.2.8 Evaluation Measures Public information serves two purposes in traffic mitigation. First, it informs the public about the purpose of the project and generates and maintains public support for the project. Second, it encourages changes in travel behavior during the project to minimize delay and accidents. The principal objectives of public information monitoring are to determine 1) is the public getting accurate information and 2) is the information changing travel behavior Evaluation measures that can be used to determine the availability and accuracy of information generally focus on identifying the sources used by the public to obtain information and the perceptions they form toward various aspects of the project. For example, typical evaluation measures might include: Percentage of public-at-large and motorists in corridor who are aware of the project Motorists perception of the reason the road is under construction Percentage of public-at-large and motorists in corridor who are aware of alternate routes and alternate modes of travel Sources (brochures, traffic reports, news articles, etc.) used by motorists to learn about the project Public perceptions regarding clarity, availability, and usefulness of information Number of requests for information (web site hits, customer service phone calls, etc.) For the second objective, change in travel behavior can be measured by Percentage of motorists in the corridor who change their time of travel or their route Number of travelers who rideshare in the corridor Number of travelers who bicycle or walk in the corridor Transit load factorsridership in the corridor compared to a pre-construction baseline 6.2.9 Data Collection Methodologies Determining how well information is distributed and understood can be established by tracking the number of information requests and the level of media attention, and by conducting surveys and focus groups with members of the public-at-large and with the motorists who use the corridor. Telephone survey and mail-out surveys can be directed toward travelers identified through license plate monitoring. Another method is the repeat panel, in which a group of travelers is periodically surveyed on their awareness throughout the project. Surveys can be used to determine any changes in motorist behavior as a result of the information. Travelers who respond to awareness surveys can be grouped by their level of awareness to determine if those with higher awareness levels were more likely to change their travel patterns. Another method is to ask those making travel changes why they have done so, what sources of information they received, and what information relative to other factors influenced their decision. Questions about both awareness and behavioral change must be structured carefully. Questions should begin by tapping unprompted recollection of messages and information about the project. When recollection has been established, additional questions can be used to probe specifically about the sources of information, perceptions formed as a result of the information, and the helpfulness of the information. 6.2.10 Motorist Information 6.2.11 Evaluation Measures Motorist information strategies, including signing and highway advisory radio, can be evaluated on the same basis, and by using some of the same evaluation measures, as for public information. Here, however, the first evaluation objective is whether or not motorists are aware of the information transmitted and whether the information is useful to specific on-road decisions they are making while they are in the construction corridor. 6.2.12 Data Collection Methodologies Two appropriate evaluation methods include a survey of motorists in the corridor and direct observation of motorist behavior. As with evaluation of public information strategies, mail or telephone surveys can be targeted to travelers using the corridor. Questions can be asked about whether the motorist tuned in to the highway advisory radio or if they noticed the variable message signs. Questions also can be asked about how travelers responded to the information received. Follow up questions might be asked of motorists who said they did not hear advisory radio or read the sign. For example, they could be asked if they did not know about the radio or did not believe the information would be useful. Motorists who use the HAR could be asked about the message content, accuracy (considering current conditions), and length. For variable message signs, evaluation might focus on patterns of sign recognition to determine effectiveness. Perhaps signs highlighted with arrow boards get higher recognition than those that do not. Evaluation also could ask about motorists lane location to determine if they were able to see and read the signs clearly from various lanes. Another method to evaluate effects of motorist information is through observation. Presuming the requested behavior change is relatively soon after the message, observers can determine the degree to which travel change is occurring. Video recording also could be useful to determine to what degree traffic is slowing or diverting as requested. Observation over longer periods of time and some weeks after message signs have been installed can be used to reveal patterns of change, such as daytime vs. nighttime behavior or times of heavy traffic vs. light traffic conditions. 6.2.13 Demand Management 6.2.14 Evaluation Measures The effectiveness of TDM strategies can be measured indirectly through improvements to traffic flow but, in general, they are measured through usage and the number of vehicles they remove from the construction corridor. To determine vehicle reduction, it is necessary to identify the previous mode used for travelers who are using rideshare modes and transit. It is important, however, not to assume that every non-SOV traveler is new to that mode. Some alternate mode users will have been using an alternative before construction began. For example, the implementation of temporary bus service can attract some travelers who were previously carpooling. Other measures of TDM success are the share of travelers using alternative modes and the average occupancy of vehicles using the corridor. Typical evaluation measures for TDM strategies include: Train and bus ridership Number of new carpools and vanpools Alternative mode share, vehicle occupancy Park amp Ride lot usage Number of requests for rideshare information 6.2.15 Data Collection Methodologies Various methods can be used to determine the effect of TDM strategies on corridor performance. One way to measure the effectiveness of general ridesharing campaigns is to survey a sample of rideshare applicants following a promotion in order to determine if the campaign, or a specific incentive provided in the corridor, influenced the applicant to submit an application or to change modes. Specific new services, such as transit enhancements and Park amp Ride lots, can be measured through ridership or usage counts. Additionally, on-board or intercept surveys can be used to identify prior mode, trip length, and other variables related to vehicle trip reduction and VMT reduction. Employer-based TDM actions also might be assessed to determine the contribution of telecommuting and other employer actions to vehicle trip reduction. The usual tool for assessing employer program effectiveness is an employee survey in which current travel patterns and previous travel patterns are compared. The result of the survey is an assessment of the reasons for any changes in patterns. 6.2.16 Incident Management 6.2 17 Evaluation Measures The key strategies included in incident management are designed to detect and respond to accidents. Thus, incident management should be evaluated on the basis of how well it reduces response and removal time for accidents and incidents. Incident frequency also might be measured if it is measured over a long period of time or measured against comparable incident rates for equivalent-type, non-construction corridors. Evaluation measures for these strategies could include: Number of accidentsincidents Ratio of incidents per traffic volume within construction zone to other freeways Incident responseclearance time Delay time during incidents 6.2.18 Data Collection Methodologies Incident detection is more difficult to measure than response time because the actual moment the incident starts can be difficult to assess. Detection can be measured most easily where video surveillance records an accident or shoulder stop. By providing a real time basis for the incident and by reviewing logs of the State Police and other emergency services, it is possible to determine how long after the actual incident the detection occurred. Response and removal time can be assessed by comparing the log time of the incident detection with the arrival on the scene, as recorded by the police or responding emergency service, and the time at which the roadway is cleared of the incident, again as recorded on police logs. The State-Level Processes and Procedures provide a systematic approach for addressing and managing the safety and mobility impacts of work zones. The safe and efficient flow of vehicles, pedestrians, and bicyclists through construction work zone areas is a major Department concern. Its importance has recently been echoed by the Federal Highway Administration as is evidenced in the September 9, 2004 rulemaking on Work Zone Safety and Mobility. All states are to be in compliance with this Rule by October 12, 2007. This document addresses the program level procedures, and works in conjunction with the Work Zone Safety and Mobility Policy, the Work Zone Safety and Mobility Project-Level Procedures, the Traffic Mitigation Guidelines, and other Department procedures. 7.3.1 Traffic Mitigation Advocate The TM Advocate manages TM Policies and Procedures to ensure that the Departments traffic mitigation goals of safety and mobility are realized. The position of Traffic Mitigation Advocate has been established under the Assistant Commissioner of Capital Program Management. The Traffic Mitigation Advocate is responsible for overseeing: Work Zone Policy amp Procedure Development amp Implementation Work Zone Assessment and Management Work Zone Data Evaluation Work Zone Safety and Mobility Training Programs Work Zone Safety and Mobility Process Review Additionally, the Traffic Mitigation Advocate will strive for continuity of TM strategies from Concept Development through Construction, as projects are transferred from one phase to the next. The TM Advocate should have the following qualifications and skills: Understanding of a great range of TM techniques Knowledge of project delivery schedules and alternate project delivery methods Understanding of activities of major NJDOT units with a role in traffic mitigation and the project delivery process Sensitivity to the needs of the traveling public and impacted communities, and an ability to build acceptable balanced solutions Understanding of project management tools and techniques used by Capital Program Management, such as road user costs, cost estimating, value analysis, and design decision tools The TM Advocate will also play a supportive role in traffic mitigation areas led by the Subject Matter Experts and will: Review Department procedures manuals, design guides, standard specifications, and other applicable documents and incorporate the details of the adopted TM Policy and Procedures into these documents where applicable Modify Traffic Mitigation Policy and Procedure s as needed to adapt to any modifications to the current project delivery process and update to reflect current industry practices or innovative strategies Address, as necessary, Traffic Mitigation related procedures for Operations and Maintenance, Local Aid, and permit construction projects 7.3.2 Work Zone Assessment and Management The TM Advocate will assist the lead unit responsible for a specific project delivery phase by: Serving as a subject matter expert and advisory on traffic mitigation topics and as an advocate for developing and implementing programmatic traffic mitigation strategies throughout the project delivery process. The Advocate will serve to resolve conflicts between units during concept development, project scoping, design, and construction. Assisting Project Manager to facilitate and coordinate TM activities conducted by other units and assist with the preparation of draft and final TM plans. Maintaining on-going dialogue with other transportation agencies to ensure that traffic mitigation strategies are considered for all transportation facilities impacted by all transportation projects and that project schedules are coordinated among agencies to avoid unnecessary conflicts. Assisting Local Aid, and Maintenance and Operations to make recommendations for traffic mitigation strategy. 7.3.3 Work Zone Data Evaluation Field observations will include utilizing the latest available traffic information to help determine the impacts to traffic. If shoulders or lane closures are proposed that will generate queues, road user cost calculations may be performed to determine the operational impacts in terms of average travel delays. Work Zone Set-ups shall follow Department standards. In addition, only NCHRP 350 approved safety items will be considered acceptable. Historical work zone crash data shall be maintained and evaluated for possible work zone safety improvements. 7.3.4 Work Zone Safety and Mobility Training Construction and work zone personnel shall be trained in work zone safety as per Department guidelines as it relates to implementation, operation, inspection, and enforcement. Designers shall be provided with guidelines and standards to properly develop safe and efficient work zones. Periodic training updates that reflect changing industry practices and Department processes and procedures shall also be provided. The Project-Level Procedures provide guidance and identify key steps to be addressed on individual projects from Planning through Construction to ensure work zone impacts are managed in accordance with the Work Zone Safety and Mobility Policy. Work zone safety and mobility impacts will vary depending on the work zone, location, duration, and roadway capacities and volumes. The responsible parties involved vary with the subject matter and the project phase: Traffic Mitigation Advocate Exhibit 4 outlines key steps involved in the development of a Transportation Management Plan to address work zone safety and mobility concerns. Exhibit 4 Work Zone Safety and Mobility Key Steps The Transportation Management Plan should be developed with input from stakeholders and interested parties. The extent of this outreach will generally increase as the anticipated impacts increase. Stakeholders may include public officials, police, fire, schools, emergency medical services, other transportation agencies, transit providers, utilities, business communities, and other interested parties. Traffic mitigation efforts are required during each major project development phase. The units involved will change as the project evolves from Planning through Construction. The key units involved in planning, project development, design, and construction shall consistently and comprehensively apply traffic mitigation strategies to provide safe, efficient, cost effective work zones for both construction and the traveler. Any questions or comments in regards to policies or procedures should be directed to the Traffic Mitigation Advocate. Each unit has their own procedures that are continually being refined. Many topics discussed here have procedures that are contained elsewhere by other units. The procedures shall be supported and supplemented by, but not limited to, the following documents: Work Zone Safety and Mobility Policy NJDOT Work Zone Safety and Mobility State-Level Procedures NJDOT Road User Cost Manual NJDOT Traffic Mitigation Guidelines FHWA Work Zone Rule -23 CFR Part 630, September 9, 2004 NJDOT Work Zone Set-Up Guide NJDOT Capital Project Procedures. Design Manual. Specifications. Construction Details, and Sample Plans Road user costs tend to become significant when the traffic volumes exceed capacity. Road user costs exist due to any delays, whether work zone related or not. As an example, Exhibit 5 shows the cost of a one minute delay for 10,000 vehicles. Traffic mitigation strategies should be considered when the benefits of reduced road user costs exceed the increased construction and related mitigation costs. In work zones, the NJDOTs Road User Cost Manual values are the differential road user costs of added vehicle costs and delay costs created by the queues and reduced speeds caused by the work zone. Clearly, road user costs can be significant. When comparing design and construction costs to road user costs, the road user costs should typically be weighted within the range of 10-25 of the calculated road user cost value. บันทึก . Values based on 2006 cost rates. To calculate costs for 20,000 vehicles per day, multiply costs by two. To calculate costs or two minute delay, multiply costs by two. Capital Program Management procedures are outlined below. The Operations and Local Aid groups have their own procedures that follow the Work Zone Safety and Mobility Policy and State-Level Procedures guidelines. 8.3.1 Concept Development (Feasibility Assessment if Pipeline 1 or 2 project) The analysis of traffic volumes and capacities is foundational for the development of traffic mitigation strategies. The Division of Project Planning and Development (DPPD) shall acquire 24 hour weekday and weekend truckcar counts for the project area. These should include mainline and detour route volumes and, if applicable, side street volumes at signalized intersections. Turning movements at key intersections and interchanges shall be provided for peak hour periods. This data shall either be created by, or forwarded to, the Bureau of Transportation Data Development (TDD) which maintains a centralized data base of all traffic volume counts. 8.3.2 Feasibility Assessment The evaluation of traffic volumes through various work zone capacities and detour routes will help the Designer understand traffic impacts associated with various lane closure alternatives. The Designer will evaluate the alternatives on a 24 hour basis to determine when there would be queues. Exhibit 6 shows a sample Capacity versus Traffic Demand chart. The Departments Subject Matter Expert is the Road User Solutions Unit from the Bureau of Smart Solutions amp Value Management. Exhibit 6 Capacity versus Traffic Demand Illustration For evaluation of detours, the average detour length and delay times shall be determined by the designer. The NJDOT Road User Cost Manual provides greater detail in these matters. The number of lanes available in a work zone plays a significant role in the work zone capacity. Work zone capacity charts are in the NJDOT Road User Cost Manual. Basic Work Zone Staging Scenarios in the manual provide the designer with the ability to quickly evaluate minimum width requirements for various lane closure scenarios. The Department recognizes the public does not like to experience traffic delays due to construction. Therefore, in its evaluation matrix, the Department should include an alternative that introduces no traffic queues (i.e. volumes are less than capacity). Common methods to avoid queues are modifying the allowable lane closure hours and utilizing shoulder areas as temporary lanes. If this no congestion scenario can be cost effectively accommodated and becomes the initially preferred alternative, the work zone will have Low Impacts. 8.3.3 Preliminary Design For projects that will have anticipated queues, the Designer shall utilize the NJDOT Road User Cost Manual to provide a preliminary analysis of the actual road user costs. There are a multitude of traffic mitigation strategies that are available. Depending on the project location and severity of the anticipated impacts, different strategies will be appropriate and the most cost effective. Mitigation strategies may be temporary in nature or provide permanent improvements. Typical strategies include limited lane closure hours, shoulders as lanes, liquidated damages for lane occupancy and road user charges, intelligent transportation services (ITS) including real time traffic information, movable barrier, temporary roads and bridges, temporary traffic signals, detours, accelerated construction, pre-cast items, and A B or IncentiveDisincentive contracts focusing on key construction stages with high anticipated congestion. Additional strategies would include police traffic directors, Park-and-Ride or public transit options, public outreach, and website information. Sometimes it is prudent to tolerate higher road user costs for short periods to improve safety, quality, and construction durations. Center work zones, for example, should be avoided whenever possible. Also, surface courses typically last longer when echelon paving is used to reduce the number of cold longitudinal joints. Therefore, longer allowable lane closure hours may be appropriate during final paving operations. Projects with no anticipated queues are considered Low Impact Projects. A Traffic Control Plan will be provided to ensure safe Transportation Operations. The Public Information component will primarily be through contact of applicable local officials, static and variable message signing, and timely web site information. For Moderate and High Impact projects that will have anticipated queues, the Designer shall work with the Project Manager, Traffic Operations, and Road User Solutions to determine if additional strategies and involvement from additional units are required. High Impact Projects are those projects that have traffic demands that exceed work zone capacities for a period of more than six hours per 24 hour day. Moderate Impact Projects are those projects that have traffic demands that exceed work zone capacities for a period of zero to six hours per 24 hour day. Low Impact Projects are those projects that have traffic demands that do not exceed work zone capacities during any time of the 24 hour day. If it is determined that additional strategies are required, the first step is to involve interested parties such as the Designer, Project Manager, Road User Solutions, Federal Highway Administration (FHWA), Traffic Engineering, Construction Services, Freight and Intermodal Coordination, Communications, and Traffic Operations. A current project construction cost estimate and traffic related data from the Feasibility Assessment Report would be evaluated to determine if a Traffic Impact Report is necessary. The report is not necessary if a plan and direction can be agreed upon without it. Traffic Impact Reports, when deemed necessary, may be submitted with the text portion as part of the Preliminary Design Submission. On High Impact projects with complex traffic issues, a separate Traffic Impact Report may be beneficial as determined by the Designer, Project Manager, Traffic Operations, and Road User Solutions. Information in a Traffic Impact Report includes: The existing traffic volumes and capacity data on the roads likely to be substantially impacted. The potential impacts of the construction on traffic through the project and along any detours. (Much of this information should be available from the Concept Development or Feasibility Assessment Report). Project recommendations for traffic mitigation, e.g. nighttime work restricted hours of operation number of lanes available for traffic width of lanes requirements for alternating traffic staging requirements temporary traffic signal timings and restricted turning movements extra widening for better stage construction movable barrier temporary bridge detours or alternate routes for pedestrians, bicyclists, or motorists alternative project delivery methods such as AB Bidding and IncentiveDisincentive contracts temporary traffic signals traffic directors multiple crews pre-cast and pre-fabricated construction advanced utility work real time traffic information project website and public information efforts. Additional project recommendations that go beyond traditional plans and specifications, e.g. park and rides shuttle buses flextime additional transit services interagency coordination with NJ Transit, NJ Turnpike, Port Authority, railroads and utilities hyper-build approaches etc. 8.3.4 Evaluation of Traffic Impact Report At a minimum, the Designer, Traffic Operations, Road User Solutions, and the Project Manager should evaluate the Traffic Impact Report. If applicable, other potentially involved units include the FHWA, Community Relations, Public Education and Marketing, and the Commissioners Office. Road user costs are the result of road user costs per day multiplied by the number of days. Alternatives that cost-effectively reduce these costs are the ones most worth considering. It shall be the Departments responsibility to be aware of nearby construction projects that could further impact traffic. The Program Manager should be aware of how this project and project schedule may be impacted by nearby Capital Program Management, Maintenance, and Access projects as well as projects by other Agencies. 8.3.5 Final Design The components of a good TM plan shall be finalized at this time. The work zone capacities should be maximized to cost effectively minimize work zone congestion. Every effort should be made to avoid having uncontrollable utility work on the critical path of any work stage when volumes exceed capacities. The Traffic Control Plan shall allow for safe and efficient travel through the work zone. Standard closures shall be included in the contract documents based on Department, AASHTO, and MUTCD criteria. The Transportation Operations component must be completed. Allowable lane closure hours should be finalized. Alternative project delivery methods such as AB and ID should be finalized by Road User Solutions, Traffic Operations, the Designer, and Project Manager. The lane occupancy and road user charge values shall be finalized by Road User Solutions and the Designer. These shall be incorporated into the specifications by the Designer and Quality Assurance Team Leader. The Public Information component must be completed. Construction information in regards to lane closures, detours, delays, etc. should be available to the public and linked to the NJDOT commuter information website. Community outreach plans and interagency coordination efforts and plans should be finalized. Compatibility with other construction projects should also be verified. The Plans, Specifications and Estimate (PSampE) for a project may contain Traffic Control Plan requirements in a combination of method and performance based specifications. Method based specifications may consist of a combination of individual and lump sum pay items. Alternatively, performance based specifications may be used. In this option, mobility performance criteria, such as delay, queue length, or travel time through the work zone, may be used. These may be most appropriate for establishing conditions for when contractors desire to increase the allowable lane closure hours available to them to complete their work. 8.3.6 Operations Projects Operations Projects include Permit initiated projects, State contracted work, and In-house Maintenance work. Concept Development and Feasibility Assessment are limited to working with Statewide Traffic Operations to determine allowable lane closures and time frames. Traffic Control Plans are implemented via the standard NJDOT Traffic Control Plans and Specifications. All lane closure schedules and plans are coordinated and approved by Statewide Traffic Operations prior to construction. During construction of Permit-initiated and State contractor projects, In-house staff has the ability to inspect and enforce the proper implementation of traffic control plans to help insure proper set-up and safety. Permit contractors and state contractors follow the minimum criteria for work zone safety guidelines as defined in the current edition of the NJDOT Work Zone Set-Up Guide. In-house maintenance workers must follow the minimum criteria of the Work Zone Set-Up guide and Safety Manual prepared by NJDOT. 8.3.7 Local Aid Projects Local Aid projects will be self-certified to ensure compliance with the NJDOT Work Zone Safety and Mobility Policy. 8.3.8 Construction The safe, efficient, and cost effective construction of the project is the ultimate goal of the project efforts. Work Zone Set-ups shall follow NJDOT Work Zone Safety Set- up Guide, Current Edition (Mobile, Short Duration amp Short Term Stationary Work) Standard Roadway Construction Traffic Control Bridge Construction Details, Current Edition (Intermediate Stationary amp Long Term Stationary Work) MUTCD, Current Edition or a Traffic Control Plan designed and signed by a traffic engineer. All Standards must be maintained throughout the project. Opportunities to reduce congestion via staging modifications or temporary signal timing changes should be considered. Sometimes the construction staging will be affected by traffic mitigation strategies offered by the contractor. If a contractor wants to change any lane closures or times, they must first receive approval through the Resident Engineer and Traffic Operations. Traffic Operations shall seek Road User Solutions assistance when road user cost calculations are required to make a change determination. The Resident Engineer shall keep Traffic Operations and other interested parties informed of construction, scheduling, and lane closures. The website njcommuter shall be the primary means used to provide lane closure information. 8.3.9 Public Information Real time motorist information via static and variable roadway signing, the 511 phone system, Highway Advisory Radio, and the internet (e.g. njcommuter and trips123 ) can provide significant traveler benefits. Advertising campaigns and other marketing strategies may also be necessary for projects with major impacts. Traffic Operations will lead this effort. 8.3.10 Evaluation To effectively manage the traffic mitigation program, the Road User Solutions Unit shall track or gather the following information: Design Values of road user cost calculations for all projects (lane occupancy and road user charges and average delay times) Average delay times and queue lengths based on road user cost calculations Values of all lane occupancy and road user charges used for project specifications Type of project delivery method for all projects Phases of work utilizing alternative project delivery methods such as IncentiveDisincentive and A B Bidding, corresponding dollars per day, and construction phase durations ConstructionTraffic Operations Construction start dates, original Substantial Completion date and adjusted Substantial Completion date Original completion days and actual completion days for any IncentiveDisincentive or B stages in IncentiveDisincentive or A B projects Frequency and duration of contractors closing lanes beyond the allowable lane closure hours or completion dates Lane Occupancy, road user charge, and liquidated damages collected Payment for Incentives Reports of accidents Traffic Control Plan Reviews Annual Traffic Control Plan (TCP) reviews will be initiated by the TCP Review Team Coordinator of Traffic Signal and Safety Engineering. This will consist of multi-disciplinary teams making field visits to project sites throughout the State. The Coordinator will prepare a report on observations and recommendations. Process Review Every two years the Traffic Mitigation Advocate shall meet with the FHWA and other interested parties to assess the effectiveness of the work zone safety and mobility procedures. Lessons learned shall be incorporated into policies, processes, and procedures as necessary to make improvements. 8.3.11 Training All Designers are required to be familiar with work zone safety and mobility strategies, and the application of the Road User Cost manual. Training classes and seminars will be developed on an as needed basis. Construction personnel shall be trained in work zone safety as per Department guidelines. Policy amp Procedure 815 I. PURPOSE To establish a Policy for the consistent and comprehensive application of work zone safety and mobility from planning through construction for Federal-aid highway projects. This policy shall conform to FHWA Final Rule on Work Zone Safety amp Mobility 23 CFR Part 630 Subpart J published in the Federal Register on September 9, 2004. II. DEFINITIONS Federal-aid Highway ndash A highway eligible for assistance under Title 23 United States Code (USC) other than a highway classified as a local road or rural minor collector. Projects on federal-aid highways may be administered by the owner (NJDOT), developers, or other agencies. Highway Workers ndash Highway workers include, but are not limited to, personnel of the contractor, subcontractor, NJDOT, utilities, and law enforcement, performing work within the right-of-way of a transportation facility. Mobility ndash Mobility is the ability to move from place to place and is significantly dependent on the availability of transportation facilities and on system operating conditions. With specific reference to work zones, mobility pertains to moving road users efficiently through or around a work zone area with a minimum delay compared to baseline travel when no work zone is present, while not compromising the safety of highway workers or road users. The commonly used performance measures for the assessment of mobility include delay, speed, travel time, and queue lengths. These are affected by traffic volumes, capacity, and access control. Project Manager (PM) ndash The PM has the responsibility and authority for implementing the Transportation Management Plan (TMP) and other safety and mobility aspects of the project. Public Information (PI) ndash The PI component of the Transportation Management Plan (TMP) includes communication strategies to inform affected road users, the appropriate public entities, area residences and businesses, and the general public about the project and its expected work zone impacts. The PI component varies depending on the project characteristics. It may include such things as information on the project characteristics, expected impacts, closure details, real time traffic information, and commuter alternatives. Safety ndash Safety is a representation of the level of exposure to potential hazards for users of transportation facilities and highway workers. With specific reference to work zones, safety refers to minimizing potential hazards to road users in the vicinity of a work zone and highway workers at the work zone interface with traffic. The commonly used measures for highway safety are the number of crashes or the consequences of crashes (fatalities and injuries) at a given location or along a section of highway during a period of time. Significant Projects ndash Federal-aid highway projects, regardless of funding source, which occupy a location for more than three days with either intermittent or continuous lane closures shall be considered significant. Temporary Traffic Control Plan (TTC) ndash A TTC plan describes TTC measures used for facilitating road users through a work zone or an incident area. The TTC plan plays a vital role in providing continuity of reasonably safe and efficient road user flow and highway worker safety through work zones, or when incidents temporarily disrupt normal road user flow. The TTC plan shall be consistent with the MUTCD, AASHTO Roadside Design Guide, and NJDOT standards. In developing and implementing the TTC plan, pre-existing roadside safety hardware shall be maintained at an equivalent or better level than existed prior to project implementation. The TTC plan shall either be a reference to specific TTC elements in the MUTCD, approved standard TTC plans, or be designed specifically for the project. Traffic Mitigation (TM) ndash Traffic mitigation is the management of motor vehicle, bicycle, and pedestrian traffic to provide work zone safety and reduce user costs. Traffic Mitigation Advocate (TM Advocate) ndash The TM Advocate facilitates the management of TM Policies and Procedures in the Department. Transportation Management Plan (TMP) ndash The TMP consists of strategies to manage the work zone impacts of a project. The scope, content, and degree of detail may vary based on the expected work zone impacts. A complete TMP, required for significant projects, consists of the Temporary Traffic Control Plan (TTC) and addresses the Transportation Operations (TO) and Public Information (PI) components. Transportation Operations (TO) ndash The TO component of the TMP identifies strategies that will be used to mitigate impacts of the work zone on the operation and management of the transportation system within the work zone impact area. Typical TO strategies may include such things as demand management, corridornetwork management, safety management and enforcement, and work zone traffic management. The scope of the TO component varies depending on the project characteristics, and the transportation operations and safety strategies. Work Zone ndash A work zone is an area of a highway with construction, maintenance, or utility work activities. A work zone extends from the first warning sign or TTC device to the End Road Work sign or last TTC device. Work Zone Crash ndash A work zone crash is a traffic crash in which the first harmful event occurs within the boundaries of a work zone or its affected area. This includes crashes occurring on approach to, exiting from or adjacent to work zones. Work Zone Impacts ndash Work zone impacts refer to work zone-induced deviations from the normal range of transportation system safety and mobility. These impacts may extend beyond the physical location of the work zone itself and affect other highway corridors or other modes of transportation. The extent of the work zone impacts may vary based on factors such as road classification, area type (urban, suburban, and rural), traffic and travel characteristics, type of work being performed, time of daynight, and complexity of the project. III POLICY The systematic consideration and management of work zone impacts shall be undertaken, as a minimum, on all federally funded projects and projects that are on the Federal-aid highway system. Work zone impacts and traffic mitigation strategies shall be addressed throughout the various stages of project development. Guidance, procedures, and processes, developed in partnership with the FHWA, will be utilized. The Department is committed to providing a network of transportation facilities that enables the public to move safely and efficiently throughout the State. Developing and maintaining a statewide transportation network requires periodic upgrades and improvements to these facilities through construction projects. The Departmentrsquos first priority is to complete these projects in a timely, cost-efficient, and safe manner. However, it is recognized that construction work zone impacts might inconvenience the public, in some cases resulting in delays, road user costs and disrupted businesses. Work zone impacts are affected by traffic volumes and capacities. Therefore, a volume to capacity analysis should be evaluated for roadways within the project limits affected by the construction to help determine the level of impacts. For significant projects, a Transportation Management Plan (TMP) will be developed to address safety and mobility impacts. For non-significant projects, a TMP may consist of only the TTC plan, although the TO and PI components should be considered as well. Benefits of the TMP for the public and the Department may include: bull Improved motor vehicle, bicycle, and pedestrian traffic flow through the construction area and along detour routes, minimizing disruptions bull Educated public concerning the purpose of and plans for construction projects, helping to reduce citizen complaints and build goodwill for the Department bull Encouraged use of transit and other alternate modes, and travelers educated about the benefits of these modes bull Efficient and timely completion of construction projects, offering short and long term cost savings, while minimizing the disruption for motorists bull Reduced number of incidents in construction corridors bull Enhanced incident detection and emergency response The TMP should be developed in consultation with interested parties. Interested parties may include public officials, local stakeholders, other transportation agencies, utility companies, and transit providers. The extent of the outreach and development will generally increase as the anticipated impacts increase. IV ROLES AND RESPONSIBILITIES The Department as a whole shall provide reasonable, sensible, and responsible work zone safety and mobility for highway workers and the traveling public. Transportation Management Plans are generally multi-dimensional. The plans and TM activities might encompass numerous mitigation strategies, cross municipal boundaries, and require participation of many Departmental Divisions and entities external to the Department, depending on the project impacts and location. Each of these entities must understand its role and responsibilities, the roles of other groups, and how and when the roles interact. The TM Advocate will help develop and maintain policy to provide continuity. The Project Manager will ensure that TMP activities are coordinated from planning through construction. A consistent approach during all project phases should preserve TMP decisions, unless warranted by design changes. The Project Manager will ensure the balance of constructability, schedule, budget, safety, road user impacts, and the community through leadership and collaboration. The work zone safety and mobility goals are to: bull Balance the Departmentrsquos need to minimize roadway construction costs with the need to minimize construction-related inconvenience for motorists, bicyclists, pedestrians, local residents, businesses, and other stakeholders bull Provide a high level of safety for workers and the public bull Ensure that traffic mitigation needs are addressed systematically in all projects bull Provide adequate lead-time for the Department and outside partners to implement traffic mitigation strategies bull Ensure that the cost of traffic mitigation is included in project cost estimates and that funding is provided bull Provide the contractor adequate access to complete the work efficiently while meeting the quality requirements of the contract bull Establish measurable design and construction criteria for the improvement of safety and mobility in the work zone. พระมงกุฎเกล้าเจ้าอยู่หัว AUTHORITY Federal Register, Title 23 Highways, Code of Federal Regulations (CFR), Part 630 ndash Preconstruction Procedures, Subpart J ndash Work Zone Safety and Mobility
Bdo -forex- อัตรา วันนี้
เรียกร้อง -forex- สูญเสีย ภาษี ผลตอบแทน