Consider the geometric and traffic characteristics shown below. Approach (Width) Peak hour Approach Volumes: North (56 ft) South East West (56 ft) (68 ft) (68 ft) Left Turn Through Movement Right Turn Conflicting Pedestrian Volumes PHF For the following saturation flows: 165 105 200 166 442 395 585 538 172 167 201 210 900 1,200 1,200 900 0.95 0.95 0.95 0.95 Through lanes: 1,600 veh/h/In Through-right lanes: 1,400 veh/h/In Left lanes: 1,000 veh/h/In Left-through lanes: 1,200 veh/h/In Left-through-right lanes: 1,100 veh/h/In The total cycle length was 289 s. Now assume the saturation flow rates are 10% higher, that is, assume the following saturation flow rates: Through lanes: 1,760 veh/h/In Through-right lanes: Left lanes: Left-through lanes: Left-through-right lanes: 1,540 veh/h/In 1,100 veh/h/In 1,320 veh/h/In 1,210 veh/h/In Determine a suitable signal phasing system and phase lengths (in s) for the intersection using the Webster method. (Enter the sum of green and yellow times for each phase, and afterwards the total cycle length. Ensure that enough green time is provided to allow for pedestrian movement. Assume each of the four approaches is divided into a left lane, a through lane, and a through-right lane. Assume the lost time due to acceleration and deceleration during each phase is 3.5 seconds, and the time lost due to the red clearance interval between each phase is 1.5 seconds. Also, assume the curb-to-curb distance is 56 ft when pedestrians travel during the N-S phases and 68 ft when pedestrians travel during the E-W phases. Finally, assume pedestrians walk at a speed of 3.5 ft/s through a crosswalk of width 10 ft.) Phase 1: N-S left turn Phase 2: N-S through & through-right turn S S Phase 3: E-W left turn Phase 4: E-W through & through-right turn Total cycle length S S S ---Select--- increased What effect does the increase in saturation flow rates have on cycle length? decreased By increasing saturation flow rates by 10%, the recommended total cycle length ---Select--- by| %.

Consider the geometric and traffic characteristics shown below. Approach (Width) Peak hour Approach Volumes: North (56 ft) South East West (56 ft) (68 ft) (68 ft) Left Turn Through Movement Right Turn Conflicting Pedestrian Volumes PHF For the following saturation flows: 165 105 200 166 442 395 585 538 172 167 201 210 900 1,200 1,200 900 0.95 0.95 0.95 0.95 Through lanes: 1,600 veh/h/In Through-right lanes: 1,400 veh/h/In Left lanes: 1,000 veh/h/In Left-through lanes: 1,200 veh/h/In Left-through-right lanes: 1,100 veh/h/In The total cycle length was 289 s. Now assume the saturation flow rates are 10% higher, that is, assume the following saturation flow rates: Through lanes: 1,760 veh/h/In Through-right lanes: Left lanes: Left-through lanes: Left-through-right lanes: 1,540 veh/h/In 1,100 veh/h/In 1,320 veh/h/In 1,210 veh/h/In Determine a suitable signal phasing system and phase lengths (in s) for the intersection using the Webster method. (Enter the sum of green and yellow times for each phase, and afterwards the total cycle length. Ensure that enough green time is provided to allow for pedestrian movement. Assume each of the four approaches is divided into a left lane, a through lane, and a through-right lane. Assume the lost time due to acceleration and deceleration during each phase is 3.5 seconds, and the time lost due to the red clearance interval between each phase is 1.5 seconds. Also, assume the curb-to-curb distance is 56 ft when pedestrians travel during the N-S phases and 68 ft when pedestrians travel during the E-W phases. Finally, assume pedestrians walk at a speed of 3.5 ft/s through a crosswalk of width 10 ft.) Phase 1: N-S left turn Phase 2: N-S through & through-right turn S S Phase 3: E-W left turn Phase 4: E-W through & through-right turn Total cycle length S S S ---Select--- increased What effect does the increase in saturation flow rates have on cycle length? decreased By increasing saturation flow rates by 10%, the recommended total cycle length ---Select--- by| %.

Traffic and Highway Engineering

5th Edition

ISBN:9781305156241

Author:Garber, Nicholas J.

Publisher:Garber, Nicholas J.

Chapter8: Intersection Control

Section: Chapter Questions

Problem 8P

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