Studies have shown that the traffic flow on a single-lane approach to a signalized intersection can be described by the Greenshields model with a capacity of 1800 veh/h. 1) If the jam density on the approach is 120 veh/mi, determine the velocity of the stopping wave when the approach signal changes to red, if the approach traffic flow has the space mean speed of 40 mi/h 2) At the end of the red interval, how many vehicles stopped from the stop line if the red interval is 30 sec?

Studies have shown that the traffic flow on a single-lane approach to a signalized intersection can be described by the Greenshields model with a capacity of 1800 veh/h. 1) If the jam density on the approach is 120 veh/mi, determine the velocity of the stopping wave when the approach signal changes to red, if the approach traffic flow has the space mean speed of 40 mi/h 2) At the end of the red interval, how many vehicles stopped from the stop line if the red interval is 30 sec?

Traffic and Highway Engineering

5th Edition

ISBN:9781305156241

Author:Garber, Nicholas J.

Publisher:Garber, Nicholas J.

Chapter6: Fundamental Principles Of Traffic Flow

Section: Chapter Questions

Problem 15P

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TRANSPORTATION ENGINEERING-TRAFFIC SIGNALS" Recent analysis at an approach to pre-time signalized intersection indicate that the volume-to-capacity ratio (v/c) is 0.8, htat saturation flow rate (s) is 1600 vehicles/hour, and the effective green time is 50 seconds. If the average delay, assuming D/D/1 is 11.25 seconds per vehicle, determine the arrival flow rate (vehicles/hour) and the cycle length.
c) Assume that traffic on a single-lane approach to a signalized intersection observes the Greenshield's speed-density relationship. The jam density on the approach is 180 veh/mile and free flow speed is 60mph. Suppose the current signal is green and the traffic is moving at 40mph and passing through the intersection. After the green time ends, the signal turns red and vehicle queue starts to build up. The signal keeps red for 60 seconds and turns green again. Answer the following questions: 1. How fast does the vehicle queue build up after the signal turns red? 2. How far the vehicles are queued in upstream, i.e. the maximum queue length?
Assume that traffic on a single-lane approach to a signalized intersection observes the Greenshield’s speed-density relationship. The jam density on the approach is 180 veh/mile and free flow speed is 60mph. Suppose the current signal is green and the traffic is moving at 40mph and passing through the intersection. After the green time ends, the signal turns red and vehicle queue starts to build up. The signal keeps red for 60 seconds and turns green again. Answer the following questions: 1. How fast does the vehicle queue build up after the signal turns red? 2. How far the vehicles are queued in upstream, i.e. the maximum queue length?
Traffic arrives at an approach of a signalized intersection at a flow rate of 360 veh/h. The approach receives 30 seconds effective green time in a 60 second cycle. The departure rate during effective green is 900 veh/h. Assume D/D/1 queuing at this approach, analyze traffic operation at this approach and provide statistics to quantify traffic operation
The southbound approach of a signalized intersection carries a flow of 1000 veh/h/ln at a velocity of 50 mi/h. The duration of the red signal indication for this approach is 15 sec. If the saturation flow is 2000 veh/h/ln with a density of 75 veh/ln, the jam density is 150 veh/mi, determine the following: a. The length of the queue at the end of the red phase b. The maximum queue length c. The time it takes for the queue to dissipate after the end of the red indication.
An approach to a signalized intersection has a saturation flow rate of 1800 veh/h. At the beginning of an effective red, there are six vehicles in the queue and vehicles arrive at 900 veh/h. The signal has a 60- second cycle with 25 seconds of effective red. What is the total vehicle delay after one cycle (assume D/D/1 queuing)?
Traffic on the eastbound approach of a signalized intersection is traveling at 40 mi/h, with a density of 44 veh/mi/ln. The duration of the red signal indication for this approach is 30 sec. If the saturation flow is 19500 veh/h/In with a density of 51 veh/mi/ln, and the jam density is 120 veh/mi/ln, determine the following: 6-11 (a) The length of the queue at the end of the red phase (b) The maximum queue length (c) The time it takes for the queue to dissipate after the end of the red indication.
4) Traffic on the eastbound approach of a signalized intersection is traveling at 35 mi/hr, with a density of 46 veh/mi/In. The duration of the red signal indication for this approach is 30 sec. If the saturation flow is 1900 veh/h/In with a density of 52 veh/mi/In, and the jam density is 125 veh/mi/In, determine the following: (i) The length of the queue at the end of the red phase (ii) The maximum queue length (iii) The time it takes for the queue to dissipate after the end of the red indication.
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TRANSPORTATION ENGINNERING-TRAFFIC SIGNALS An approach to a predetermined signal has 25 seconds of effective green for a 60 second cycle. The approach volume is 500 vehicles/hour and the saturation flow rate is 1400 vehicles/hour. Calculate the average vehicle delay using D/D/1 queing.
PROBLEM 1. Consider a signalized intersection approach in which the arrival rates are different during the effective green and red times during a given phase. During the effective green, there is only one lane group with an arrival rate of 2,400 vehicles per hour and 2700 vehicles per hour during the rest of the cycle (during the effective red). The cycle length is of 90 seconds, the effective green is 30 seconds and the saturation rate is 8,000 veh/h. Questions: a) Estimate the average uniform delay for this approach b) Consider that this approach has an upgrade of 4%. The total width of the cross street at this intersection is 60 feet. The average vehicle length of approaching traffic is 16 feet. The speed of approaching traffic is 40 mi/h. Determine the sum of the minimum necessary change and clearance intervals.
Problem Exercise Traffic flow on a road is 1800veh/hr/lane and density of 14.4 veh/km/lane. To reduce speeding on a section of highway, a police cruiser decides to implement a rolling roadblock, and to travel in the left lane at the speed limit of 88 kph for 10 km. No one dares to pass. After the police cruiser joins the traffic flow, the platoon density increases to 20veh/km/lane and traffic flow drops. • How many vehicles (per lane) will be in the platoon when the police car leaves the highway? WBA 'A. B,