An incident occurs on a freeway that has a capacity in the northbound direction, before the incident, of 4000 veh/h and a constant flow of 2900 veh/h during the morning commute (no adjustments to traffic flow result from the incident). At 8:00 A.M. a traffic accident closes the freeway to all traffic. At 8:12 A.M. the freeway is partially opened with a capacity of 2000 veh/h. Finally, the wreckage is removed, and the freeway is restored to full capacity (4000 veh/h) at 8:31 A.M.

An incident occurs on a freeway that has a capacity in the northbound direction, before the incident, of 4000 veh/h and a constant flow of 2900 veh/h during the morning commute (no adjustments to traffic flow result from the incident). At 8:00 A.M. a traffic accident closes the freeway to all traffic. At 8:12 A.M. the freeway is partially opened with a capacity of 2000 veh/h. Finally, the wreckage is removed, and the freeway is restored to full capacity (4000 veh/h) at 8:31 A.M.

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 25P

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An incident occurs on a freeway that has a capacity in the north bound direction, before incident, of 4000 veh/h and a constant flow of 2900 veh/h during the morning commute (no adjustments to traffic flow result from the incident). At 8:00am, a vehicle crash closes the freeway to all traffic. At 8:12am, the freeway is partially opened with a capacity of 2000 veh/h. Finally, the crash site is removed and the freeway is restored to full capacity of 4000 veh/h at 8:31am. Assuming the traffic follows a D/D/1 queueing (FIFO queue discipline) to determine time of queue dissipation, longest queue length, total delay, average delay per vehicle, and longest wait of any vehicle.
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A stream of traffic moving at a speed of 40km/h and a concentration of 20veh/km is stopped for 2mins by a herd of cattle crossing the road. After the herds departure, the vehicles began moving at a speed of 20km/h and a concentration of 60veh/km. Assuming a jam concentration of 150veh/km, calculatei. The velocity and direction of the stopping waveii. The length of the line of cars stopped during the 2mins periodiii. The number of cars stopped during the 2minsiv. The velocity of the shock wave resulting from the dissipation of the queue
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