Question

A traffic signal has a 60-second cycle length. For the travel direction of interest, the effective red and green times are 30 seconds each, the arrival rate is constant at 20 vehs/min and the saturation flow (i.e., the queue discharge rate) is 1 veh/sec.

a. Calculate the average delay (in seconds) for the travel direction of interest

b. What is the maximum length of a queue (in vehicles)?

c. Assume that works on the street are taking place downstream of the intersection so that only 20 vehs/min (in the direction of interest) can pass. Calculate the average delay [sec] caused by the street work to a vehicle leaving the intersection. Assume that the queue at the downstream restriction never backs-up into the intersection.

Answer 1

ANSWER:---

AVERAGE DELAY:-- The average total delay per vehicle is computed only for the vehicles completing the travel-time measurement section. The delay is computed for each vehicle by subtracting the ideal travel time from the actual travel time.

MAXIMUM LENGTH OF QUEUE:---- The Maximum Queue (feet) is the maximum observed distance from the stop bar to the back of queue over the analysis period. Note that Maximum Queue is limited by the length of the link.