Fundamentals of Transportation/Traffic Signals/Solution

An approach at a pretimed signalized intersection has an arrival rate of 500 veh/hr and a saturation flow rate of 3000 veh/hr. 30 seconds of effective green are given in a 100-second cycle. Analyze the intersection assuming D/D/1 queueing by describing the proportion of the cycle with a queue, the maximum number of vehicles in the queue, the total and average delay, and the maximum delay. 40px|left|ExampleSolution: With the statements in the problem, we know: Green Time = 30 seconds Red Time = 70 seconds Cycle Length = 100 seconds Arrival Rate = 500 veh/hr (0.138 veh/sec) Departure Rate = 3000 veh/hr (0.833 veh/sec) Traffic intensity, , is the first value to calculate. Time to queue clearance after the start of effective green: Proportion of the cycle with a queue: Proportion of vehicles stopped: Maximum number of vehicles in the queue: Total vehicle delay per cycle: Average delay per vehicle: Maximum delay of any vehicle: Thus, the solution can be determined: Proportion of the cycle with a queue = 0.84 Maximum number of vehicles in the queue = 9.66 Total Delay = 406 veh-sec Average Delay = 29.41 sec Maximum Delay = 70 sec /Solutions