Computational Algorithm for a Fixed Cycle Traffic Signal and New Approximate Expressions for Average Delay

A computational algorithm for several characteristics such as the average delay, the average queue length and the probability of clearing the queue is devised for a fixed cycle traffic signal. The values of the average delay given by several theoretical expressions are compared with the exact values computed by the present algorithm. This comparison suggests new approximate expressions for the average delay. New approximate expressions and existing approximate expressions including Webster's full expression and Newell's expression are compared numerically with exact values of the average delay. It is shown that new approximate expressions give almost exact values of the average delay. In addition it is shown that Newell's expression is the most accurate of the existing approximate expressions.