Signal design for an isolated intersection during congestion

This paper presents an algorithm for the signal design of an isolated intersection that will be able to alleviate long queues during severe congestion conditions, which cause both lengthy delays and harsh environmental damage. During such periods, the total effective green light is a scarce resource; its best allocation is crucial for the smooth operation of the intersection and sometimes even for a large network. The aim of the procedure presented here is to maximize the average throughput of the intersection. By achieving this goal, the number of vehicles in the queue is reduced at the fastest possible rate, and the period of congestion is shortened. The maximum throughput is achieved when the marginal flow in each phase is equal to the average throughput. The algorithm developed takes into account the decreasing flow rates of existing queues during long periods of green.