A Global Optimization Approach to Solve the Traffic Signal Synchronization Problem

Abstract

The Traffic Signal Synchronization is a traffic engineering technique of matching the green light times for a series of intersections to enable the maximum number of vehicles to pass through, thereby reducing stops and delays experienced by motorists. Synchronizing traffic signals ensures a better flow of traffic and minimizes gas consumption and pollutant emissions. The objective function used in this work is a weighted sum of the delays caused by the signalized intersections. In this paper, we apply generalized’surrogate problem’ methodology that is based on an on-line control scheme which transforms the problem into a’surrogate’ continuous optimization problem and proceeds to solve the latter using standard gradient-based approaches while simultaneously updating both actual and surrogate system states. We extend a ‘surrogate problem’ approach that is developed for a class of stochastic discrete optimization problems so as to tackle the traffic signal synchronization problem to minimize the total delay (DTSS). Numerical experiments conducted on a test and a real networks show that the surrogate method converges in a very small area.