Road-Junction Traffic Signal Timing Optimization by an adaptive Particle Swarm Algorithm

The purpose of this paper is to investigate the application of particle swarm optimization (PSO) algorithm in solving the traffic signal timing optimization problem. A local fuzzy-logic controller (FLC) installed at each junction is used to provide some initial solutions for the particle swarm optimization algorithm. Coordination parameters from adjacent junctions are taken into consideration by local fuzzy-logic controller. The membership functions and the rules of the fuzzy logic controller (FLC) are optimized using the standard particle swarm optimization (SPSO) algorithm. A new particle swarm optimization algorithm is used to optimize the average delay and average number of stops for adjacent junctions and to handle the constraints. The simulation results show that the delay per vehicle can be substantially reduced under constant traffic demands and time-varying traffic demands, particularly when the traffic demands on the upstream is larger than the traffic demand on the downstream. The implementation of this method does not require complicated hardware, and such simplicity makes it a useful tool for offline studies or real-time control purposes