Modeling the traffic signal control system at an isolated intersection using queuing systems

As the population grows in cities worldwide, the number of vehicles present on the roadways also increases, resulting in slow-moving and congested traffic. Therefore, a widespread problem in large cities concerns the traffic in the streets. Traffic signals are one of the most powerful tools available to city authorities for urban traffic control. Their proper installation can improve both traffic flow and the safety of all road users. Extensive research has been conducted to reduce the impacts of long car queues, based mainly on traffic signal timing optimization. This paper estimates the average waiting time at an isolated intersection and optimizes the timing of the green and red phases using an analysis of queueing systems. The control system is assumed to be the fixed-time type, and the Poisson process is considered for the arrivals. The proposed model is applied to real traffic data at a two-phase intersection in Bojnurd, Iran. It needs to be noted that the current situation at the intersection under study reduces average waiting time only for one side, but the analytic model can reduce average waiting time for the whole intersection. Moreover, simulation experiments are carried out, the results of which verify the capabilities of the proposed methodology in traffic signal control applications.