Optimizing Minimum and Maximum Green Time Settings for Traffic Actuated Control at Isolated Intersections

Abstract

Optimization of signal control at isolated intersections has been an important research focus in traffic engineering over the past few years. Due to its flexibility and practicality, fully actuated control has been extensively deployed. In the conventional actuated control scheme, two important parameters, i.e., minimum and maximum green times, are arbitrarily prespecified, although it is widely recognized that they can significantly impact system operations. Previous studies have concentrated on computing these parameters using deterministic models. Due to the stochastic features of traffic arrival, such statically designated green time boundaries cannot sufficiently handle various traffic demands. To solve this problem, a stochastic model is established to dynamically optimize the minimum and maximum green times using real-time queue lengths and traffic arrival characteristics for each phase. Multiple criteria are fused and exploited as control objectives, such as avoiding cycle failures, minimizing control delays, and maximizing total traffic throughputs. Performance of the proposed algorithms is examined using a microscopic traffic simulation program, i.e., VISSIM 4.30, under various scenarios. The results show that the control system operated by the proposed algorithm produces promising improvements in system operation efficiency and fairness under various traffic demands.