Configuring Conventional Dual Signal Controllers for Transit Priority Using the Response Surface Methodology in Congested Urban Traffic Networks

Abstract This paper discusses the methodology of reconfiguring ordinary traffic signal controllers such as dual controllers to provide more functionalities beyond the conventional way of operation, in an optimal and a robust manner, aiming at transforming such controllers into smart standalone ATMS components. This paper presents an applied simulation-based response surface methodology (RSM) for the optimization of the reconfigured controllers. This RSM method was applied to a conventional actuated dual-traffic signal controller after modifying it to support additional functionalities of transit preemption. The modified controller was optimized using the RSM to perform best in congested and highly congested traffic networks. Two simultaneous objective functions were considered to maximize the transit throughput and minimize the network overall travel time. The results were analyzed for congested and highly congested traffic conditions, and the notion of robustness of the optimized dual controller was introduced, estimated and discussed. The performance of optimized controller was assessed comparatively against the traditional dual controller (not optimized), in a hypothetical simulation network origin-destination demand pairs and multiple overlapping transit routes, using 75 and 45 congested and highly congested traffic scenarios, respectively. The optimal controller outperformed the one without optimization in 65% and 96% of the congested and highly congested traffic cases, respectively.