Comparison of Alternate Signal Timing Policies

A signal timing policy describes operational goals applied when developing a timing plan for a system of coordinated intersections. This research investigates differences in signal timing plans resulting from implementation of five basic signal timing policies (including minimizing delay, minimizing stops, minimizing fuel consumption, maximizing coordination bandwidth, and a “baseline” policy). Further, this research investigates differences arising from application of different techniques to achieve the same policy goal (e.g., different techniques to maximize coordination bandwidth). Volume and other traffic signal data from four traffic signal systems are collected. Various computer tools including PASSER II-90 and TRANSYT-7F are used to develop signal timing plans that emphasize each policy. For the maximum bandwidth policies, several techniques for achieving the policy goal are applied. In all cases, the resulting signal timing plans are transferred to TRANSYT-7F for comparative simulation of detailed systemwide and route-specific measures of effectiveness. Review of these measures of effectiveness provides insights into the relative success of each timing policy, and the impacts of each policy on route-specific and overall system performance. Based on these insights, general guidelines for application of signal timing tools are proposed.