Fundamental Insight into Signal Plan Transition Methods

This paper describes, in detail, the concrete operational mechanisms of the Corridor Simulation (CORSIM)–embedded signal transition algorithms. Through detailed analysis of these transition algorithms, this study found that controller configurations, such as minimum green time for main street and recall mode, are important factors affecting plan transition performance. Specifically, this study demonstrated that even when the same transition method is used, the operational result can vary significantly according to these controller configurations. A simulation study was performed to comparatively evaluate delay performance of plan transition algorithms under two operational situations, namely, transition into peak and out of peak traffic demands. Although the shortway method showed the best performance for most simulation scenarios, the three-cycle and immediate methods could be included in the best-performing group in the case of transition into peak through an adjustment of the main street minimum green time. By contrast, these pretimed transition algorithms experienced markedly higher side-street delay during the transition out of peak demand because of the relatively long main street green time required by these transition methods.