Ring Barrier signal controller in VISSIM traffic simulation software provides different options for configuring Transit Signal Priority. This controller emulator allows for considering arterial progression by Priority Progression parameter; preferring specific transit signal priority calls to other calls by Priority Level feature; providing more green split to the signal priority phase by Green Extension attribute. This study aims to evaluate the impact of these three parameters on the performance of transit signal priority. The study area is based on three signalized intersections of Prices Fork Road in Blacksburg, Virginia. A total of five transit lines are assumed to request signal priority. Green Extension and Priority Level were found to have significant influence on bus delays, whereas bus frequency is not a significant variable to affect TSP effectiveness (for reducing the transit delays).

This study also aims to identify the traffic conditions in which the adaptive feature of VISSIM Ring Barrier Controller can be most useful. Detector Slack, Detector Adjust Threshold, and Adjust Step are the parameters that should be hardcoded in the controller for activating the adaptiveness feature. The study area (Prices Fork Road in town of Blacksburg, VA) incorporates five bus lines are assumed eligible to request priority. This study revealed that transit service overlap can enhance or exacerbate each bus performance when transit signal priority is implemented, depending on the scheduled headways and the frequency of signal priority requests in each intersection.