Transit Signal Progression Algorithm for Supporting Redwood Road Transit Signal Priority (TSP)

2020PDFTech ReportWang, QinzhengYang, Xianfeng TerryYuan, YunUniversity of Utah. Department of Civil and Environmental EngineeringUtah. Department of Transportation. Research and Innovation DivisionUnited States. Department of Transportation. Federal Highway AdministrationUtah. Department of TransportationUtahUnited StatesBefore and after studiesBus transitConnected vehiclesDedicated short range communicationsReliabilityRunning timeTraffic signal timingTravel timeWeb applicationsTraffic signal priorityTraffic ReliabilityBus Travel TimeBus Running TimeBus ProgressionBus TrajectoryUT-20.1619-8771Final Report Jan 2019 to Oct 2020In 2017, a connected vehicle (CV) corridor utilizing dedicated short-range communication (DSRC) technology was built along Redwood Road in Salt Lake County, Utah. The main purpose of the CV corridor was to implement transit signal priority (TSP) when a bus is running behind its published schedule. The performance data was generated by the transit vehicles. It was then transmitted through the DSRC system, logged by the traffic signal controller, and coupled with the Utah Transit Authority (UTA) data from the transit operation system. Then, it was analyzed including requested and served TSP, indicating bus reliability, travel time, and running time. To provide better signal coordination for buses, the signal plan for this CV corridor underwent retiming in October 2018. The goal of this project was to compare the TSP performance before and after the signal retiming. The field data of August, September, November, and December 2018 were selected for use in this evaluation. Although some negative impacts of TSP on street traffic are unavoidable in most cases, they can be minimized if the base signal control plan is properly designed. From an operational aspect, the best method for achieving this goal is to support bus progression along the corridor. Hence, another primary goal of this project was to develop a web-based tool to assist UDOT employees to design a signal progression plan to benefit both buses and passenger vehicles. This tool also helps to visualize bus running time, travel time, reliability, the bus served/requested ratio, and bus trajectory.122