It has been proven that Transit Signal Priority (TSP) strategies can reduce bus travel time as well as increase bus service reliability. Nonetheless, some major issues remain. The performance of TSP strategies may significantly increase traffic control delay if the TSP requests are frequent. Or TSP may further deteriorate the traffic conditions or even cause cycle failures at congested intersections. In this paper, the authors examined and estimated the potential performance of TSP under different scenarios composed of various signal control strategies and traffic demand levels. The authors also conducted a case study using the microscopic traffic simulation software, VISSIM, which contains a fully-functioned signal control emulator with a TSP module. The comparison between TSP and non-TSP strategies in simulation demonstrates that TSP strategies are not necessarily beneficial for all traffic scenarios. The comparison also explores the benefits of TSP with respect to the total traffic volumes, demand distributions and frequency of TSP requests at intersections. Lastly, the authors conducted a simulation study of a bus corridor of the City of Edmonton to identify intersections which can benefit from TSP. The simulation results show that TSP will reduce bus travel times as well as deteriorate the overall traffic performance. Disabling some of the TSP control may result in greater balance for the whole system.
