Integrating Bus Priority and Presignal Method at Signalized Intersection: Algorithm Development and Evaluation

Bus signal priority (BSP) is an effective strategy to enhance the quality of public transit service, but unfortunately, it also deteriorates the performance of general vehicles. However, the tandem intersection with midblock presignals can increase the intersection discharge capacity. The study aims to integrate BSP and presignal methods at the intersection to improve bus performance and relieve congestion. The phase scheme is designed, and signal states are classified into four categories. The control flow under each signal-state category is developed by considering the coordination between presignals and main signals. The algorithm is further compared with a tandem intersection without BSP and a traditional intersection with BSP based on simulations. The results show that (1) Integrating BSP and presignal at the intersection can provide huge benefits to buses. Compared with the average delay of general vehicles, the average delay of buses can be decreased by 70.7%. (2) Under medium and heavy traffic scenarios, the developed algorithm can decrease average intersection delay of general vehicles by 30.1%, thus, highlighting its potential to relieve traffic congestion.