Transit Signal Priority System Based On Intersection Reliability

Transit signal priority (TSP) can effectively improve the efficiency of the bus operation, but the traditional transit signal priority rarely considered the impact on intersection reliability and vehicles in the non-priority direction. However, TSP grant priority to the bus which may affect the efficiency of vehicles in the non-transit priority direction, especially when there is a severe congestion in the non-priority direction,which may cause failure of the intersection. Therefore, this paper mainly studies how to reduce the impact of TSP on vehicle in the non-priority direction while ensuring the intersection reliability and the efficiency of TSP,so that the traffic efficiency in the different direction is balanced.First of all, this paper builds a real-time transit signal priority system based on the connected vehicle technology, which address the problem that traditional transit signal priority technology cannot respond to the real-time traffic flow. Second, this paper studies how to apply the intersection reliability in the traffic signal optimization model,and establishes the bi-level transit signal priority model (BLTSP model) based on the intersection reliability. The objective of this optimization model is to minimize the influence of the transit signal priority on the vehicle in the non-priority direction while ensure the transit priority and intersection reliability. Finally, the case study of this paper proved the efficiency of the proposed model. When model applied in passive transit signal priority, results show that the BLTSP model is superior to the traditional model:the average vehicle delay in the non-priority direction compared with the traditional model decreased 22.54 s (17.63%), meanwhile, the vehicle delay increase slightly in the priority direction (2.87 s) and the passenger delay for entire intersection (0.26 s) have very small increase. In real-time transit signal priority case study, the result shows BLTSP model can save 20s travel time for bus compare to no TSP plan.