Development and Evaluation of a Coordinated and Conditional Bus Priority Approach

One problem in existing bus priority strategies is that while a decision is being made to grant priority at an intersection, the bus arrival time at the downstream intersections is not considered. Moreover, only strategies for late buses are discussed; the strategies for early buses are seldom studied. This research tests a different bus priority approach, coordinated and conditional bus priority (CCBP). Coordinated, signalized intersection groups are adopted as control objects. Buses are detected one or more cycles before their arrival at the first intersection of the control object. A CCBP, with two kinds of priority strategies (increasing and decreasing bus delay strategies), is proposed. A model was built to generate the optimal combination of priority strategies for intersection groups so that the real delay of buses would be close to the permitted delay defined by the bus operation system. In the field application, the CCBP approach is compared with other two options: no priority and unconditional priority. Significant reductions on bus delay deviation and bus headway deviation were achieved with the use of the CCBP approach. Application of the CCBP approach resulted in only minor increases in total average delay of motor vehicles. The results of the field application studies performed as part of this study suggested that the CCBP approach could be used to decrease bus delay deviation and enhance the reliability of bus service without significantly affecting the delay of other motor vehicles.