A Review on Bus Signal Priority Systems

Bus signal priority (BSP) is a traffic management measure which enhances the efficiency and service reliability of the buses. An efficient BSP helps in improving the bus travel time and reduces its delay at the signalized intersection while at the same time does not have an adverse impact on the overall network performance. This paper aims to provide a comprehensive review of the bus signal priority process by presenting the priority selection criteria, which discusses the different types of priority control strategy i.e. active priority and passive priority used and the criteria using which the priority is granted. It also gives an insight into the system architecture required for BSP implementation. The paper further discusses the model formulations for different priority control strategies focussing on the input data required, objective functions and constraints used in the formulation. Finally, the different methods used for BSP model evaluation in the literature along with the various performance indices used are presented.