Improved transition preemption strategy for signalized intersections near at-grade railway grade crossing

Because the prime objective of the current preemption methods for traffic signals located near highway-railroad grade crossings is to clear vehicles from the crossing, secondary objectives such as maximizing pedestrian safety and minimizing vehicle delay are given less consideration and are often ignored completely. Consequently, the state-of-the-practice traffic signal preemption strategies may result in pedestrian safety and efficiency problems at signalized intersections near highway-railroad grade crossings (IHRGCs). The state-of-the-art transition preemption strategy (TPS) algorithm was designed to reduce the probability that pedestrians would be endangered when the standard preemption was initiated by approaching trains. However, there is a possibility of failure because the algorithm is predicated on the assumption that train arrivals can be predicted with certainty. Given the fact that current architecture may not be adequate with respect to safety and efficiency, there is a definite need for research on how to improve traffic signal preemption strategies. In this paper, an improved transition preemption strategy (ITPS) that is specifically designed to improve intersection performance while maintaining or improving the current level of safety is developed. It was concluded that the ITPS algorithm improves the operation of IHRGCs with respect to control delay while simultaneously reducing the probability of pedestrian conflicts associated with the standard preemption method and the TPS algorithm.