Analysis of performance of transitional preemption strategy for traffic signal near at-grade railway grade crossing

Because the prime objective of current preemption methods at signalized intersections near highway-railroad grade crossings is to clear the crossing, secondary objectives such as safe pedestrian crossing and vehicle delay are given less consideration or are ignored completely during the preemption. Under certain circumstances state-of-the-practice traffic signal preemption strategies may cause serious pedestrian safety and efficiency problems at signalized intersections near highway-railroad grade crossings. Recently, an Improved Transition Preemption Strategy (ITPS) that is specifically designed to improve intersection performance and pedestrian safety was developed by Cho and Rilett. Even if the ITPS algorithm improved both the safety and efficiency of signalized intersections near highway-railroad grade crossings, it is impossible to measure the exact benefit of ITPS because the ITPS algorithm was tested only for the worst case scenario at the development stage. For this paper, the ITPS algorithm was tested under normal operating condition, that is, trains were designed to arrive at the crossing randomly during the cycle. Also, the effect of pedestrians was analyzed using a VISSIM simulation model which was calibrated to field conditions. Finally, a benefit/cost analysis was performed. It was concluded that the ITPS algorithm improves both the safety and efficiency of signalized intersections near highway-railroad grade crossings for normal operating condition.