The 20th and 21st joint COTA International Conference of Transportation Professionals (CICTP 2020-21)

Safety and efficiency are two critical issues at highway-rail grade crossings (HRGCs) and their nearby intersections. The standard preemption, which is the current preemption method for traffic signals located near highway-rail grade crossings, is designed to clear vehicles off tracks as soon as possible. However, the underlying logic of current practice provides little or no consideration to 1) pedestrian safety, and 2) traffic signal efficiency of signalized intersections near highway-rail grade crossings (IHRGCs). As a result, the state-of-the-practice traffic signal preemption strategies may cause safety and efficiency problems at these intersections. On the other hand, standard traffic signal optimization programs are not designed to work on roadway networks that contain multiple HRGCs, because their underlying assumption is that the roadway traffic is in a steady state. However, for corridors that experience high train traffic (e.g. over 2 trains per hour) non-steady state conditions predominate. To solve these issues, this paper developed a simulation-based optimization methodology for estimating traffic signal timing plans on arterial corridors with multiple IHRGCs, and a case study was conducted to evaluate the methodology. A Genetic Algorithm (GA) was used as the optimization approach in the proposed methodology. A new transition preemption strategy for dual tracks (TPS_DT) and a train arrival prediction model were integrated in the proposed methodology. A study corridor with multiple HRGCs in Lincoln, NE was used in the case study, and a sensitivity analysis with different train traffic scenarios was conducted. Measurements of Effectiveness (MOEs) used for evaluation include rate of pedestrian cutoffs, intersection vehicle delay and corridor vehicle delay. It was concluded that the methodology can significantly improve both the safety and efficiency of traffic corridors with multiple IHRGCs.

CICTP