Modeling Signalized Intersections near Highway–Railroad Grade Crossings

Many roadway intersections throughout North America are located near highway–railroad grade crossings (IHRGCs). Numerous safety, operational, and legal challenges are associated with IHRGCs; and these become significantly more complex when traffic signals are present. Because of the complexity of traffic operations at IHRGCs, existing macroscopic analysis approaches are not suitable for in-depth analyses. Consequently, a more detailed methodology for the analysis of intersections with traffic signals located near IHRGCs was developed. The approach is microsimulation based and relies on hardware-in-the-loop architecture to model the traffic signal controller. To demonstrate the methodology, sensitivity analyses of key design parameters were undertaken, and their impacts on safety and delay were analyzed. Specifically, ( a) the maximum train speed and the corresponding length of the detector, ( b) the effect of the pedestrian volume, and ( c) the effect of the addition of an additional upstream train detector were examined in terms of safety and delay at the IHRGC. The methodology was tested with empirical data from a test bed in College Station, Texas. It was found that the manner in which the maximum train speed was calculated could have a statistically significant effect on delay and a detrimental effect on safety. It was also shown that the addition of an additional upstream detector could reduce delay and increase safety.