Decision Tree Model to Prioritize Signalized Intersections near Highway-Railroad Crossings for Railroad Interconnect

The Manual on Uniform Traffic Control Devices provides a list of factors to be considered when an agency is determining whether a highway railroad crossing located farther than 200 ft from a signalized intersection should have a railroad-preempted interconnection or be provided with alternative queue management methods. One such factor is the estimated queue length between the signalized intersection and the railroad crossing. Currently, no systematic assessment procedure both (a) quantitatively prioritizes intersections near railroad crossings on the basis of their potential to queue vehicles over the tracks and (b) is reasonably quick to apply agencywide. This paper proposes a decision tree procedure for screening and prioritizing traffic signals near highway railroad crossings on the basis of estimated queue lengths. An integral component of this procedure is the concept of queue margin, calculated as the difference between (a) clear storage distance between the track and the stop bar and (b) the estimated length of queue traffic. This prioritization procedure was applied to 595 traffic signals in northwest Indiana to prioritize and rank the top 20 intersections for more detailed site investigation. Example intersections are used to illustrate higher-fidelity data collection and queue management strategies.