Improved Pedestrian Sight-Distance Needs at Railroad-Highway Grade Crossings

This paper presents an improved model for pedestrian crossing time that is used to establish preliminary guidelines for lateral clearance needs on railroad-highway grade crossings. The improved model includes new elements that are lacking in existing models such as pedestrian observation-reaction time, length of pedestrian unit, and safety margin. A general model for the required lateral clearance, that is applicable to any number of tracks on crossings located on horizontal curves or on tangent sections, was developed. The model can be used to determine the required lateral clearance to the right and to the left of the crossing, including maximum lateral clearance, its location, and lateral clearance at a specified location. A comparison of pedestrian crossing sight distance with intersection (vehicle) sight distance shows that lateral clearance needs for pedestrians are not generally satisfied by those currently available for vehicles. The presented design guidelines promote pedestrian safety and should be of interest to highway and railroad professionals. (C) 2017 American Society of Civil Engineers.