The U.S. Department of Transportation (DOT) John A. Volpe National Transportation Systems Center (Volpe), under the direction of DOT’s Federal Railroad Administration (FRA), Office of Research, Development and Technology, studied the use of unmanned aerial vehicles (UAVs) to produce accurate 3-dimensional models of high-profile highway-rail grade crossings. Volpe found that photogrammetry with ground control points can produce models with similar accuracy to those produce using LiDAR at a much lower cost. Volpe determined the process needed to achieve a simple measurement of ground clearance for these crossings and makes recommendations to FRA for pursuing this capability, and to work with FHWA to provide better information to drivers of low-clearance vehicles.