High profile highway-rail grade crossings present a severe risk to low ground clearance vehicles such as low-boys, car-carriers, low-floor urban transit buses, and farm equipment trailers in the United States. When such a vehicle traverses a high-profile roadway section, such as a high-profile grade crossing, the vehicle may become stuck on the hump of the crossing and then be struck by a train. One such incident involved a tractor trailer that became stuck at a grade crossing in Glendale, CA on January 28, 2000 and was subsequently struck by a Metrolink commuter train. This problem could be more complicated considering that fact that the underbody of a commercial vehicle is not always a flat surface. There could be electric cables, air lines, tanks, storage cabinets, etc. suspended from the flat surface of the underbody of a commercial vehicle. It is aimed to have a detecting approach that will be able to take these suspended or protruded accessories into account and sense whether these suspended or protruded vehicle parts or accessories are rigid, semi-rigid, or flexible. Would they be rigid enough to get the commercial vehicle stuck on the high-profile grade crossing? One of the ways to reduce the risk to low ground clearance vehicles is to provide advance warning regarding the existence of high-profile crossings ahead. Passive signage already exists for this application (w10-5). However, research is needed into the development of a reliable active system, such as the ones used to detect over-height vehicles before tunnels, that would detect a low ground clearance vehicle on approach to a high-profile crossing and trigger a wayside active warning message that would be visible to the motorist. The system envisioned would be capable of generating its own power, be durable enough for long-term operation with minimal maintenance, and able to operate in adverse conditions including heavy snow. Ultimately it would achieve at least the same level of reliability and quality assurance as existing over-height vehicle detection systems. Recommendation should also be made as how far the developed detection system should be placed away from the grade crossing to allow low-ground clearance vehicle sufficient space to stop ahead of the crossing. The allowable stopping distance, of course, depends on the speed limit for the roadway plus some safety factor. The ideal placement should allow a low-ground clearance vehicle to take an alternative route or detour before reaching the high-profile grade crossing. Some engineering research and analysis are also necessary to recommend an accurate and scientific-based approach for calculating the actual clearance threshold that should consider the specific nature of each individual high-profile grade crossing and the dynamic behavior of the vehicle at the crossing. Expected Phase I Outcomes: Outcomes expected from the Phase I include a detailed concept that demonstrates the viability of creating a prototype that satisfies the attributes described above. It should also estimate the cost of the proposed technology (with and without installation) per grade crossing. Offer should indicate to what degree the offeror has successfully commercialized products of past projects. Expected Phase II Outcomes: Phase II efforts include manufacturing and demonstrating a working prototype low ground clearance vehicle detection system that demonstrates potential for achieving reliability and quality assurance metrics equivalent to or greater than existing over-height vehicle detection systems.