Collisions at highway-railroad grade crossings have posed a significant safety problem. To reduce the number of these collisions at highway-railroad grade crossings where train visibility is a contributing factor, the Federal Railroad Administration (FRA) is investigating measures to enhance the visibility of trains with the use of retroreflectors on freight cars. A four-phase research program was conducted to determine the feasibility of reflectorization as a train conspicuity device. A literature review provided past and current transportation experiences on the use of retroreflectors. A demonstration test was conducted to establish the durability of a newly developed (microprismatic) material, and to create a retroreflective pattern to test for the next phase of research. A nationwide in-service test was conducted to measure the microprismatic retroreflectors' performance, accident reduction potential, and costs. A human factors test was conducted to evaluate the detectability and recognition of several retroreflective designs. Results from this research indicate that a uniform, recognizable pattern of reflectorized material can facilitate recognition of a freight car. The durability of the microprismatic material tested indicates that adequate intensity levels can be sustained up to 10 years with maintenance.