Under direction of the Federal Railroad Administration's Office of research and Development, the U.S. Department of Transportation's Research and Innovative Technology Administration's John A. Volpe National Transportation Systems Center conducted a technology assessment of low-cost active waning devices for application at passive highway-rail grade crossings. The objective of this research was to present an objective assessment of the available low-cost warning device technologies and recommend a migration path that would be facilitate implementation in the U.S.