Summary: "Gray market" vehicles are cars and trucks imported into the United States, either permanently or temporarily, by persons other than the original manufacturer; permanent imports must be converted to meet U.S. safety standards. The National Highway Traffic Safety Administration (NHTSA), which runs the gray market program, has yet to set user fees to cover program costs, and registered importers have not recalled gray market vehicles when manufacturers have recalled similar vehicles. More significantly, NHTSA still has few assurances that gray market vehicles that the Customs Department has identified as temporary imports ultimately either leave the United States or are converted to meet U.S. standards. Despite these limitations, safety considerations warrant extending and strengthening the gray market program. Although relatively few gray market vehicles are now being imported--fewer than 300 in 1992--this figure probably understates the actual number of such imports. Further, future changes in the exchange rates and other financial incentives could make importing gray market vehicles more attractive. GAO recommends that the Transportation Department (1) evaluate the merits of a uniform vehicle identification number code to indicate whether vehicles were originally built to conform to U.S. safety standards and (2) improve cooperation among state and federal agencies to better identify and control gray market vehicles.