Transportation, United States Department of, executive department of the U.S. government, established by the Department of Transportation Act of 1966. Its chief executive officer, the secretary, is a member of the president's cabinet. Its principal constituent organizations include the Federal Aviation Administration, the Federal Highway Administration, the Federal Railroad Administration, the National Highway Traffic Safety Administration, the Federal Transit Administration, the Maritime Administration, the Saint Lawrence Seaway Development Corporation, the Research and Special Programs Administration, and the Bureau of Transportation Statistics. The National Transportation Safety Board, established in 1966 as an entity within the department, was made totally independent in 1975.