Transportation law deals with public transportation on public highways and airspace, and is governed by both state and federal laws. Transportation laws can apply very broadly at the transport system level (such as laws pertaining to highways generally) or more narrowly to the transport of specific things (such as moving of highly flammable materials).
The United States Department of Transportation (DOT) sets a broad transportation policy for the country. The DOT was established by Congress in 1966 "to assure coordinated, effective administration of the transportation programs of the Federal Government." Under the DOT, there are 11 sub-agencies who are responsible for things such as highway planning, urban mass transit, railroad, aviation, and highways.
Some important federal laws which affect public transportation include: