United States Fast Facts
Data are for 2011 unless otherwise noted.
Transportation System ExtentAll public roads: 4.08 million milesInterstate: 46,960 milesRoad bridges: 605,103Class I railroad trackage: 162,393 milesInland waterways: 29,620 milesPublic use airports: 5,172
Vehicles and ConveyancesAutomobiles...