"The Bureau of Transportation Statistics (BTS), a part of the U.S. Department of Transportation's (USDOT) Research and Innovative Technology Administration (RITA), presents 'State Transportation Statistics 2012', a statistical profile of transportation in the 50 states and the District of Columbia. This is the tenth annual edition of the 'State Transportation Statistics', and a companion document to the 'National Transportation Statistics (NTS)', which is updated quarterly on the BTS website. Like the previous editions, this document presents transportation information from RITA/BTS, other federal government agencies, and other national sources. A picture of the states' transportation infrastructure, freight movement and passenger travel, system safety, vehicles, transportation related economy and finance, energy usage and the environment is presented in tables covering the 50 states and the District of Columbia. Tables have been updated with the most recently available data."
United States. Department of Transportation: http://www.dot.gov/