NOTES: Transit includes motor bus, heavy rail, commuter rail, light rail, ferryboat, trolley bus, demand responsive, and others. Motor bus and demand responsive figures are also included in the bus figure for highway.
SOURCES: Passenger-miles—U.S. Department of Transportation, Bureau of Transportation Statistics, National Transportation Statistics 2002 (Washington, DC: 2002), table 1-34, also available at http://www.bts.gov/, as of April 2003.
Gross Domestic Product—Based on chained 1996 dollar data from U.S. Department of Commerce (USDOC), Bureau of Economic Analysis, National Income and Product Accounts, summary GDP table, available at http://www.bea.doc.gov/bea/, as of May 2003. Population—USDOC, U.S. Census Bureau, National Intercensal Estimates 1990-2000, available at http://census.gov/popest/data/national/tables/intercensal/US-EST90INT-01.php, as of May 2003.