|Energy use (trillions of Btu)||5,654||5,606||5,898||6,220||6,326||6,315||6,706||6,959||7,272||7,048||7,046|
|Energy efficiency (ton-miles/thousand Btu)||0.506||0.512||0.516||0.511||0.510||0.512||0.490||0.483||0.469||0.491||0.495|
KEY: Btu = British thermal units.
NOTES: Ton-miles is a sum of individual ton-miles for air carriers, intercity trucks, Class I rail, and domestic water transportation. Energy consumption is the sum of usage by air carriers, single unit 2-axle 6-tire trucks, combination trucks, Class I rail (distillate/diesel fuel), and water transportation (residual and distillate/diesel fuel oil). Marine gasoline use data were excluded because marine gasoline is used primarily in recreational vehicles. Commercial domestic aviation fuel consumption data were estimated from total commercial domestic aviation fuel consumption. General aviation data were excluded because passenger and freight data cannot be disaggregated. Pipeline data were excluded because ton-miles data include all types of petroleum products and energy consumption data were available for natural gas only.
SOURCE: U.S. Department of Transportation (USDOT), Research and Innovative Technology Administration, Bureau of Transportation Statistics (BTS), calculations based on Ton-miles—see table 1-12b in appendix B. Energy use—USDOT, BTS, National Transportation Statistics 2004, tables 1-44, 4-6, and 4-8, available at http://www.bts.gov/, as of March 2005.