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Transportation Energy Use and Environmental Impacts
- Despite transportation’s continued dependence on petroleum, recent trends show decreasing import dependence, sharply reduced emissions of air pollutants, and small reductions in greenhouse gas emissions. U.S. dependence on imported oil decreased from a high of 60.3 percent in 2005 to 26.5 percent in 2014, largely as a result of increased domestic oil production.
- Transportation continues to rely almost entirely on petroleum to move people and goods. However, the sector’s dependence on petroleum decreased from a peak of 97.3 percent of transportation energy use in 1978 to 91.5 percent in 2014. This is due in part to increased blending of domestically produced ethanol in gasoline and improved fuel economy.
- The highway mode continues to dominate transportation energy use. Highway vehicles used 83.2 percent of total transportation energy in 2013, with personal vehicles accounting for 71.1 percent of highway energy use and 59.2 percent of total transportation energy use.
- Transportation is the second largest producer of greenhouse gas emissions (GHG), accounting for 27 percent of total U.S. emissions in 2013. Aside from greenhouse gases, the six most widespread or common air pollutant emissions from transportation fell below their 1990 levels and continued to decline from 2009 to 2014 due to many factors, including motor vehicle emissions controls that have contributed to considerable reductions.
- Across the 169 continuously monitored urban areas, the total number of very unhealthy air quality days that could trigger heath emergences warnings rose from 291 in 1990 to 361 in 2014.
- Significant pipeline oil spill incidents involved annual average spillage of about 69,000 barrels of oil (or 2,898,000 gallons) and other hazardous liquids each year for the three-year period 2012 through 2014. Between 2010 and 2013, derailments of oil tank cars released, on average, slightly less than 600,000 gallons per year.
- The energy required to move one person one mile or one ton of freight one mile has generally declined over time.
FIGURE 7a Transportation Energy Use by Energy Source: 1950–2014
KEY: Btu = British thermal unit
SOURCE: U.S. Department of Energy, Energy Information Administration, Monthly Energy Review, table 2.5. Available at http://www.eia.gov as of June 2015.
FIGURE 7b Energy Use by Mode of Transportation: 2013
KEY: Btu = British thermal unit
NOTES: The following conversion rates were used: Jet fuel = 135,000 Btu/gallon. Aviation gasoline = 120,200 Btu/gallon. Automotive gasoline = 125,000 Btu/gallon. Diesel motor fuel = 138,700 Btu/gallon. Compressed natural gas = 138,700 Btu/gallon. Distillate fuel = 138,700 Btu/gallon. Residual fuel = 149,700 Btu/gallon. Natural gas = 1,031 Btu/ft3. Electricity 1kWh = 3,412 Btu, negating electrical system losses. To include approximate electrical system losses, multiply this conversion factor by 3.
SOURCE: Air–Bureau of Transportation Statistics, Office of Airline Information. Rail–Association of American Railroads. Transit–Federal Transit Administration. Amtrak–National Railroad Passenger Corporation (Amtrak), personal communication with Energy Management Department and Government Affairs Department. Water– U.S. Department of Energy, Energy Information Administration and U.S. Department of Transportation, Federal Highway Administration. Pipeline– U.S. Department of Energy, Energy Information Administration. Highway– Federal Highway Administration as cited in U.S. Department of Transportation, Bureau of Transportation Statistics, National Transportation Statistics, table 4-6, available at www.bts.gov as of March 2015.