Serious energy and environmental
issues are associated with transportation. The U.S . transportation sector
remains almost entirely dependent on petroleum as an energy source and more
than 50 percent of the petroleum used in the United States must now be imported.
Petroleum use is responsible for most of the environmental problems resulting
from transportation, including carbon dioxide emissions that may contribute
to global climate change.
Figure 6 U.S. Petroleum Production and Consumption: 1970-99 Million barrels per day
Source: U.S. Department of Energy, Energy Information Admin
istration, Annual Energy Review 1999 (Washington, DC: July 2000), Table 5.1.
