3 - Security

Ensuring the security of all transportation systems and the people who use them is a national priority. While much of the initial national focus after the September 11, 2001, terrorist attacks was on aircraft and airports, today attention is also directed at other modes, including rail, water, highways, and pipelines. Another national security issue is U.S. dependency on foreign sources of oil. The U.S. transportation sector remains almost entirely dependent on petroleum as an energy source, and nearly two-thirds of the petroleum used in the United States is imported.