U.S. Department of Energy - Energy Efficiency and Renewable Energy

Vehicle Technologies Office

Fact #320: May 17, 2004
The National Highway System

The National Highway System (NHS) Designation Act of 1995 (Public Law 104-59) was enacted to specify a network of nationally significant highways. It includes the interstate system and over 100,000 miles of arterial and other roads.

The NHS represents only about 4% of the nation's total public road miles and 6.6% of its lane miles, but carries over 44% of the travel. Most travel on the NHS takes place in urban areas even though there are more NHS miles in rural areas.

Map of the United States showing the national highway system.

Supporting Information

National Highway System, 2002
Public road miles 3,966,485
NHS miles 161,131
Share of NHS miles to public road miles 4.1%
Public lane miles 8,295,168
NHS lane miles 549,948
Share of NHS lane miles to public lane-miles 6.6%
All vehicle miles of travel 2,855,756
NHS vehicle miles of travel 1,269,372
Share of NHS vehicle miles of travel to All vehicle miles of travel 44.4%

Source: Federal Highway Administration (FHWA), Highway Statistics 2002, Tables HM-41, HM-20, HM-48, and VM-3.
Graphic from FHWA, Our Nation's Highways 1998.

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