The National Highway System is a network of nationally significant roads approved by Congress as required by the Intermodal Surface Transportation Efficiency Act (ISTEA) of 1991. It includes the Interstate system, the Strategic Highway Network (STRAHNET), and over 100,000 miles of arterial and other roads nationwide. Designation of the original system was completed on November 28, 1995, when President Clinton signed the National Highway System Designation Act of 1995 (Public Law 104-59). Intermodal Connectors were added to the system in 1998 when Congress approved the Transportation Equity Act for the 21st Century (TEA-21).
MAP-21 and Enhanced NHS
In 2012, Congress authorized a new transportation bill called Moving Ahead for Progress in the 21st Century (MAP-21). MAP-21 creates an Enhanced-NHS network by removing the limitation on the total number of NHS miles allowed and automatically adding any route that was functionally classified as a Principal Arterial as of October 1st, 2012 to the NHS network. For more information about MAP-21 and the NHS routes in Oregon, please see our webpage dedicated to the enhanced-NHS.
NHS Intermodal Connectors are NHS roads that provide service to major intermodal terminals. Section 101 of the National Highway System Designation Act of 1995 required the Secretary of Transportation to submit NHS Intermodal Connectors to Congress for approval. Congress approved the Intermodal Connectors in 1998 with the passage of the Transportation Equity Act for the 21st Century (TEA-21).