National Highway System (United States)

The National Highway System (NHS) is a network of strategic highways within the United States, including the Interstate Highway System and other roads serving major airports, ports, rail or truck terminals, railway stations, pipeline terminals and other strategic transport facilities. Altogether, it constitutes the largest highway system in the world.

Individual states are encouraged to focus federal funds on improving the efficiency and safety of this network. The roads within the system were identified by the United States Department of Transportation in cooperation with the states, local officials, and metropolitan planning organizations and approved by the United States Congress in 1995.

National Highway System
National Highway System
System map with Interstate Highways in blue and other components in red
System information
Length160,955 mi (259,032 km)
FormedNovember 28, 1995
Highway names
InterstatesInterstate nn (I-nn)
US HighwaysU.S. Highway nn, U.S. Route nn (US nn, US-nn)
StateVaries by state
County roadsCounty Road nn, County Route nn (CR nn, Co. Rd. nn)
Other local roadsVaries by locality
System links
  • National Highway System


The Intermodal Surface Transportation Efficiency Act of 1991 provided that certain key routes such as the Interstate Highway System, be included.[1]

The National Highway System Designation Act of 1995 (Pub.L. 104–59, 109 Stat. 568) is a United States Act of Congress that was signed into law by President Bill Clinton on November 28, 1995. The legislation designated about 160,955 miles (259,032 km) of roads, including the Interstate Highway System, as the NHS.

Aside from designating the system, the act served several other purposes, including restoring $5.4 billion in funding to state highway departments, giving Congress the power to prioritize highway system projects, repealing all federal speed limit controls, and prohibits the federal government from requiring states to use federal-aid highway funds to convert existing signs or purchase new signs with metric units.[2]

The act also created a State Infrastructure Bank pilot program. Ten states were chosen in 1996 for this new method of road financing. These banks would lend money like regular banks, with funding coming from the federal government or the private sector, and they would be repaid through such means as highway tolls or taxes. In 1997, 28 more states asked to be part of the program. Ohio was the first state to use a state infrastructure bank to start building a road. An advantage to this method was completing projects faster; state laws and the lack of appropriate projects were potential problems.[3]


Strategic Highway Network
A map of the Strategic Highway Network, one component of the NHS.
FHWA 2015 flow map freight
Map of average freight truck traffic on the NHS, 2015

According to the Federal Highway Administration, the 160,000-mile (260,000 km) National Highway System includes roads important to the United States' economy, defense, and mobility, from one or more of the following road networks (specific routes may be part of more than one sub-system):[4]

  • Interstate Highway System: The entire Interstate Highway System (which is also known as the Dwight D. Eisenhower National System of Interstate and Defense Highways) is included in the NHS, but retains its separate identity within the NHS.
  • Other Principal Arterials: Highways in rural and urban areas which provide access between an arterial and a major port, airport, public transportation facility, or other intermodal transportation facility. (Facilities accessed include 207 airports, 198 ports, 190 rail or truck terminals, 67 Amtrak railway stations, 58 pipeline terminals as well as 82 intercity bus terminals, 307 public transit stations, 37 ferry terminals, and 20 multi-purpose passenger terminals.)[5]
  • Strategic Highway Network (STRAHNET): The entire network of highways which are important to the United States’ strategic defense policy and which provide defense access, continuity, and emergency capabilities for defense purposes.[6]
  • Major Strategic Highway Network Connectors: Highways which provide access between major military installations and routes which are part of STRAHNET.
  • Intermodal Conectors: Routes which provide access between major intermodal facilities and the other four subsystems making up the NHS.[7]

The system includes 4% of the nation's roads, but carries more than 40% of all highway traffic, 75% of heavy truck traffic, and 90% of tourist traffic.[5] All urban areas with a population of over 50,000 and about 90% of America's population live within 5 miles (8.0 km) of the network,[5] which is the longest in the world.[8]

See also

  • Blank shield.svg U.S. Roads portal


  1. ^ National Transportation Library. "Intermodal Surface Transportation Efficiency Act of 1991". National Transportation Library. Retrieved April 2, 2013.
  2. ^ Federal Highway Administration. "Interstate FAQ: Why don't you put metric speed and distance signs on the Interstate System?". Celebrating the Eisenhower Interstate Highway System. Federal Highway Administration. Retrieved August 23, 2008.
  3. ^ Schienberg, Phyllis (March 6, 1997). "Statement of Phyllis Schienberg, Prospects for Innovation Through Research, Intelligent Transportation Systems, State Infrastructure Banks, and Design-Build Contracting". US Senate Committee on Environment and Public Works. Retrieved July 9, 2012.
  4. ^ Natzke, Stefan; Neathery, Mike & Adderly, Kevin (September 29, 2017). "What is the National Highway System?". National Highway System. Federal Highway Administration. Retrieved January 29, 2019.
  5. ^ a b c Slater, Rodney E. (Spring 1996). "The National Highway System: A Commitment to America's Future". Public Roads. Washington, DC: Federal Highway Administration. 59 (4). ISSN 0033-3735. Retrieved July 9, 2012.
  6. ^ Federal Highway Administration (November 7, 2014). "Chapter 18: Strategic Highway Network (STRAHNET)". Status of the Nation's Highways, Bridges, and Transit: 2004 Conditions and Performance. Federal Highway Administration. Retrieved August 27, 2015.
  7. ^ Natzke, Stefan; Neathery, Mike & Adderly, Kevin (April 6, 2018). "Intermodal Connectors". National Highway System. Federal Highway Administration. Retrieved January 29, 2019.
  8. ^ Cox, Wendell (January 22, 2011). "China Expressway System to Exceed US Interstates". New Geography. Retrieved July 9, 2012.

 This article incorporates public domain material from websites or documents of the United States Department of Transportation.

External links

American Highway Users Alliance

The American Highway Users Alliance (informally Highway Users, previously Highway Users Federation, National Highway Users Conference), is a non-profit advocacy group representing many businesses in the automotive and road construction sector. The organization, which was founded by General Motors and others in 1932, merged with the Automotive Safety Foundation and Auto Industries Highway Safety Committee in 1970.

It lobbies for sustained investment in the highway system and claims to have been "instrumental in the passage of virtually all major highway and traffic safety legislation over the past 75 years". It argues that revenue from federal US fuel taxes should be used to fund major highway projects and programs. It publishes research proposals relating to specific highway improvement proposals and regular reports that highlight the most congested roadway bottlenecks in the country.

The organization advocates that strategic development of the highway system would reduce congestion, reduce greenhouse gas emissions and improve Road Traffic Safety.

National Highway

National highway or National Highway may refer to:

National Highway (Australia)

List of National Roads in Belgium

Brunei National Roads System

National Highway System (Canada)

Trans-Canada Highway

China National Highways

Danish national road network

Route nationale


National Highway (India)

National primary road

National secondary road

State highway (Italy)

National highways of Japan

List of National Roads in Latvia

Malaysian Federal Roads System

Mexican Federal Highway

New Zealand state highway network

Norwegian National Road

National Highways of Pakistan

National roads in Poland

Russian federal highways

National routes (South Africa)

National highways of South Korea

List of national roads in Spain

Swedish national road

Turkish State Highway System

State Highways (Ukraine)

National Routes of Uruguay

United States Department of Transportation

The United States Department of Transportation (USDOT or DOT) is a federal Cabinet department of the U.S. government concerned with transportation. It was established by an act of Congress on October 15, 1966, and began operation on April 1, 1967. It is governed by the United States Secretary of Transportation.

United States Numbered Highway System

The United States Numbered Highway System (often called U.S. Routes or U.S. Highways) is an integrated network of roads and highways numbered within a nationwide grid in the contiguous United States. As the designation and numbering of these highways were coordinated among the states, they are sometimes called Federal Highways, but the roadways were built and have always been maintained by state or local governments since their initial designation in 1926.

The route numbers and locations are coordinated by the American Association of State Highway and Transportation Officials (AASHTO). The only federal involvement in AASHTO is a nonvoting seat for the United States Department of Transportation. Generally, north-to-south highways are odd-numbered, with lowest numbers in the east, and highest in the west. Similarly, east-to-west highways are typically even-numbered, with the lowest numbers in the north, and highest in the south. Major north–south routes have numbers ending in "1" while major east–west routes have numbers ending in "0". Three-digit numbered highways are generally spur routes of parent highways (thus U.S. Route 264 is a spur off of U.S. Route 64). Some divided routes (such as U.S. Route 19E and U.S. Route 19W) exist to provide two alignments for one route. Special routes, which can be labeled as alternate, bypass or business, depending on the intended use, provide a parallel routing to the mainline U.S. Highway.

Before the U.S. Routes were designated, auto trails designated by auto trail associations were the main means of marking roads through the United States. In 1925, the Joint Board on Interstate Highways, recommended by the American Association of State Highway Officials (AASHO), worked to form a national numbering system to rationalize the roads. After several meetings, a final report was approved by the U.S. Department of Agriculture in November 1925. They received complaints from across the country about the assignment of routes, so the Board made several modifications; the U.S. Highway System was approved in November 1926. As a result of compromises made to get the U.S. Highway System approved, many routes were divided, with alignments to serve different towns. In subsequent years, AASHTO called for such splits in U.S. Routes to be eliminated.

Expansion of the system continued until 1956, when the Interstate Highway System was formed. After construction was completed, many U.S. Routes were replaced by Interstate Highways for through traffic. Despite the Interstate system, U.S. Highways still form many important regional connections, and new routes are still being added.

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