Metropolitan planning organization in the context of "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 the United States Numbered Highway System, as well as other roads serving major airports, ports, military bases, 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 (USDOT) in cooperation with the states, local officials, and metropolitan planning organizations (MPOs) and approved by the United States Congress in 1995.