Definitions for "Interstate Highway System"
The system of highways that connects the principal metropolitan areas, cities, and industrial centers of the United States. Also connects the United States to internationally significant routes in Canada and Mexico.
This system is part of the Federal Aid Primary system. It is a system of freeways connecting and serving the principal cities of the continental United States. (FHWA5)
created by Congress in 1956, the National System of Defense and Interstate Highways is a network of superhighways connecting all metropolitan areas within the United States . I-15 is part of that network.