National Interstate and Defense Highways Act of 1956

The National Interstate and Defense Highways Act of 1956 was a law passed in the United States to create a vast, modern highway system across the country. It authorized the construction of the Interstate Highway System—large, high-speed roads designed for efficient travel and transportation. Originally envisioned for military defense and emergency mobilization, the highways also transformed commerce, travel, and urban development. Funded mainly through federal and state cooperation, this act laid the foundation for America's extensive highway network, improving connectivity, safety, and economic growth nationwide.