The Foundation of America’s Modern Interstate System: A Legacy Launched with the Federal Highway Act of 1921
The foundation for America’s modern interstate highway system was laid with the passage of the Federal Highway Act of 1921. This landmark legislation authorized the Bureau of Public Roads to collaborate with state highway departments, initiating the systematic funding and development of paved, two-lane roads across the United States. More than just a transportation initiative, it was a strategic move to unify a growing nation—linking rural regions with urban centers, facilitating commerce, and reinforcing the economic and political bonds between states.
Throughout the 1920s and 1930s, this federally supported effort expanded steadily, marked by a series of critical legislative advancements. Among these was the Miller Act of 1935, which established vital performance and payment protections for contractors engaged in federally funded public works. This act played a significant role in shaping equitable contracting standards that still influence infrastructure delivery models today. However, despite this forward momentum, the construction of the national highway system came to a near standstill in 1941, as the United States shifted its industrial and logistical priorities toward the global demands of World War II. Resources, labor, and federal funding were reallocated to support wartime mobilization, delaying the full realization of a unified interstate network until the postwar era.
Following the end of World War II, the United States saw a gradual return to normalcy, and efforts to expand the Interstate Highway System resumed. By the late 1940s, construction was once again progressing. However, in November 1950, that momentum was disrupted as the Korean War intensified. With national attention shifting toward military engagement, funding and materials originally allocated for highway development were redirected to support defense needs. As a result, the interstate program was once again paused, with infrastructure taking a back seat to wartime priorities.
It wasn’t until 1953, under the leadership of President Dwight D. Eisenhower, that the vision for a unified national roadway system began to materialize. With the implementation of what would become known as the Dwight D. Eisenhower National System of Interstate and Defense Highways, the Interstate Highway System finally took definitive form—laying the groundwork for the expansive, integrated network of roads we rely on today.
Although much of the construction was financed by the federal government, Interstate Highways are owned and maintained by the individual states in which they are located. As a condition of federal funding, these highways are required to meet uniform national standards—including compliance with federal traffic control specifications, controlled access design, and the elimination of at-grade intersections, among other criteria—ensuring consistency, safety, and efficiency across the national network.
