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National Defense and Interstate Highway Act of 1956

Last Updated: 2006

The Federal-Aid Highway Act of 1956 established the Dwight D. Eisenhower System of Interstate and Defense Highways. No government project stimulates the nation’s economy and positions the United States to remain the world’s preeminent power in the twenty-first century as does its first-class system of interstate highways. The freedom to drive from one coast to the other, from the Gulf of Mexico to Canada—without red lights and railroad crossings—gives credibility to democratic capitalism.

The United States leads the world in superhighway mileage. Virtually all major urban areas are connected by interstate highways. The longest interstate route is I-90 from Seattle to Boston—3,020.54 miles.

Under the act, Congress combined existing highways into the interstate highway system, which is administered by the secretary of commerce. Initially, Congress authorized $31.5 billion over thirteen years to finance up to 90 percent of the project’s costs. At $8.0 billion, I-95 from Miami to Maine is the most expensive route.

The 1956 Act guaranteed construction of all segments on a “pay-as-you-go” basis. Eisenhower insisted that the program be self-financing without contributing to the federal budget. User fees came from taxes on gasoline, tires, and truck manufacturers. These fees funded a permanent Highway Trust Fund that continues to finance highway projects.

The sheer size and scale of the construction program caused controversy. Interstate impacts on our cities remain divisive. The dominance of the automobile was established. The decentralized, automobile-dependent metropolis is a reality.

The interstate highway system has adopted uniform standards for highway construction throughout the nation. Access to all interstates is fully controlled. No intersections or traffic signals hamper travelers. All traffic and railroad crossings are separate. More than 55,000 bridges support the system.

Interstates consist of two lanes in each direction—or at least four traffic lanes. Curves are engineered for safe negotiation at high speed. Grades are moderated. Routes with odd numbers run north and south. Even numbered roadways run east and west. The defensive character of the system is captured in the interstate’s route marker, which is a red, white, and blue shield—carrying the word “Interstate,” the state name, and the route number.

The interstate highway system is the “workhorse” of the nation’s highway system. While it comprises just over 1 percent of the nation’s highway system mileage, it carries 23 percent of all roadway traffic.

The interstate highway system has a profound effect upon the American economy—contributing significantly to improved economic efficiency and productivity. Freight costs are reduced substantially. Development is encouraged as less expensive land is made more accessible to the nation’s transportation system. Employment freedom is expanded. Rural residents use interstate highways to reach employment centers. The American dream of the single-family house in the suburbs is realized.

The interstate highway system creates a genuinely national domestic market. Companies supply their products to much larger geographical areas with less expense. Labor and capital are more efficient. New highway structures encourage business expansion, new investments, and job creation.

The impacts on quality of life are noteworthy. Higher speeds make time savings possible. No nation matches the mobility available to the overwhelming majority of citizens. American interstate highways blend partisan, policy, and system politics. The result is a systemic force for expanding political economy.

SEE ALSO: Transportation Policy