Sixty-four years ago, today…
Also known as the Federal Aid Highway Act of 1956 (Public Law 84-627), [it] was enacted on June 29, 1956, when President Dwight D. Eisenhower signed the bill into law. With an original authorization of $25 billion for the construction of 41,000 miles (66,000 km) of the Interstate Highway System, supposedly over a 10-year period, it was the largest public works project in American history [at] that time.
The addition of the term defense in the act’s title was for two reasons. First, some of the original cost was diverted from defense funds. Secondly, most U.S. Air Force bases have a direct link to the system. One of the stated purposes was to provide access in order to defend the United States during a conventional or nuclear war with the Soviet Union and its communist allies. All of these links were in the original plans, [though] some, such as Wright Patterson AFB, were not connected […] in the 1950s but, [were] later.
The money for the Interstate […] and Defense Highways was [drawn from] a Highway Trust Fund that paid for 90% of highway construction costs, with the states required to pay the remaining [10%]. It was expected that the money would be generated through new taxes on fuel, automobiles, trucks and tires. As a matter of practice, the federal portion of the cost of the Interstate Highway System has been paid for by taxes on gasoline and diesel fuel.
Eisenhower‘s support of the Federal Aid Highway Act of 1956 can be directly attributed to his experiences in 1919 as a participant in the U.S. Army’s first Transcontinental Motor Convoy across the United States on the historic Lincoln Highway, which was the first road across America. The convoy was memorable enough for a young Army officer, 28-year-old Lieutenant Colonel Dwight David Eisenhower, to include a chapter about the trip, titled Through Darkest America With Truck and Tank in his book At Ease: Stories I Tell to Friends (Doubleday and Company, Inc., 1967).
Following completion of the highways, the cross-country journey that took the convoy two months in 1919 was cut down to five days.
Additional Reading & Sources:
Federal Aid Highway Act of 1956: Creating The Interstate System (Federal Highway Administration)
Federal Highway Act of 1956 (Web Archive of the Class Brain Site)
Federal Aid Highway Act of 1956 (Wikipedia)