Federal-Aid Highway Act Signed, June 29, 1956

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Fifty-three years ago today, US President Dwight D. Eisenhower signed the Federal-Aid Highway Act of 1956. This act established what became known as The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly called the Interstate Highway System. The project remains the largest public works project in history. The entire system has a total length of nearly 47,000 miles, making it the largest highway system in the world.

Eisenhower's support of the Federal-Aid Highway Act of 1956 can be directly traced to 1919 and his experiences participating in the U.S. Army's first Transcontinental Motor Convoy across the United States. Following the historic Lincoln Highway, the first road built across the entire nation, the trip from Washington D.C. to San Francisco took two months to complete over the summer of 1919. Over the course of this journey, bridges cracked and had to be repaired, and vehicles were repeatedly stuck in mud.

Eisenhower’s observations and experiences on the Autobahn in Germany during World War II drove home the need for a national highway system in the United States. In his book 'At Ease: Stories I Tell to Friends', Eisenhower wrote, "The old convoy had started me thinking about good, two-lane highways, but Germany had made me see the wisdom of broader ribbons across the land."

Eisenhower’s support of the Highway Act was centrally based on his strong belief that the Interstate System was needed for the purpose of national defense. The military would need to have good roads for transporting equipment and troops in times of crisis. It was a valid point: the cross-country trip that took two months to complete in 1919 needed to be completed in a matter of days. Contrary to popular belief, no section of the Interstate Highway System was ever intended to be used as a runway by military aircraft, although many light planes have made emergency landings on interstates over the years.

Even though it is now difficult to imagine, Americans in the first five decades of the 20th century had to make due with a system of highways that barely deserved the name. At the turn of the century, the brand-new automobile quickly caught the fancy of the American public. In 1900, roughly 5,000 cars were produced. By 1917, approximately 3.5 million automobiles were registered in the United States. The new autos immediately pointed out the inadequacies of the current system of roads in America. First, roads had previously been designed for horses or iron-wheeled wagons. When the much heavier cars started whizzing along at twenty miles per hour on pneumatic tires, the old roads were quickly torn to shreds. Constant mud also took a toll on the cars' engines and undercarriages, which were not meant be used off of paved roads . Finally, there simply weren’t enough roads connecting enough places. People who needed to travel cross-country at this time still took the train; roads were mostly used for local travel.

And so, new roads needed to be built. The car, and therefore the necessary road construction, was a new business. In the beginning, there were no federal organizations to plan and dictate the structures needed for the new automobile. In fact, by 1913 few states had even formed highway departments. It was up to local authorities to figure out how and where to build roads. Concrete and asphalt were soon discovered to be the best materials for the new roads, and local construction escalated. By 1947 there existed a set of U.S. highways that served 209 of 237 cities with populations of 50,000 or more and had a total length of 37,600 miles. In 1956 portions of this system were incorporated and upgraded as part of Eisenhower’s Federal-Aid Highway Act.

Even though the Interstate Highway System continues to be expanded, the last section of the original 1956 plan was completed in 1992 at Glenwood Canyon, Colorado. As of 2004, a section of I-75 north of Atlanta, near the interchange with Interstate 285, has 15 lanes, making it the widest section of the Interstate System. The longest Interstate Highway is Interstate 90, which runs 3,099 miles between Boston, Massachusetts and Seattle, Washington. The heaviest traveled section is Interstate 405 in Los Angeles, California, with approximately 390,000 vehicles a day.