Interstate Highway System
The Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate Highway System, or the Eisenhower Interstate System, is a network of controlled-access highways that forms part of the National Highway System in the United States. The system extends throughout the contiguous United States and has routes in Hawaii, Alaska, and Puerto Rico.
In the 20th century, the United States Congress began funding roadways through the Federal Aid Road Act of 1916, and started an effort to construct a national road grid with the passage of the Federal Aid Highway Act of 1921. In 1926, the United States Numbered Highway System was established, creating the first national road numbering system for cross-country travel. The roads were funded and maintained by U.S. states, and there were few national standards for road design. United States Numbered Highways ranged from two-lane country roads to multi-lane freeways. After Dwight D. Eisenhower became president in 1953, his administration developed a proposal for an interstate highway system, eventually resulting in the enactment of the Federal-Aid Highway Act of 1956.
Unlike the earlier United States Numbered Highway System, the interstates were designed to be all freeways, with nationally unified standards for construction and signage. While some older freeways were adopted into the system, most of the routes were completely new. In dense urban areas, the choice of routing destroyed many well-established neighborhoods, often intentionally as part of a program of "urban renewal". In the two decades following the 1956 Highway Act, the construction of the freeways displaced one million people, and as a result of the many freeway revolts during this era, several planned Interstates were abandoned or re-routed to avoid urban cores.
Construction of the original Interstate Highway System was proclaimed complete in 1992, despite deviations from the original 1956 plan and several stretches that did not fully conform with federal standards. The construction of the Interstate Highway System cost approximately $114 billion. The system has continued to expand and grow as additional federal funding has provided for new routes to be added, and many future Interstate Highways are currently either being planned or under construction.
Though heavily funded by the federal government, Interstate Highways are owned by the state in which they were built. With few exceptions, all Interstates must meet specific standards, such as having controlled access, physical barriers or median strips between lanes of oncoming traffic, breakdown lanes, avoiding at-grade intersections, no traffic lights, and complying with federal traffic sign specifications. Interstate Highways use a numbering scheme in which primary Interstates are assigned one- or two-digit numbers, and shorter routes which branch off from longer ones are assigned three-digit numbers where the last two digits match the parent route. The Interstate Highway System is partially financed through the Highway Trust Fund, which itself is funded by a combination of a federal fuel tax and transfers from the Treasury's general fund. Though federal legislation initially banned the collection of tolls, some Interstate routes are toll roads, either because they were grandfathered into the system or because subsequent legislation has allowed for tolling of Interstates in some cases.
, about one quarter of all vehicle miles driven in the country used the Interstate Highway System, which has a total length of. In 2022 and 2023, the number of fatalities on the Interstate Highway System amounted to more than 5,000 people annually, with nearly 5,600 fatalities in 2022.
History
Planning
The United States government's efforts to construct a national network of highways began on an ad hoc basis with the passage of the Federal Aid Road Act of 1916, which provided $75 million over a five-year period for matching funds to the states for the construction and improvement of highways. The nation's revenue needs associated with World War I prevented any significant implementation of this policy, which expired in 1921.In December 1918, E. J. Mehren, a civil engineer and the editor of Engineering News-Record, presented his "A Suggested National Highway Policy and Plan" during a gathering of the State Highway Officials and Highway Industries Association at the Congress Hotel in Chicago. In the plan, Mehren proposed a system, consisting of five east–west routes and 10 north–south routes. The system would include two percent of all roads and would pass through every state at a cost of, providing commercial as well as military transport benefits.
In 1919, the US Army sent an expedition across the US to determine the difficulties that military vehicles would have on a cross-country trip. Leaving from the Ellipse near the White House on July 7, the Motor Transport Corps convoy needed 62 days to drive on the Lincoln Highway to the Presidio of San Francisco along the Golden Gate. The convoy suffered many setbacks and problems on the route, such as poor-quality bridges, broken crankshafts, and engines clogged with desert sand.
Dwight Eisenhower, then a 28-year-old brevet lieutenant colonel, accompanied the trip "through darkest America with truck and tank," as he later described it. Some roads in the West were a "succession of dust, ruts, pits, and holes."
As the landmark 1916 law expired, new legislation was passed—the Federal Aid Highway Act of 1921. This new road construction initiative once again provided for federal matching funds for road construction and improvement, $75 million allocated annually. Moreover, this new legislation for the first time sought to target these funds to the construction of a national road grid of interconnected "primary highways", setting up cooperation among the various state highway planning boards.
The Bureau of Public Roads asked the Army to provide a list of roads that it considered necessary for national defense. In 1922, General John J. Pershing, former head of the American Expeditionary Force in Europe during the war, complied by submitting a detailed network of of interconnected primary highways—the so-called Pershing Map.
A boom in road construction followed throughout the decade of the 1920s, with such projects as the New York parkway system constructed as part of a new national highway system. As automobile traffic increased, planners saw a need for such an interconnected national system to supplement the existing, largely non-freeway, United States Numbered Highways system. By the late 1930s, planning had expanded to a system of new superhighways.
In 1938, President Franklin D. Roosevelt gave Thomas MacDonald, chief at the Bureau of Public Roads, a hand-drawn map of the United States marked with eight superhighway corridors for study. In 1939, Bureau of Public Roads Division of Information chief Herbert S. Fairbank wrote a report called Toll Roads and Free Roads, "the first formal description of what became the Interstate Highway System" and, in 1944, the similarly themed Interregional Highways.
Federal Aid Highway Act of 1956
The Interstate Highway System gained a champion in President Dwight D. Eisenhower, who was influenced by his experiences as a young Army officer crossing the country in the 1919 Motor Transport Corps convoy that drove in part on the Lincoln Highway, the first road across America. He recalled that, "The old convoy had started me thinking about good two-lane highways... the wisdom of broader ribbons across our land." Eisenhower also gained an appreciation of the Reichsautobahn system, the first "national" implementation of modern Germany's Autobahn network, as a necessary component of a national defense system while he was serving as Supreme Commander of Allied Forces in Europe during World War II. In 1954, Eisenhower appointed General Lucius D. Clay to head a committee charged with proposing an interstate highway system plan. Summing up motivations for the construction of such a system, Clay stated,Clay's committee proposed a 10-year, $100 billion program, which would build of divided highways linking all American cities with a population of greater than 50,000. Eisenhower initially preferred a system consisting of toll roads, but Clay convinced Eisenhower that toll roads were not feasible outside of the highly populated coastal regions. In February 1955, Eisenhower forwarded Clay's proposal to Congress. The bill quickly won approval in the Senate, but House Democrats objected to the use of public bonds as the means to finance construction. Eisenhower and the House Democrats agreed to instead finance the system through the Highway Trust Fund, which itself would be funded by a gasoline tax. In June 1956, Eisenhower signed the Federal Aid Highway Act of 1956 into law. Under the act, the federal government would pay for 90 percent of the cost of construction of Interstate Highways. Each Interstate Highway was required to be a freeway with at least four lanes and no at-grade crossings.
The publication in 1955 of the General Location of National System of Interstate Highways, informally known as the Yellow Book, mapped out what became the Interstate Highway System. Assisting in the planning was Charles Erwin Wilson, who was still head of General Motors when President Eisenhower selected him as Secretary of Defense in January 1953.
Construction
Some sections of highways that became part of the Interstate Highway System actually began construction earlier.Three states have claimed the title of first Interstate Highway. Missouri claims that the first three contracts under the new program were signed in Missouri on August 2, 1956. The first contract signed was for upgrading a section of US Route 66 to what is now designated Interstate 44. On August 13, 1956, work began on US 40 in St. Charles County.
Kansas claims that it was the first to start paving after the act was signed. Preliminary construction had taken place before the act was signed, and paving started September 26, 1956. The state marked its portion of I-70 as the first project in the United States completed under the provisions of the new Federal-Aid Highway Act of 1956.
The Pennsylvania Turnpike could also be considered one of the first Interstate Highways, and is nicknamed "Grandfather of the Interstate System". On October 1, 1940, of the highway now designated I‑70 and I‑76 opened between Irwin and Carlisle. The Commonwealth of Pennsylvania refers to the turnpike as the Granddaddy of the Pikes, a reference to turnpikes.
Milestones in the construction of the Interstate Highway System include:
- October 17, 1974: Nebraska becomes the first state to complete all of its mainline Interstate Highways with the dedication of its final piece of I-80.
- October 12, 1979: The final section of the Canada to Mexico freeway Interstate 5 is dedicated near Stockton, California. Representatives of the two neighboring nations attended the dedication to commemorate the first continuous freeway connecting the North American countries.
- August 22, 1986: The final section of the coast-to-coast I-80 is dedicated on the western edge of Salt Lake City, Utah, making I-80 the world's first continuous freeway to span from the Atlantic to Pacific Ocean and, at the time, the longest continuous freeway in the world. The section spanned from Redwood Road to just west of the Salt Lake City International Airport. At the dedication it was noted that coincidentally this was only from Promontory Summit, where a similar feat was accomplished nearly 120 years prior, the driving of the golden spike of the United States' First transcontinental railroad.
- August 10, 1990: The final section of coast-to-coast I-10 is dedicated, the Papago Freeway Tunnel under downtown Phoenix, Arizona. Completion of this section was delayed due to a freeway revolt that forced the cancellation of an originally planned elevated routing.
- September 12, 1991: I-90 becomes the final coast-to-coast Interstate Highway to be completed with the dedication of an elevated viaduct bypassing Wallace, Idaho, which opened a week earlier. This section was delayed after residents forced the cancellation of the originally planned at-grade alignment that would have demolished much of downtown Wallace. The residents accomplished this feat by arranging for most of the downtown area to be declared a historic district and listed on the National Register of Historic Places; this succeeded in blocking the path of the original alignment. Two days after the dedication residents held a mock funeral celebrating the removal of the last stoplight on a transcontinental Interstate Highway.
- October 14, 1992: The original Interstate Highway System is proclaimed to be complete with the opening of I-70 through Glenwood Canyon in Colorado. This section is considered an engineering marvel with a span featuring 40 bridges and numerous tunnels and is one of the most expensive rural highways per mile built in the United States.