What was a major effect of the creation of the interstate highway system in the United States?

In 1919, a convoy of army trucks was sent on a journey across the United States, from Washington to San Francisco, to test the efficiency of the roadway system in case of an emergency. It took 62 days for the convoy to cross the nation, underlining the need for better road infrastructures. 1940 marked the opening of the first limited-access divided highway in the United States, the Pennsylvania Turnpike. Once completed, it had a total length of 360 miles and set design and construction standards for future highway developments.

The origins of the Dwight D. Eisenhower National System of Interstate and Defense Highways, commonly known as the Interstate System, can be traced back to 1941, when President Franklin D. Roosevelt appointed a National Interregional Highway Committee to evaluate the need and potential for a national highway system. A system of 33,900 miles of rural routes, plus an additional 5,000 miles of auxiliary urban routes, was recommended. Funding for the system was first authorized in 1952, but the construction of such a massive public and freely accessible infrastructure was beyond the means of the state and federal governments. The first highway segments were thus toll roads. Under President Eisenhower, the question of how to fund the Interstate System was resolved with the enactment of the Federal-Aid Highway Act of 1956, which in addition provided design standards for the system. Construction then proceeded rapidly, and by 1991 the system was considered officially completed. As of 2010, the Interstate system totaled more than 47,100 miles.

Major Interstate routes are designated by one or two-digit numbers. Routes running north and south are assigned odd numbers, while east-west routes are assigned even numbers. For north-south routes, the lowest numbers begin in the west, while the lowest numbered east-west routes are in the south. Thus, Interstate Route 5 (I-5) runs along the West Coast, while I-10 lies along the Mexican border. Interstate I-95 runs along the East Coast, and Interstate I-94 runs parallel to the Canadian border. Several segments of the Interstate are toll roads, particularly in high-density corridors of circulation, and this excludes numerous toll bridges and tunnels that are in operation. About 8.5% of the Interstate system (3,959 miles) is either privatized or managed by state-sponsored trusts (e.g. Pennsylvania Turnpike, New York State Thruway). Most of these toll roads were built in the early 1950s by private or state initiatives and were then incorporated into the Interstate Highway System. The impacts of the Interstate Highway System on the American society (and on others who built comparable structures) were numerous and far-reaching:

• Mobile and motorized society. The Interstate grew in conjunction with the rapid diffusion of the automobile in the 1950s and 1960s, multiplying the mobility of individuals. People were able to exchange greater distances for a similar amount of time spent traveling. This mobility gradually permeated ways of life, and for the first time in history, a large share of the population was able to privately travel over long distances. As such, the automobile and the Interstate quickly became the symbol of individuality, freedom, and opportunities. New activities spurred to service this motorized mobility. A wide range of “drive-in” and “drive-through” activities were created, such as shopping malls, restaurants (e.g. McDonald’s was one of the first restaurant chains to be built to specifically service motorized customers), movie theaters, and even vacationing (e.g. motor inns; road trips).
• Suburbanization. Linking the Interstate with suburbanization must be done carefully since the system was designed to service inter-metropolitan transportation first. However, many Interstate highways by-passed or surrounded (ring roads) major metropolitan areas, giving the impetus to a new form of urban development. Road segments built to service interurban transportation became dominantly used for urban transportation. The emergence of suburbia represents a new landscape with its own economic, social and cultural identity. It illustrates a radical transformation from the traditional urban landscape characterized by collective property (multifamily dwellings) and public transportation. Suburbia is the epitome of private property where each individual was able to own his private “estate” (lot) as a single-family home. For many, suburbanization represented a liberation, since prior to the Interstate, most of the American population rented their housing, mainly as apartment buildings owned by a relatively small group of landlords (the classic movie “It’s a Wonderful Life” underlines this contradiction). Once the Interstate became firmly established, about 65-70% of Americans owned their residence, the largest share of private ownership in the world. This permitted a significant accumulation of wealth in the form of individually and privately owned equity; the pillar of America’s middle class.
• Corridors of circulation. The Interstate favored the creation of large corridors of circulation linking metropolitan areas and permitting the emergence of urban regions, such as Boston-Washington (BosWash). About eight longitudinal and five latitudinal corridors have emerged in the United States, corresponding to the Interstate axis (e.g. I-5, I-15, I-40, I-55, I-70, I-95). More recently, several north-south “NAFTA” corridors have emerged as an axis of long-distance trade in North America, linking more effectively the Canadian and Mexican economies to the American market.
• National comparative advantages. Although prior transport infrastructures, mainly railways, enabled to take advantage of the comparative advantages of the American economy, the Interstate permitted a multiplication of the regional advantages in terms of resources, labor, and markets. In its early stages of development in the 1960s, the Interstate was achieving a rate of return of 35% in terms of economic growth. By the 1990s, this rate had dropped to 10%. The movement of commodities, from raw materials to finished goods, became faster, much cheaper, and flexible (in terms of origin, destination, and scheduling). A whole range of industries emerged to take advantage of the mobility provided by the Interstate, particularly long-distance trucking. New manufacturing regions (e.g. California and several Southern States) emerged outside the traditional industrial belt (Midwest). Freight distribution became a wide-scale activity relying on distribution centers located at accessible (next to an Interstate) locations. This permitted to effectively (in real-time) supply vast consumption markets with a staggering variety of goods coming from all parts of the United States and the World. The big-box store (e.g. Wal-Mart) would not exist in its current form without the Interstate.

A significant caveat related to the Interstate concerns a society that came to rely heavily on the road to satisfy its mobility. The Interstate, for all its advantages and positive impacts, may have geared America on a path of dependency. Despite congestion and a growing reliance on imported oil, few other alternatives are available. Passenger rail, which was a dominant mode of interurban transportation half a century ago, has virtually disappeared. Its market share is taken away on one side by the convenience of the Interstate and on the other by air transportation. Passenger rail remains a significant and available alternative, particularly with high-speed rail systems in other parts of the world, such as Europe, Japan, and China. As the Interstate system ages (about 75% of the system is more than a quarter of a century old), requiring repairs (particularly the 55,000 bridges), the capacity of public agencies to finance them is seriously compromised. It is thus likely that more segments of the system will be privatized, in several cases, to foreign interests. For instance, in 2006, a Spanish-Australian conglomerate paid $3.8 billion to lease the Indiana Toll Road (157 miles of highway) for 75 years. An Australian company bought a 99-year lease on Virginia’s Pocahontas Parkway.