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Interstate Density Map

Celebrating the Eisenhower Interstate Highway System

The Changing Face of America

The map series below shows the progression of the Interstate System, decade by decade. As the progression illustrates, the Interstate System was essentially complete by the 1980s. The map series shows that while population remains dense in the Northeast, Mid-Atlantic, and Middle West, the Sunbelt States experience dramatic gains in population. The trends illustrated in the map series, and the broader changes in our society during the Interstate decades, were not caused by the Interstates, but the efficiency and flexibility of our transportation network—with the Interstates as the backbone—supported the shifts and helped society absorb such drastic changes while becoming stronger and more cohesive than ever. Read More

The Changing Face of America

As he looked back on his two terms in office, former President Dwight D. Eisenhower said of the Interstate System that, "More than any single action by the government since the end of the war, this one would change the face of America."  The impacts of the Interstate System remain controversial, but it did, as President Eisenhower predicted, change the face of America—not simply by altering the landscape during construction, but by supporting changes that transformed our society in the second half of the 20th century.

The first decade of Interstate construction was the most intense period of road building in history.  Half of the Interstate System as then designated was open by the end of 1966, and by the 1970s, enough Interstate roadway was on the ground that the changes President Eisenhower had predicted began to occur.  The accompanying map series shows the progression of the Interstate System, decade by decade.  As the progression illustrates, the Interstate System was essentially complete by the 1980s. Interstate motorists faced few gaps as they traveled around the country. 

Even with such a massive, transformational public work, its impacts on the country are hard to separate from the effects of other events swirling through society, sometimes in harmony with the Interstates, and sometimes not.  One of the more dramatic changes since the 1950s involves the geographic distribution of our population.  Transportation consultant and demographics expert Alan Pisarski described the population shifts in a chapter on "US Roads" in Millennium Book, (International Road Federation, 2001).  He explained that:

There has been a pronounced "sunbelt shift" to population, with over 90% of national growth in the eighties going to the South and the West, at the expense of the older, more settled regions of the Midwest and Northeast.  The South and West now have more than 56% of the nation's population.

The map series shows that while population remains dense in the Northeast, Mid-Atlantic, and Middle West, the Sunbelt States experience dramatic gains in population. 

Pisarski pointed out how these broad changes were accompanied by changes in metropolitan areas:

  • Since 1950 metropolitan areas have grown from 56% of national population to 80%.
  • All of the growth in metropolitan areas in the eighties occurred in suburban areas, as central cities actually declined in population.
  • Metropolitan areas were roughly 50% suburban and 50% urban in 1950; now that ratio is closer to two-thirds suburban, and is rising. 
  • Despite the emphasis on metropolitan areas, metropolitan areas are losing population to non-metropolitan areas, often to those rural areas on the fringes of metropolitan complexes.

The maps also illustrate another of Pisarski's observations, namely that, "More than half of national growth continues to be in three states, California, Texas, and Florida."  The Interstate System has helped these States accommodate the population influx. 

During the signing ceremony on October 15, 1966, for the legislation creating the U.S. Department of Transportation, President Lyndon B. Johnson said, "In large measure, America's history is a history of her transportation."  The trends illustrated in the map series, and the broader changes in our society during the Interstate decades, were not caused by the Interstates, but the efficiency and flexibility of our transportation network—with the Interstates as the backbone—supported the shifts and helped society absorb such drastic changes while becoming stronger and more cohesive than ever.  As President Johnson's observation suggests, the history of the past 50 years is, in part, a history of the Dwight D. Eisenhower National System of Interstate and Defense Highways and how it has joined with the broader forces of society to change the face of America.    

 





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