Urban Sprawl

Measures of Sprawl

In the first half of the 20th century, most American cities were relatively compact, built around vibrant central business districts and industrial employment centers, with suburbs limited to those reachable by railroad or streetcar. Residential development typically extended only as far as the distances that could be comfortably walked from public transportation. But in the second half of the century, spurred by the post–World War II building boom and the expanded mobility brought about by increased automobile ownership, land development took on a much more dispersed, less tightly organized character.

Between 1954 and 1997, the amount of developed land in the lower 48 states quadrupled. Census data [Page 850]for the 34 largest metropolitan areas in the United States show that developed land in those areas grew over two and one half times faster than population from 1950 to 1990. The pace accelerated as, in the 1990s, developed land grew 50 percent faster than it had in the 1980s.

Some areas have grown in developed land at particularly impressive rates compared to population. For example, Chicago grew four times faster in land than in population, while Pittsburgh grew some six times faster, from 1982 to 1996. The new development has occurred mostly on forests and farmland, consuming nearly a third of the country's most productive farming regions by 1994, according to the American Farmland Trust. A corresponding trend has been a decline in central city population: In each of the years between 1988 and 1996, central cities in the United States suffered a net out-migration of between 2.4 and 2.9 million people, whereas suburbs experienced a net gain of 2.1 to 3.1 million.

The Consequences of Sprawl

The costs and benefits of these trends to society are hotly debated, but there can be no doubt that, just as increased automobile usage made sprawl possible, the dispersed and disorganized form that sprawl takes has made the automobile more essential to American life. In recent decades, private automobile travel has grown more than three times faster than population, while rates of walking and public transit use have declined. Commuting distances lengthened, and overall miles driven in private automobiles nearly tripled between 1970 and the end of the 20th century, whereas transportation costs overtook food costs as the second largest category of American household spending (after housing).

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