Study Ranks Metro Areas by Sprawl

A new report ranks U.S. metro areas by how compact and connected they are, linking development policies to higher life expectancy and chances of upward mobility for residents.

Researchers from the University of Utah’s Metropolitan Research Center and Smart Growth America, an organization that advocates for sustainable growth, followed up their 2002 report on suburban sprawl by expanding the number of areas included and finding correlations between rankings and quality of life measures.

The report measures 221 metropolitan areas and 994 counties using 2010 statistics in four key areas: residential and employment density, diversity of land use, the proportion of people and businesses located near each other and measures of physical infrastructure, such as the average length of street blocks and the percentage of four-or-more-way intersections.

Since the original 2002 report, a growing body of research has linked development that encourages communities to spread out across great geographical distances to obesity, traffic fatalities, inefficient energy use, even depression.

Researchers weighed the four factors equally, producing an index with an average of 100, meaning metro areas that scored above that tend to be more compact while those scoring below 100 are more sprawling.

The report cautioned against making comparisons between the two decades because the lines of metropolitan statistical areas change, sometimes dramatically.

Four California cities made the top 10 list, with San Francisco ranking second. But the New York City metro area, which stretches into New Jersey, ranked first. Atlantic City finished third, while Trenton finished seventh. Illinois cracked the top 10 list twice, with Champaign at fifth and Springfield at 9th.

The rankings change, though, when controlling for population. For example, Miami jumps to third when filtering for metro areas with populations that exceed one million. Madison, Wis., finished first among medium-sized metro areas, defined as places with populations between 500,000 and one million people.

The most sprawling metro areas, on the other hand, came mostly from the South. Atlanta ranked first on the sprawl list, and the South claimed seven of the top 10. Reid Ewing, a professor of urban planning at the University of Utah, attributed the region’s greater sprawl to cultural values that are less focused on “ecological friendly development,” different investment strategies and a lack of geographical barriers to growth.

“Atlanta can sprawl outward pretty much without limitation,” he said. “Simply the availability of low-cost land at increasing distances may account for some of it.”

Using existing data, researchers also concluded there’s a direct relationship between compactness and economic mobility, finding that a 10-percent increase in a metro area’s overall index score translates to a 4.1 percent increase in the chances a child born in the bottom 20 percent of income distribution reaches the top 20 percent by age 30. Researchers also found that life expectancy increases by about four percent every time an overall index score doubles.

Read the full study here.

Sprawl Index Data

The following table lists Smart Growth's Sprawl Index rankings. Data shown are for metro areas unless otherwise indicated.