Walkability and the American Dream
Upward mobility is strongly correlated with compact, walkable communities — largely in cities but also in suburbs. Low economic mobility is associated with conventional “drive-only” suburbs, according to new data from Arizona State University researchers that builds on a recent study by the Equality of Opportunity Project (EOP).
The EOP study indicated that sprawling metros such as Atlanta, Charlotte, Indianapolis, and Detroit fared poorly in terms of intergenerational income mobility compared to more connected metro areas with higher densities. In a high-profile The New York Times column “Stranded by Sprawl,” economist Paul Krugman theorized that suburban sprawl inhibits job access for young people from low-income households. “Sprawl may be killing Horatio Alger,” he wrote.
In order to test that theory, ASU researchers Emily Talen and Julia Koschinsky examined Walk Scores for 174,186 neighborhood block groups in 359 metro areas included in the EOP study. The researchers had been working for two years on a project involving Walk Scores for block groups — so they had the data in hand.
Walk Score (walkscore.com) is a measure from zero to 100 of accessibility of amenities such as grocery stores, businesses, parks, and schools, to residential units and the street network. It is one of a handful of nationally available databases that serves as a proxy for sprawl or connected neighborhoods.
High Walk Scores don’t necessarily require high density. My house in a single-family neighborhood has a Walk Score of 77, or “very walkable.” Some suburbs achieve high walkability — these can be distinguished from disconnected, spread-out suburbs that are accessible only by automobile. Drive-only suburbs tend to have Walk Scores below 50, categorized as “car-dependent.” In the middle are somewhat walkable places with scores from 50-69.
For the purposes of their analysis, Talen and Koschinsky termed Walk Scores 70 and above as “accessible,” and 69 and below “not accessible.” Every metro region has “accessible” neighborhoods, and some metros boast many hundreds of them. Yet the vast majority (82 percent) of US metropolitan land is not accessible, the researchers note.
Talen and Koschinsky find strong correlations between accessible areas and high income mobility. The measures of absolute mobility, relative mobility, and the odds of reaching the top fifth income category from the bottom fifth all steeply point in that direction (see graph below). A child born to the bottom fifth income group in a walkable neighborhood has a much better chance of becoming financially prosperous than a poor child born in a non-accessible area. “Our results lend support to Dr. Krugman’s hypothesis,” they say.
“The apparent inverse relationship between sprawl and social mobility obviously reinforces the case for ‘smart growth’ urban strategies, which try to promote compact centers with access to public transit,” notes Krugman.
The ASU research also makes Joel Kotkin, a nationally known geographic pundit and smart growth critic, look a bit foolish. On Friday, Kotkin attacked Krugman’s theory and put his own spin on the study.
“The study actually found the highest rates of upward mobility not in dense cities, but in relatively spread-out places like Salt Lake City, small cities of the Great Plains such as Bismarck, N.D.; Yankton, S.D.; and Pecos, Texas — all showed bottom to top mobility rates more than double New York City. And we shouldn’t forget the success story of Bakersfield, Calif., a city Columbia University urban planning professor David King wryly labeled ‘a poster child for sprawl,’ ” wrote Kotkin.
Never mind that New York City (metro population 22 million) can’t be compared in any reasonable way to Bismarck, North Dakota (metro population 120,000). Never mind that the study found that the lowest rates of upward mobility are also in relatively spread-out places. Never mind that cherry picking is always possible in a study of 359 metros with unique economic and social characteristics.
The EOP study found that upward mobility is related to many factors including less inequality in income, better school scores, lower rates of single parenthood and even higher religious affiliation. But the geographic connection to sprawl is now clear, based on the work of Talen and Koschinsky.
This is not a vindication for some metro areas and a condemnation of others. Every US metro has sprawl, and every one has walkable, connected neighborhood fabric. Although Boston, New York, San Francisco, and other dense cities with good transit appear in the top 10 for income mobility in the biggest metros, there are exceptions.
Salt Lake City has high income mobility and a great deal of suburban sprawl. It benefits from unique social characteristics that appear to work against income inequality. Yet Salt Lake City is aggressively working to address its sprawl problem as well. Since 1999 the region has expanded its light rail system and planned multiple, walkable regional centers while the urban core is coming back to life. (UPDATE: As Michael Lewyn points out, "Salt Lake City transit gives more people access to jobs than transit in any other metro area — thus increasing social mobility.")
Cities and towns across America that wish to create dynamic economies and opportunity for children in all walks of life would be wise to improve the neighborhoods connectivity and walkability. As Krugman says, the findings argue for reducing the need for car ownership and improving access to jobs through smart growth practices. That is a realistic and hopeful goal for towns and cities of every size and in every region of the country. Every community has substantial room for improvement. So let's roll up our sleeves and get to work.