Doing the Math on Sprawl | News | Pittsburgh | Pittsburgh City Paper

Doing the Math on Sprawl

Academics from Toronto and London have finally proven scientifically what visitors to Cranberry have long suspected: Pittsburgh tops the nation in sprawl. They presented their findings in the May issue of the Quarterly Journal of Economics in a paper called "Causes of Sprawl: A Portrait from Space."


The authors looked at aerial photos and satellite data and divided the continental United States into 8.7 billion 30-meter-square data cells. They calculated how much open space surrounded each house in each cell to determine the level of sprawl ... and in the process, found that Pittsburgh was the most spread out.


Explains study co-author Matthew Turner of the University of Toronto, Pittsburgh's perfect storm of hilly geography and lots of available groundwater led people to spread out far and wide, developing outside the city while leaving the city proper to decay. Hillsides don't lend themselves to building: The study found that increases in hilliness equal an increase in sprawl, and that most of Pittsburgh is hillier than most other places. Available ground water lets people dig wells, a relatively inexpensive, one-time expense, as opposed to laying pipe long distances and paying to bring in municipal water.


Turner says that the debate about sprawl has been raging for years, but without any hard-and-fast data. He was inspired to attempt to quantify sprawl after a frustrating battle trying to cross six lanes of highway traffic on foot: He was trying to get to a sandwich shop across from a hotel he was staying at in Arkansas years ago.


"People talk in hysterical language about McMansions and Wal-Mart," Turner says. "It doesn't lend itself to a constructive policy debate."


The data in the study, he says, can allow new debates about land use and urban planning.

"People have been eager to rush to policy prescriptions without a very good understanding of the underlying phenomena," says Turner. "We wanted to try to put the policy discussion on sounder footing." The study doesn't answer the question of whether sprawl is hurtful, but it does allow the debate to be framed differently ... other data, like road use or infrastructure costs, can be examined relative to sprawl.


Turner is careful not to criticize sprawl outright.


"There's a lot of different kinds of people out there, people who want to live in McMansions and drive to work, and people who want to live in condos and walk to work," he says. "Nobody's right. People are allowed to want different things."


Court Gould, director of Sustainable Pittsburgh, a public-policy advocacy group, says the study results don't surprise him. While sprawl is not inherently bad, he allows, it is bad for Pittsburgh. In a city with population growth, suburban flight doesn't harm the urban hub. But Pittsburgh's population loss means that people who make for the great sprawling yonder aren't being replaced in the city center, leading to blight and disuse.


Also, he says, skyrocketing fuel costs are leading more and more people to use public transportation, and not every far-flung suburb can be served by transit.


Concludes Gould: "We're growing on the fringe and hollowing out the core."


Download the paper and view maps at

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