Land-use planners across the country have long defined "urban sprawl" as something that happens in the lightly populated exurban fringes of cities, where it's easy to see the isolated tracts of similar-looking housing, the strict segregation of commercial and residential areas and the congested highways.
But residents of closer-in areas also say they "feel" those characteristics of sprawl in their neighborhoods despite their higher population densities, and a University of Minnesota researcher says a study she performed indicates their perception in many cases is indeed more than just a feeling.
Tracy Kugler, a research project manager with the University's Minnesota Population Center, has developed a new way to measure urban sprawl that incorporates a series of "know-it-when-you-see-it" attributes of sprawl — rather than just population density — and then applied it to nearly every major urban center in the United States.
She deployed her "sprawl index" on a neighborhood scale across 353 U.S. metropolitan regions, which is a departure for a discipline in which sprawl has almost always been studied on a regional scale.
What Kugler found in her two-year effort is that moderately dense neighborhoods often share the same sprawl-related characteristics as their exurban counterparts, which could prove to be an eye-opener for planners who have mostly assumed that these issues are confined to outer-ring areas.
"I wanted to find a way to measure what people actually experience as sprawl, and how that compared to what people had been measuring as sprawl," she said. "The sense that I had was that density isn't the only thing that matters."
In developing her index, Kugler used public data on things that people typically perceive as attributes of sprawl, such as the level of street network connectivity, the integration of housing and commercial uses and the sameness of the housing stock.
She also employed aerial photography of a randomly selected cross section of neighborhoods from across the country to determine whether they had small or large lots, if there were sharp or blurry transitions between urban and rural uses, the number of cul-de-sac streets and other criteria.
Then, using a mathematical algorithm, each neighborhood was assigned a "sprawl index" of between 1 and 6 and compared to their population densities.
What the study showed is that density and the presence of sprawl-related attributes were not closely related — confirming the feelings of residents of closer-in neighborhoods that even though there were plenty of other people around, they still can suffer from the ills of urban sprawl.
"You can have a moderate-density neighborhood that — depending on whether it has well-connected street networks, public transit, commercial uses such as grocery stores, schools and offices — can still be 'sprawling,' " Kugler said.
The findings pointed out that neighborhood-level "smart growth" urban planning — favoring a variety of housing types, walking-distance schools, shopping and well-connected streets — has a significant impact on the bigger urban sprawl picture, she added.
"It really emphasizes the importance of mixed uses, transportation choices and accessibility," she said.
The Metropolitan Council, which is tasked by the state to tame urban sprawl in the Twin Cities, is aware that density is just one of the factors that needs to be considered in its efforts to plan for better mobility, spokeswoman Bonnie Kollodge said.
She pointed to the council's 2011 report to the state Legislature in which it concluded that land use and transportation planning should be carried out together, rather than separately as they are now, in order to truly help reduce congestion on the metro area's streets and freeways.
Carving out higher-density, mixed-use areas in existing neighborhoods can, by itself, have a "modestly" helpful effect, but for maximum impact density needs to be "combined with other strategies, such as connections to major centers, a high-quality local transportation network, a mix of land uses, and transit," the report said.
Don Jacobson is a Twin Cities freelance writer.
