Archive for the ‘Urban sprawl’ Category

The Metropolitan Environment and Health: The Impact of Income Inequality, Racial Segregation and Urban Sprawl on the Risk of Physical Inactivity

Thursday, February 14th, 2013



Physical inactivity is a risk factor for obesity, cardiovascular disease and premature mortality. But despite health warnings, many Americans remain inactive.




The data source was the 2001 Behavioral Risk Factor Surveillance System, a telephone survey of US adults.  Respondents living in all metropolitan areas defined in 2000 were included.  This study used multilevel analysis combining metropolitan level factors:  income inequality (GINI Index), Black-White residential segregation (Dissimilarity Index), urban sprawl (the Urban Affairs Review Sprawl Index) and per capita income along with individual level factors:  sex, age, income, race/ethnicity and education.  The risk of being physically inactive was compared to meeting current CDC guidelines for physical activity.




The final sample consisted of 121,894 adults in 315 metropolitan areas.  In the full multivariate analysis, increased levels of income inequality (odds ratio: 1.052, 95% CI = 1.033, 1.072), segregation (1.008, 95% CI = 1.005, 1.012) and urban sprawl (1.006, 95% CI = 1.003, 1008) were associated with an increased risk of physical activity.




Addressing the physical activity, and its health consequences, may require attention to the structural characteristics of the metropolitan environment.  While recent research highlights the role of the built environment as affecting inactivity, this study suggests that the social environment is also an important predictor of inactivity.

A history of urban sprawl

Thursday, January 10th, 2013

We know that people in the United States have been moving to the edges of cities and metropolitan areas for centuries. See Robert Bruegann’s A Compact History of Sprawl or Dolores Hayden’s Building Suburbia for the details of this history.  Even the post World War II era saw several waves of suburban development development that Hayden characterized as sitcom suburbs and edge cities. The end of the century saw extreme commutes with a lot of development in what are now often referred to as exurbs.

But what we don’t know is how much sprawl has been occurring over the past many decades and whether these trends are continuing at a steady pace, accelerating, or decelerating. One very imprecise measure is the proportion of people living in suburbs versus center cities, but this tells us very little  because some suburbs are very dense and sone central cities contain large areas of low density development. For example, some suburbs are denser than their center cities: Somerville, MA and Daly City, CA are two.  Other cities, such as Phoenix and Houston, have very low density areas within their city limits (not to mention the issue with measures for consolidated cities an counties).

A problem with many sprawl measures is that they’re relative measures. Even if you could calculate them for multiple years, they would not tell you how sprawl changed in that particular metro area.

So one project I am working on is to calculate sprawl for every metro area for each census year from 1970 to 2010. This uses a measure developed by my colleague Pat Hynes and me that is based on the difference between the proportion of a metropolitan area’s high density and low density population. A measure I call the Density Balance Sprawl Index.

The results, almost ready for publication, will surprise many people. Stay tuned.

Toronto Parklets

Monday, December 10th, 2012

The City of Toronto has done a great job of adding some action to Yonge Street, which needs it.  The street suffers from the deadening influence of Eaton Center, a 1970s era downtown shopping mall complete with fortress like facades on Yonge.  Going north, the street is lined with strip clubs and my personal favorite, discount sushi restaurants (that was sarcastic).  Here are some of the parklets:


Urban Sprawl 1970 – 2000

Thursday, February 3rd, 2011

In preparation for the 2010 Census data release next month, I have recalculated urban  sprawl values for every US metropolitan area using 2010 definitions of metropolitan areas.  The 1970 – 2000 data is available here:

1970 – 2000 Urban sprawl data

The data provided here have a high correlation with the Smart Growth America data.  Basically, the value here represents the percent of a metropolitan area’s population living in low density (< 3,500 persons per square mile) census tracts.  Rural areas of metro areas (population density < 200 persons per square mile) are excluded.

2010 values once the 2010 data become available.