The previous post described my intentions to measure urban sprawl by considering the patterns of development in the suburban portions of urban areas. This necessarily requires specifying what aspect of that pattern is associated with degrees of urban sprawl. In other words, I need to define sprawl–a topic on which there has been little agreement.
Some have simply said of sprawl that, like pornography, “I know it when I see it.” Obviously this doesn’t help for measurement. Nor does citing areas as exemplars of sprawl or describing sprawl using aesthetic standards, e.g., ugly development.
Some have defined sprawl as unplanned development. But nearly all jurisdictions in the United States have planning and zoning, yet sprawl certainly is common. So is sprawl development that results from “bad” planning? How would you define this? It better not be planning that leads to sprawl.
Another approach has been to define and measure sprawl based on its causes or consequences. For example, automobile dependency might be seen as an indicator of sprawl. But then how would one account for other consequences of sprawl, say the loss of agricultural land or negative health effects? By saying that automobile dependency is associated with certain patterns of development? But then the patterns of development would seem to take precedence and be the actual indication of sprawl.
I come to the conclusion that sprawl must be defined by some aspects of the pattern of development. And low density and scattered or leapfrog development are most often cited as characteristics of sprawl. Virtually all studies that use a single measure for sprawl have used measures of either density or fragmentation.
And I can take one further step in simplifying things. Scattered development is separated by vacant land. Considering the pattern of development over somewhat larger areas, this vacant land results in low densities. So it is reasonable to take some measures of density for the measurement of urban sprawl.
A full description of my use of multiple measures of housing-unit density for the measurement of sprawl can be found in my paper, “An Alternative Approach to the Measurement of Urban Sprawl” which can be downloaded here.