The beginning and the end of urban population deconcentration in the United States: New insights from application of the Density Distribution Index

《The beginning and the end of urban population deconcentration in the United States: New insights from application of the Density Distribution Index》

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作者: Thomas M. Guterbock

来源: CITIES,Vol.118,Issue1,Article 103349

语言: 英文

关键字: Density gradient;Clark's law;Population deconcentration;Suburbanization;Density Distribution Index;Negative exponential density function

作者单位: Department of Sociology, University of Virginia, P.O. Box 400766, Charlottesville, VA 22904-4766, USA;Department of Sociology, University of Virginia, P.O. Box 400766, Charlottesville, VA 22904-4766, USA

摘要: When did U.S. urban areas begin to experience substantial population deconcentration? Has the deconcentration trend recently ended? These questions have been difficult to answer, in part because many researchers have relied on the density gradient of the negative exponential density-distance function as a valid indicator of population concentration. This article describes an alternative, the Density Distribution Index [DDI], calculated from the density gradient and the central density. Unlike the gradient, the DDI is both mathematically and empirically orthogonal to population size, and thus is unaffected by differing rates of urban growth. This article first calculates DDI scores for metropolitan districts from 1900 to 1970, based on Edmonston's estimates of their density functions (1975). The results indicate that the deconcentration trend took off in earnest at the conclusion of World War II. DDI estimates for SMSAs 1950–1980 (Guterbock, 1990a) show the deconcentration trend continuing strongly through 1980. New density functions are calculated for 119 U.S. urban areas for 1990 to 2015, based on small area data aggregated into annular rings. These data show that average concentration levels 1990–2015 were virtually unchanged. Two-thirds of the urban areas had higher levels of concentration in 2015 than they had earlier, and this was true of over 90% of the largest cities. It can be seen that urban population deconcentration, one of the master trends of the twentieth century, ended for most U.S. urban areas sometime near the start of the twenty-first. The results demonstrate the broader utility of the DDI as a measure of urban concentration.