Did U.S. highways cause suburbanization?

Between 1950 and 1990, while the population of U.S. metropolitan areas grew 72%, the central cities shrank by 17%. Factors that could account for central cities’ population decline include faster commutes, population sorting due to racial and social preferences and perceived increases in city crimes.

A 2007 Brown University paper published in the Quarterly Journal of Economics, “Did Highways Cause Suburbanization?” examines the extent to which highways can explain different rates of suburbanization across decades within U.S. metropolitan areas. The paper’s author calculates that:

• Had the interstate highway system not been built, aggregate central city population would have grown by about 8% (instead of declining by 17%) between 1950 and 1990.
• Central city population would have increased by an additional 3% had limited-access highways (that are not part of the interstate system) not been built.
• The decline in aggregate central city population was considerably more pronounced in inland central cities.

Tags: cars, mass transit, infrastructure