A study by Rob Wassmer, a Sacramento State University professor of public policy concludes that reduced auto use has very little effect on suburbanization or urban sprawl. Wassmer conducted a statistical analysis and concluded that a 10 percent reduction in households owning one or more cars would reduce the geographical size of an urban area by only 0.5 percent, and increase population density by only 0.7 percent. Those impacts are far smaller than those produced by other factors that create sprawl.
According to Professor Wassmer, “Natural Evolution” and “Flight from Blight” play much greater roles in generating sprawl. The concept of natural evolution is based on the idea that the older the housing stock is, the less likely households are to choose a location because households tend to prefer newer housing and most affordable new housing is built in suburban locations. Flight from blight is people dispersing to new neighborhoods on the metropolitan fringe to escape the real and/or perceived blight of the central places in urban areas.
A reduction in per capita income, an increase in the percentage of wealthy households, and a reduction in the percent of an urban area’s central places that are poor, all have demonstrably greater effects on controlling sprawl than reduced automobile use, Wasserman concluded, stating, “Land use is largely the cause of auto use, not the other way around."