The effect of sprawl on private-vehicle commuting outcomes

Abstract

Amongst the hypothesized beneficial impacts of sprawl on urban quality of life is a decrease in commuting times. Unfortunately, empirical evidence to substantiate the commuting time benefits of sprawl is scant. To address this void in the urban planning literature, a multilevel approach is adopted to study how sprawl affects the duration and length of private-vehicle commutes. Using microdata from the 2001 National Household Transportation Survey for individuals and microdata on various measures of sprawl for metropolitan areas, multilevel models of commuting times and distances are estimated for a subsample of private-vehicle commuters. Results somewhat support the hypothesis that sprawl decreases commuting times for private-vehicle commuters—employment decentralization is associated with shorter commuting times. However, this finding is based on the statistical significance of one of the sprawl measures; not on its practical significance in explaining commuting times which is, in fact, negligible. Coupling this with the finding that the multilevel model only explained about 5% of the variance in private-vehicle commuting times suggests that there is considerable room available for improving the model specification.