Sprawl and Commuting: Exploring New Measures of United States Metro Regions

The degree of connectivity and proximity that results from the configuration of land uses and associated transport networks is an important concept in much of the transportation research agenda. A substantial body of work has developed around the idea that compact, mixed-use development with multimodal transport options will shape travel behavior, increasing the use of transit, walking, and cycling for routine travel. Yet empirical evidence is somewhat mixed. One of the reasons for this uncertainty is the difficulty of defining and measuring sprawl in a meaningful way for use in quantitative analyses, rather than using regionally idiosyncratic or mono-dimensional definitions of sprawl. A recently released national dataset measuring multiple dimensions of urban form offers an opportunity to explore the relationship between transportation and sprawl. This study uses a series of spatial regressions to model effects on the share of a county's workers who commute by driving alone. The results for income are found to be robust across various model specifications, confirming the well-established, positive relationship between income and d riving to work. The results for the Street Accessibility Factor suggest characteristics of the street network are related to the choice to commute by driving alone, with more compact street networks and greater connectivity associated with reduced driving alone. The Land Use Mixing Factor has little power in explaining travel behavior, despite its intuitive appeal as the land use component of the commute mode decision.