This paper conceptually and empirically explores the complex relationshipbetween congestion and accessibility. While congestion alters individualaccess to opportunities, its effects vary significantly across people, places, and time, variations that remain relatively understudied. This paper begins by proposing a conceptual framework with three components. First, congestion can constrain mobility and thus indirectly reduce accessibility. Second, congestion is associated with agglomerations of activity and with increased accessibility. Finally, congestion is in part a phenomenonof perception and behavior, cognitively altering an individual’s choice set of destinations and altering actual access to opportunities. Congestionand individual travel data for the Los Angeles region are used to explorethe localized spatial relationship between congestion and accessibility. As the multifaceted framework suggests, congestion does not have a uniformeffect on accessibility, but varies substantially by neighborhood. Some neighborhoods appear to be more “congestion adapted” than others by allowing high levels of activity participation despite high levels of congestion. To account for personal characteristics such as income that may influence the spatial analysis, this paper also constructs a model of the number of daily trips as a function of an array of personal and household characteristics. Residuals from the model suggest that place-based neighborhood effects explain the relatively higher levels of travel by residents found inthe “congestion adapted” neighborhoods.
Abstract