Simultaneous Modeling of Endogenous Influence of Urban Form and Public Transit Accessibility on Distance Traveled

This paper describes an attempt to understand better the endogenous relationships between urban form, accessibility to public transit, and daily travel distance. A model of two simultaneous equations was implemented. The model took into account the interaction between the ownership of vehicles and the choice of household location as explanatory endogenous variables for total distance traveled by respondents. Choice of household location was defined on the basis of cluster analysis (neighborhood typology) driven by land use mix, population density, and accessibility to transit. With socioeconomic variables controlled for, the impacts of neighborhood typologies combined with car ownership levels as endogenous choices were estimated with the use of a model with simultaneous equations. This research used data from the Quebec City, Quebec, Canada, origin destination survey conducted in 2001. The data set included responses from more than 50,000 individuals. Among other results, the presence of endogeneity was confirmed. When endogeneity was not taken into account, the joint effects of car ownership and household location choices were underestimated. According to the model with simultaneous equations, the total distance traveled by individuals was primarily influenced by employment status and household structure. In fact, the total distance per individual had an average rate of growth of 50% when the individual was working full-time. The distance also increased by 5.7% per child and decreased by 2.4% per person. Although the elasticities of urban form and transit supply variables introduced individually into the model were small, the elasticities of neighborhood type as endogenous variables were much more relevant.