Land use and travel behavior

Exploring the nonlinear relationship between the built environment and active travel in the Twin Cities

Tao Tao, Xinyi Wu, Jason Cao, Yingling Fan, Kirti Das, and Anu Ramaswnmi, 2023. Journal of Planning Education and Research, 43(3), 637-652.

Active travel is important to public health and the environment. Previous studies substantiate built environment influences active travel, but they seldom assess its overall contribution. Most of the studies assume that built environment characteristics have linear associations with active travel. This study uses Gradient Boosting Decision Trees to explore nonlinear relationships between the built environment and active travel in the Twin Cities. Collectively, the built environment has more predictive power for active travel than demographics, and parks, proximity to downtown, and transit access have important influences. The threshold effects of built environment variables help inform planning practice.


Exploring nonlinear and collective influences of regional and local built environment characteristics on travel distances by mode

Tao Tao and Jason Cao, 2023. Journal of Transport Geography, 109, 103599.

We examined the nonlinear associations of the built environment with travel distances by driving, transit, and active travel and compared the relative contributions of local and regional built environment characteristics through applying gradient boosting decision trees to regional travel survey data in the Twin Cities, US. We identified the common thresholds of built environment characteristics associated with the three travel distances and inform planners of the efficient allocation of limited resources to planning efforts at different scales. We found prevalent threshold associations between built environment characteristics and travel distances. The thresholds suggest the common ranges of built environment characteristics that optimize the reduction of driving and the promotion of transit and active travel. For example, job accessibility should be larger than 800 thousand jobs within 20-min of driving and distance to downtown Minneapolis should be within 10 miles. The results also showed that regional characteristics collectively have a stronger influence on all three distances than local characteristics. The findings on transit and active travel differ from the common understanding in the literature. This study suggests that planners should pay more attention to metropolitan-scale planning and deploy programs that enhance regional accessibility.


Exploring nonlinear built environment effects on driving with a mixed-methods approach

Tao Tao and Petter Næss, 2022. Transportation Research Part D: Transport and Environment, 111, 103443.

Recent studies have been exploring the complex nonlinear relationships between built environment attributes and driving using machine learning approaches. However, these nonlinear relationships lack causal explanations. This study applied a mixed-methods approach to data from a smaller European city, Stavanger, Norway. Our results showed that transport rationales for choosing activity locations and travel modes, along with configurations of the jobs and other facilities, provide causal explanations for the nonlinear and threshold effects of built environment attributes on people’s driving-related behavior. Distance to city center plays the most important role and its nonlinear relationship reflects the influence of the polycentric city structure of Stavanger on driving. For Stavanger and similar cities, compact development around the city center helps to rein the auto dependence. Furthermore, the thresholds of nonlinear relationships provide planning guidelines to support compact development policies.


Examining motivations for owning autonomous vehicles: Implications for land use and transportation

Tao Tao and Jason Cao, 2022. Journal of Transport Geography, 102, 103361.

Illustrating the associations between built environment characteristics and autonomous vehicle (AV) ownership helps policymakers understand where AVs emerge first and their impacts on society. However, few studies have addressed interest in AV ownership from the spatial perspective. Using regional travel survey data from the Twin Cities, we applied the gradient boosting decision tree method to test three hypotheses (diffusion of innovation, efficiency, and modal substitution) underlying the relationships between respondents’ interest in owning AVs and its correlates. Results showed that the innovation-diffusion hypothesis dominates the motivations for owning AVs, followed by preference for efficiency and then modal substitution. However, its associations with built environment variables suggest more of preference for efficiency than of diffusion of innovation and modal substitution. Population density, road connectivity, and land use entropy are negatively associated with the interest. The results provide suggestions to address the externalities of AVs in different areas.