Professor Jason Cao and Tao Tao (PhD '22), currently a postdoc researcher at Carnegie Mellon University, published the paper, “Exploring nonlinear and collective influences of regional and local built environment characteristics on travel distances by mode,” in the Journal of Transport Geography. This work was funded by the University of Minnesota Doctoral Dissertation Fellowship.

Using gradient boosting decision trees to regional travel survey data in the Twin Cities, US, this study 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. 

This study identified the common thresholds of built environment characteristics associated with the three travel distances and informed planners of the efficient allocation of limited resources to planning efforts at different scales. This study 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.

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.