Assess the non-linear relationship between built environment and active travel around light-rail transit stations

Active travel is promoted in transit-oriented development to reduce the negative outcomes of urban sprawl, such as traffic congestion and obesity. This article examines the impacts of the built environment on walking and biking trip generation around transit stations through a study of SLCo, Utah. A regression tree method is employed. The results suggest that the threshold-based model can better capture the relationship between built environment factors and people's active travel behavior. Further analysis identifies the relative importance of different built environment factors. The retail floor area ratio is the primary determinant of walking trip generation, and dwelling density is crucial to biking trip generation. A combined regression tree model highlights the significance of urban amenity accessibility in improving walkability and bikability simultaneously around transit stations. These outcomes provide insights into the non-linear relationship between built environment factors and walking/biking trip generation around transit stations. The relative importance of the built environment factors revealed by the regression tree models is also helpful to future TOD practice.