How does Regional Air Pollution affect Pedestrian, Car, and Transit Use?

To examine how regional air pollution affects multimodal traffic volumes, we analyzed two years (2018–2019) of daily automobile traffic counts, estimated pedestrian volumes, and transit ridership in Cache County, Utah, United States. Multilevel models accounted for locational differences while controlling for weather and other temporal variables. When the air quality was poor, pedestrian volumes decreased, automobile traffic increased, and system-wide bus ridership showed no significant change. Walking declines were larger in neighborhoods with higher car ownership and smaller in areas with greater street connectivity and more commercial land use.