Cool routes: Assessing how green space and paved paths modify heat's effects on urban bicycling

Understanding how heat's effect on bicycling varies spatially across the urban environment can inform who may be bicycling in the heat and how urban-planning measures can improve thermal comfort for bicyclists. We estimated effects of heat on recreational and commute bicycling in Denver, Colorado, USA using city-wide, finely resolved bicycling data and assessed heterogeneity in effects by area-level social vulnerability and proximity to the city center and whether off-street paths and green-space measures, if intervened upon, modify these effects. From Strava Metro, we obtained daily data on recreational and commute bicycling in Denver on each street segment (N = 218,641) during the summer months of 2019–2023. We estimated effects of hot (95–99 °F [35–37 °C]) and very hot (100–104 °F [38–40 °C]) temperature on daily bicycling using model-based standardization, controlling for temporally varying confounders. We assessed effect heterogeneity by area-level social vulnerability and proximity to the city center. To assess effect modification by intervention (defined in text) of paved paths and green-space measures, we additionally controlled for social vulnerability and proximity to the urban core. Heat's attenuating effects on recreational and commute bicycling were stronger in central Denver but did not differ across area-level social vulnerability. Heat's attenuating effects were somewhat weaker on off-street paths and considerably weaker in greener areas and near blue space. Results support the provision of paved paths and access to green and blue space to support bicycling during hot weather. • Heat's attenuating effect on bicycling was weaker in central Denver. • Paved paths mitigated heat's attenuating effect on bicycling. • Greenness and proximity to water also mitigated heat's attenuating effect on bicycling. • Cool corridors – paved paths near greenness or water – may improve bicyclist comfort in heat.