Mapping bicycling exposure and safety risk using Strava Metro

摘要

Overcoming concerns about bicycling safety is critical to increasing the health benefits of bicycling for transportation. While exposure measures are critical for monitoring and understanding bike safety, lack of spatially and temporally detailed bike counts makes it challenging to conduct robust bicycling safety studies. Crowd sourced data from smartphone apps like Strava provide counts for nearly all individual road and trail sections with 1-min temporal resolution. Researchers have found that patterns of Strava bicyclists are similar to all bicyclists in our study area. In this paper, we develop and test a method to normalize bike safety incident hotspots using exposure estimated from Strava data for Ottawa, Canada. We mapped incident hotspots normalized by exposure at increasingly detailed temporal scales. In a dataset with more than more than 8 million Strava activities and 395 incidents (approximately 20,000 Strava activities per incident), adjusting for exposure moved incident hotspots away from protected bike lanes and multi-use paths and onto commercial streets with no bike infrastructure. Strava data are available to correct for exposure where other measures are not available. We encourage researchers, planners, and public health practitioners to consider crowdsourced data to fill exposure data gaps and provide context for interpreting incident data.