Bicycle Safety Investigation in Alabama and Procedure for Prioritizing Hazardous Bicycle Routes

This study analyzes bicycle-vehicle crashes in Alabama to identify bicycle-vehicle crash causes/patterns. The analysis is based on 1,311 crashes in the state, representing five-year crashes (2011–2015). Detailed review of 1,311 police reports was performed and geometric/roadway variables were collected from Google Maps that were rarely explored in previous bicycle safety studies, such as: type of median on major road and crash location distance to upstream signalized intersection. This study adds to the literature by examining the effect of geometric/roadway features (e.g., presence of bicycle lanes, number of through lanes, and median type) on prioritizing bicycle routes while accounting for “bicycle mileage” exposure. Nighttime riding (19:01–7:00), and crashes involving males and middle-aged individuals (26–64) resulted in more severe bicycle-vehicle crashes. Compared to intersections, more severe crashes occurred at midblock sections at speeds higher than 35 mph. The chi-square test revealed significant correlation between crash severity and each of bicyclist safety equipment (i.e., helmets), intersection layout, and crash distance to upstream signalized intersection. The study also proposes a procedure for prioritizing hazardous bicycle routes while collecting bicycle exposure (bicycle mileage) using the City of Huntsville as a case study. Twenty-five bicycle routes (totaling around 170 mi) in the city were ranked by crash rate (i.e., crashes per mile) to identify hazardous routes. Bicycle routes on roadways with undivided medians had lower crash rates than those with divided medians. Bicycle routes having bicycle lanes on both sides of the roadway showed 50% lower crash rate than those on only one roadway side. Useful recommendations include: outreach programs emphasizing the importance of wearing reflective clothing at night and providing bicycle lanes on both roadway sides on designated bicycle routes.