Free-Floating Bikeshare and Helmet Use in Seattle, WA.

Wearing a helmet when bicycling prevents traumatic brain injury in the event of a crash. Most cyclists nationwide use helmets when riding. However, the growth of free-floating bike sharing systems, which offer short-term access to bicycles but not helmets, may erode helmet-wearing norms among cyclists. We counted cyclists over several hours at four locations in Seattle, WA. We categorized each rider according to whether he or she was wearing a helmet and to whether or not he or she was riding a bike share bike. Whereas 91% of riders of private bikes wore helmets, only 20% of bike share riders wore helmets. Moreover, in locations where a greater proportion of riders were on bikes hare bikes, fewer riders of private bicycles wore helmets (r = - 0.96, p = 0.04). The impact of bike sharing programs on helmet wearing norms among private bike riders warrants further exploration.