Cyclists in Washington, D.C. who use Capital Bikeshare for their daily commutes are much less likely to wear helmets than commuters on their own bikes. That is the finding from an observational study conducted by Georgetown University School of Nursing & Health Studies (NHS) researchers that compares the rate of helmet use of casual and commuting Bikeshare riders with private cyclists. The research was published June 14 in the American Journal of Public Health.

Bike sharing is a popular option for transportation in the interest of personal fitness and environmental protection. Washington, D.C. is home to one of the largest bicycle sharing programs in the United States, Capital Bikeshare, and the concept has rapidly expanded to other cities, such as New York City and Chicago.

"Cycling is a healthy activity which both improves heart health and reduces air pollution, and we want to encourage it, but we also want to be sure riders are as protected as possible should they be in a crash," explains John Kraemer, JD, MPH, assistant professor of health systems administration at NHS and the study's lead author. "While Capital Bikeshare bicycles are designed to lower the risk of a crash occurring, with a lower center of gravity, heavier frame, lights, and reflective paint, helmets are essential for preventing serious injury in the event of a crash."

For the study, the researchers classified cyclists as likely commuters or casual users based on the time of day and location of their travel. The researchers observed commuters weekdays during rush hours and casual or tourist use in the afternoon on weekends in areas known as tourist destinations. They visually observed if all riders -- those using the marked Capital Bikeshare bicycles or riding a private bike -- were wearing a helmet. They also noted the riders' sex and approximate ages. These observations took place over the course of 30 days in the fall.

"The most surprising finding was the relatively low use of helmets among commuters using Bikeshare," Kramer adds. "We figured that casual users would be unlikely to wear helmets because many are tourists. But we thought that commuters -- people who plan their rides -- would be more likely to wear helmets than they appear to be."

The researchers concluded that out of the total 2,297 cyclists observed in the 30-day period (1,140 commuters and 887 casual riders), 10.1 percent of commuters and 12.4 percent of casual riders were Bikeshare users. Of those using Bikeshare, helmet use was significantly less compared to private cyclists. For example, 70.8 percent of commuters on private bicycles wore helmets, compared to only 33.1 percent of Bikeshare commuters.

Kraemer sees an opportunity for increased helmet use among commuters who are both likely to be more frequent riders and more susceptible to interventions with such efforts as targeted marketing messages or incentives. Capital Bikeshare already advocates helmet use on its website and at the time of membership sign-up, and it has launched pilot programs to distribute helmets through certain hotels.

Helmet use is the most important safety intervention for cyclists, Kraemer notes. "Bikers can't always control the environment around them, but they can control whether they wear a helmet. Helmets greatly reduce the risk of injury to both the brain and the face -- even if a cyclist is hit by a car."

Researchers say they plan to begin gathering information about reasons why riders, especially commuters, don't wear helmets.

Kraemer is also a part of the O'Neill Institute for National and Global Health Law at Georgetown University Law Center. Other authors on the study are Jason Roffenbender, MS, research associate with the Department of Human Science at NHS, and Laura Anderko, PhD, RN, who holds the Robert and Kathleen Scanlon Chair in Values Based Health Care at NHS.