Bikeshare proponents often argue that one of the benefits of the systems is helping people exercise. But those healthy effects could easily be negated by severe head trauma.
That's because bikeshare users are far less likely than other cyclists to wear helmets when they ride, according to a new study from Georgetown University. For the study, researchers observed riders around Washington, D.C., and classified them as "commuters" or "casual" riders based on the times and locations at which they were observed. The study found that only 33.1 percent of bikeshare commuters wore helmets, compared to nearly 71 percent of commuters who used private bicycles. The divide was even bigger for casual riders: casual bikesharers wore helmets only 15.7 percent of the time, compared to over 68 percent for casual riders on other bikes. Altogether, bikesharers accounted for roughly 11 percent of all bikers observed--so while they may be a smaller population than the private-bike riders, the individual bikeshare users could be at a far greater risk of injury.
As larger cities like New York City and Chicago prepare for new bikesharing operations, the study raises questions about if—and how—bikeshare systems should promote helmet usage.
"Even though the bicycles used by Capital Bikeshare are designed to reduce the risk of crashes, the risk of injury is elevated for unhelmeted cyclists, should a crash occur," says the study. "This research suggests that bike sharing programs should invest effort in helmet promotion activities."
However, it's difficult to figure out how exactly cities would go about promoting helmets. One key question in that debate is whether helmets should be mandated.
In one sense, many bikesharing programs have already taken steps to prevent crashes by designing bikes that are built to be sturdy, not speedy. Capital Bikeshare, the system examined in the study, features stout-framed, bright-red bikes outfitted with fat tires and both front and rear lights.
"They have a very low center of gravity and really good lights," says John Kraemer, an assistant professor in the department of health systems administration at Georgetown University and one of the study's authors. He says that these features likely help bikers avoid wrecks.
"It's a heavy bike. It's not going to go very fast." says John Pucher, a professor in the Bloustein School of Planning and Public Policy at Rutgers University. "It's not going to be a really high speed trip, whereas if you're really on a racing bike, then the likelihood of a serious injury, a head injury, is going to be even greater."
In addition, instituting laws that mandate helmet usage may be impractical. The study notes that helmet laws might "impede the use of bicycle sharing programs."
That's because bikeshare systems are designed for convenience, and riders may not wish to carry a helmet all day for taking only one or two five-minute trips.
"The problem with requiring helmets with bikesharing systems is they're generally meant to be for very short trips," says Pucher. "Let's say you get off the subway or Metro, and you just need [a bike] to cover maybe, say, ten blocks. It's unlikely you're going to carry with you a helmet to use for that ten-block ride."
Alternatively, he says, bikesharing programs would have to take on the difficult task of figuring out how to dispense one-size-fits-all helmets at every station.
Short trips also generally make for less risk than longer trips. And while they may not do so for safety purposes, bikeshare systems encourage shorter trips within their pricing systems. Capital Bikeshare, for example, ramps up the price after 30 minutes of riding.
While there is an argument that helmet laws are unnecessary, Pucher points out that more riders on the roads, particularly when new bikeshare systems open for business (like New York's Citi Bike, which launches in July), naturally leads to greater risk.
"All of a sudden, you've got these 7,000 bikes, which anyone with a credit card can use. ... My guess is the people using those bikes are far less likely to be experienced cyclists," he says of New York's new system. "What I fear is you're going to have indeed a spiking--and it could be a doubling or a tripling--of injuries and fatalities, both of cyclists and pedestrians."
While the study may show that bikeshare users aren't wearing helmets, it doesn't probe riders' motives for not doing so. It may be due to convenience, as Pucher says, but one of the study's authors says that there may be parallels in other types of transit.
"There's interesting research that people who jump into taxis are less likely to wear a seat belt than if they're driving their own car," says Kraemer. Why that may be is itself a mystery, he says, but understanding why is on his docket. "That's the next step of what we're hoping to do."
Danielle Kurtzleben is a business and economics reporter for U.S. News & World Report. Connect with her on Twitter at @titonka or via E-mail at firstname.lastname@example.org.