Bike helmets - not wigs - save lives

British traffic psychologist Ian Walker is pedaling against other recent findings in suggesting that bicyclists who wear helmets are at greater accident risk. In fact, the day after Walker issued a press release about his study -- which said helmet-headed bicyclists are more likely to be struck by passing vehicles – four New York City agencies published a joint report that found that in almost all recorded bike fatalities in the city, riders were not wearing helmets. 

Walker, from the University of Bath, England, rode a bicycle fitted with a computer and an ultrasonic distance sensor to see how more than 2,500 passing motorists responded to him when he wore a helmet -- and when he did not. The results: “Drivers were as much as twice as likely to get particularly close to the bicycle when he was wearing the helmet.” Across the board, drivers passed an average 3.3 inches closer to Walker when he was wearing a helmet than when he wasn’t. What’s more, Walker was struck twice during the experiment -- once by a bus, another time by a truck -- and each time he was wearing a helmet.

Walker also donned a long wig, in order to gauge driver response to what appeared to be a female cyclist. And motorists gave him more passing room (5.5 more inches to be exact) when he wore the wig.

“This study shows that when drivers overtake a cyclist, the margin for error they leave is affected by the cyclist’s appearance,” Walker said in his press release. “By leaving the cyclist less room, drivers reduce the safety margin that cyclists need to deal with obstacles in the road, such as drain covers and potholes, as well as the margin for error in their own judgments.”

Walker theorized that drivers give helmeted cyclists less leeway because they believe the cyclists to be “more serious, experienced and predictable than those without.” However, he added, “in reality, there is no real reason to believe someone with a helmet is any more experienced than someone without.”

Randy Swart, director of the U.S.-based Bicycle Helmet Safety Institute (a nonprofit helmet advocacy group funded by consumers), said Walker may have a point about driver psychology. How a rider looks “does affect how close you’re going to pass. If you see an errant child riding in the road in front of you, swerving, you’re going to give that child extra room. If you see a competent cyclist moving straight along who seems steady, you might not give him extra room,” Swart said. But, he added, “the important thing to note was that cars were giving riders excellent clearance in all cases,” even when the cyclists were wearing helmets. The average car passed 4.4 feet away from the bicycle; the average truck, 3.8 feet away. As a result, that 3.3-inch difference “fades to insignificance,” Swart said.

Not insignificant, however, are the findings about helmet use in New York City’s recent survey of bike fatalities between 1996 and 2005. In cases where it was known whether the cyclist was wearing a helmet at the time of the crash, 97 percent of the fatalities occurred when the bicyclist was not wearing a helmet. Only 4 bicyclists who died (3 percent) were wearing a helmet. All child or teen bicyclists who died were not wearing helmets.

Given those statistics, Swart noted the trade-off for not wearing a helmet -- 3.3 more inches of the road -- may not be worth it.  In fact, properly fitting bike helmets can prevent 88 percent of bike-related brain injuries, according to one study.  Click here for complete Ratings of bike helmets recently tested by Consumer Reports, along with tips on getting the right fit from your helmet.

Comments

[Wendy Mastandrea]

"In fact, properly fitting bike helmets can prevent 88 percent of bike-related brain injuries, according to one study."

One study? Which one? Are there other studies about this and do they agree with this one? Because one study isn't enough to call the debate over. If you could provide the link to the study, I'd appreciate it. Thanks!

[Dr Dorothy L Robinson]

In view of your commendable aim to cut through hype and spin, I felt obliged to resond to Randy Swart’s comment: “the important thing to note was that cars were giving riders excellent clearance in all cases.”

Two drivers didn’t give excellent clearance – they gave no clearance at all, and actually hit Dr Walker.

Most drivers are considerate, but a small proportion takes too many risks. What’s important is not the average clearance (mentioned by Randy Swart), but whether risky drivers takes even more chances when overtaking helmeted cyclists.

Countries with low helmet wearing have more cyclists and much lower fatality rates per km cycled. A non-helmeted cyclist in Denmark or Holland is many times safer per cycle-km than a helmeted cyclist in the US. This pattern is also reflected in injury statistics. US cyclists with 38% helmet wearing suffer 30 times as many injuries per million cycle km as Dutch cyclists with 0.1% helmet wearing.

Dutch cyclists are safer because they ride on safer streets. But in the US, cyclists who choose to wear helmets are generally more safety conscious than those who don’t. Much of the claimed benefits of helmets may in fact be due to safer riding.

Several studies concluded that hormone replacement therapy (HRT) halved the risk of heart disease. But we now know that women who took HRT had less heart disease because of their healthier lifestyles, and that taking HRT actually increases the risk of heart disease. If studies of HRT (using the same methods as the bike helmet studies) produced incorrect results, the claimed benefits of helmets must also be questioned.

If helmets reduced brain injuries by 88%, there would have been an obvious response in the percentage of cyclists with head injuries in countries where helmet wearing increased by more than 40 percentage points because of enforced helmet laws. My systematic review (published in the BMJ) found little benefit from helmet laws, and probable harm from reduced cycling, reduced safety in numbers and risk compensation (see http://www.bmj.com/cgi/eletters/332/7543/722-a#154045)

Randy Swart’s efforts in improving helmet standards should be commended. But claims that helmets reduce brain injuries by 88% should be dismissed as hype. Risk-taking behavior (tripping, falling, bumping into things) increased by 50% when children running an obstacle course wore a helmet and wrist guards (http://dx.doi.org/10.1016/j.aap.2006.10.006). If the same is true for cycling, wearing a helmet will actually increase the risk of injury.