Do bicycle helmets put you at risk?
[Ian Walker] rigged his bicycle with an ultrasonic sensor that could detect how close each car was that passed him. Then he hit the roads, alternately riding with a helmet and without for two months, until he had been passed by 2,500 cars. Examining the data, he found that when he wore his helmet, motorists passed by 8.5 centimeters (3.35 inches) closer than when his head was bare. He had increased his risk of an accident by donning safety gear.
Why? You might suspect that cyclists wearing helmets are more prone to take risks. But studies have found otherwise. The real answer, Walker theorizes, is that helmets change the behavior of drivers. Motorists regard a helmet as a signal that the cyclist is experienced and thus can be approached with less caution. “They see the helmet and think, Oh, there's a serious, skilful person,” Walker says. “And you get hit.”
Now, depending on how big the differential is, the decreased mortality from helmets probably still makes them a good bet. But it's an interesting finding. Anecdotally speaking, the block-and-a-half I give obviously inexperienced, unhelmeted riders on their cell phones does make me less likely to hit them. On the other hand, my desire to hit them is certainly greater. Meanwhile, Walker rejects this interpretation, but a lot of good, often helmeted bikers act puzzlingly like little cars, darting into turns lanes and weaving through street traffic. That can't help your chances either.
