Want to be hit by a car while riding a bicycle? Wear a helmet!

Normally, we wait for a paper to be released before covering new data, but this one intrigued me enough that I'm going to point out the press release to you. To get a greater sense of motorist-bicyclist interactions, a researcher named Dr. Ian Walker put his body on the line and went out on his bicycle, armed with a ultrasound distance meter. As both a cyclist and a frequent visitor to the narrow roads of my wife's native country, I admire his foolhardiness. Now, having been passed by motorists over 2,500 times and hit twice, he reached an inescapable conclusion: drivers passed closer to a cyclist that was wearing a helmet.

On average, a passing vehicle came about 8.5 cm (over three inches) closer to the researcher when he had a helmet on. Although it's easy to attribute this to an unconscious risk analysis—drivers view helmeted cyclists as less likely to suffer permanent damage if something goes wrong—other data suggested that it might have more to do with a driver's general sense of confidence. Professional drivers in delivery trucks and transit busses passed 19 cm and 23 cm closer to the cyclist, respectively. Our intrepid cycling researcher suggests that the presence of a helmet may contribute to the driver's confidence by signaling that it's being worn by a serious cyclist, one less likely to move erratically. An element of sexism may come into play as well, as wearing a wig designed to make him appear female was enough to gain an added 14 cm of space. If the other interpretations are right, it suggests that some drivers expect females to cycle a bit more erratically.

Regardless of the reason, Dr. Walker notes that the added risk to the cyclist may actually outweigh the benefits of the helmet: "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 judgements." A helmet may help with falls, but it's unlikely to do much good if the margin of error is eliminated by an overconfident bus driver. Oh, and those two collisions? He was wearing a helmet for both.