May 14, 2007 A British scientist has proved that wearing a bicycle helmet actually exposes cyclists to further risk. Overtaking traffic passed helmeted cyclists with significantly less room than unhelmeted cyclists - and the bigger the vehicle, the closer the average passing distance was. As civilised as we pretend to be elsewhere, we consistently act like might is right on our roads.
Road psychology is fascinating. Driving really seems to bring out the animal in us; put an otherwise considerate and socially adapted person in a metal cage and stick them into peak hour traffic and you'll see them shout, swear and punish other road users in ways they'd never dream of in a social situation. It's mankind at its prmitive worst; the thinnest point in our fragile veneer of civilisation, where the law of the jungle underpins our actions and social conventions go out the window.
Size is everything; trucks intimidate 4WDs, who muscle out compact cars. Commuting motorcyclists learn quickly to be hyper-vigilant around anything with 4 wheels - but even their lot can't compare to the vulnerability of bicycle riders, who travel much slower than the speed limit, are able to own very little road space, and typically wear only the bare minimum of protective gear.
Riding a bicycle in peak-hour traffic is at best harrowing, and at worst downright treacherous. While cyclists are able to feel in some control over what's happening in front of them, car drivers in the outermost lane tend to see them as an annoying chicane and overtake leaving a fraction of the space they'd give another car. And research from the University of Bath shows that where a cyclist is wearing protective clothing, drivers are likely to cut in even closer.
Dr Ian Walker, a traffic psychologist from the University of Bath, used a bicycle fitted with a computer and an ultrasonic distance sensor to record data from over 2,500 overtaking motorists in Salisbury and Bristol last September.
Dr Walker, who was struck by both a bus and a truck in the course of the experiment, spent half the time wearing a cycle helmet and half the time bare-headed. He was wearing the helmet both times he was struck. He found that 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 of 8.5 cm (3 1/3 inches) closer with the helmet than without. The research has been accepted for publication in the journal Accident Analysis & Prevention.
Size of vehicle also played a role: the average car passed 1.33 metres away from the bicycle, the average white van was 10cm closer. The average truck was a further 9cm closer, and the average bus 4cm closer again - 23cm closer on average than a car.
Furthermore, Dr. Walker wore a long wig on some trials to see if perceived gender had any effect on overtaking distances. It certainly did - drivers gave him an average 14cm more room.
What are the implications? Perhaps when drivers see male riders suited up with all the correct gear they assume they'll be more predictable and able to get themselves out of trouble. Maybe there's some sort of chivalrous courtesy going on when female riders are left wider gaps. Perhaps, as the vehicle size data suggests, drivers simply see overtaking a cyclist as an opportunity to stamp their road authority on a weaker, more vulnerable competitor for tarmac space.
Either way, the research throws a very interesting slant on the mandatory bicycle helmet laws found in many areas. While helmets are clearly an advantage in a fall, there's little to suggest they do much when the rider is hit by a car or truck. And if a helmeted cyclist experiences around 20% more close overtaking moves than his unhelmeted contemporary, does wearing a helmet actually make bicycle commuting more dangerous?
A fascinating psychological study. Want to see a person's true character? Study them alone, in a car, in traffic. And prepare to be shocked.