Helmeted riders more likely to be hit

By Tamara McLean, National Medical Writer

September 14, 2006 02:05pm

Article from: AAP
CYCLISTS who wear helmets for better protection on the road are ironically more at risk of being knocked down by cars, according to new research.

A study by a British traffic psychologist has found that drivers pass twice as close when overtaking cyclists wearing helmets than when overtaking their bare-headed counterparts.

Drivers shaved an average of 8.5cm off their passing distance when passing cyclists wearing helmets, increasing the risk of a collision.

"This study shows that when drivers overtake a cyclist, the margin for error they leave is affected by the cyclist's appearance," said Dr Ian Walker, from the University of Bath.

"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."

The scientist used a bicycle fitted with a computer and an ultrasonic distance sensor to record data from over 2500 overtaking motorists in Salisbury and Bristol.

Dr Walker spent half the time wearing a cycle helmet and half without and was knocked down twice, by a bus and a truck, while helmeted.

He said while helmets had been proven to protect kids in low speed falls, it was questionable whether they offered any real protection to somebody struck by a car.

"Either way, this study suggests wearing a helmet might make a collision more likely in the first place," Dr Walker said.

He believed drivers perceive cyclists as an unfamiliar sub-culture of "lycra-clad street-warriors".

Riders wearing helmets were incorrectly viewed as very experienced and less likely to do something unexpected, which explains why drivers leave less space when passing.

To test another theory, Dr Walker donned a long wig to test whether there was any difference in passing distances when drivers thought they were overtaking a female cyclist.

He said drivers gave "her" an average of 14cm more space than for a man not wearing a helmet, probably because women riders were seen as more unpredictable.

The study, accepted for publication in the journal, Accident Analysis & Prevention, also found that buses and trucks passed considerably closer than cars.