Helmets or Not: Research Findings Turn Up the Heat

Englishman COLIN CLARKE was working in Australia when compulsory helmet laws were introduced. This prompted him to study the worldwide research on the subject, with some surprising results.

In Australia surveys into the effects of the compulsory wearing of helmets have found a 35% to 45% reduction in the number of cyclists, probably representing 3 to 4 million people. Fewer cyclists are suffering head injuries, but then there has been a decline in all road accident injuries, both in terms of fatalities and head injuries. In South Australia there were major reductions in the accident rates to motor cyclists and pedestrians, and in Victoria there has been a 33% fall in head injuries to pedestrians between 1989 and 1992. These improvements all follow major road safety programmes aiming at reducing speeding and drink driving. Following the introduction of speed cameras in Victoria, the proportion of motorists speeding fell from 23% in December 1989 to 4% in June 1993, resulting in a remarkable 50% drop in the State's road toll.

The incidence of fatalities and serious head injuries amongst cyclists is closely related to vehicular impact speeds. Janssen and Wiseman estimated that in vehicle-cyclist accidents, a drop in impact speed from 40 to 30 kph would reduce head impact acceleration by 50%. If braking distance and reaction times are considered, a reduction of driving speed of 4-5 kph may also have this affect.

The Victoria Injury Surveillance System (V.I.S.S.) has monitored accidents to child cyclists in Melbourne. The survey showed reductions in cycling of 36% and 45% for the first and second year of the helmet law. When a relative injury rate was calculated for the reduced number of child cyclists, the V.I.S.S. data showed that accidents increased by 13% and 21%, together with increased head injury of 6% in the second year.

The relative increase in accidents for cyclist who are helmeted is probably due to a combination of factors. One is risk compensation, where a better protected person becomes less cautious. Another is that cyclists can incur vibration and rapid accelerations to the head and helmet. Mathieson and Coin recorded accelerations of 100m/sec 2 when a cyclist hits a pothole at riding speed of between 15 and 25 kph. The effects which a helmet has on a cyclist's ability to balance makes him or her the least suited to all road-users for wearing a helmet.

Motorists will also take a less cautious approach if there are fewer cyclists to allow for. The Netherlands with a high cycle usage rate has an average of one cyclist fatality per 60 million cycling miles compared to Britain with an average of 20 million cycling miles per fatality (although clearly that's still an awful lot of miles!).

Moreover, laws requiring only cyclists to wear helmets are discriminatory in that the occupants of motor vehicles run about the same risk of a serious head injury per hour of travel as cyclists. Australia had 17 times as many vehicle occupants dying of head injuries as cyclists in 1988 but there are no requirements for vehicle occupants to wear helmets. Seat belts do not protect the head in roll over accidents where the roof may be flattened or offer much protection in side impacts.

Yet if aspects such as ventilation, storage space and effects on balance are considered, then it is more reasonable for vehicle occupants to don helmets than for cyclists. So not only do studies suggest that the wearing of helmets increases the likelihood of accidents and seriously discourage cycling, but helmet laws also infringe civil liberties by discrimination.

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