Cyclists who ride without helmets are more likely to take risks while riding, like disobeying traffic controls or cycling while drunk, a new study of road accident data has found.

The study, conducted by academics at the University of NSW and published in the journal Accident Analysis and Prevention, examined NSW hospital and police records on 6745 cyclists involved in a motor vehicle collision between 2001 and 2009.

It found that wearing a helmet reduced the risk of head injury by up to 74%.

While 75.4% of the riders in the data set studied wore helmets, only about about half of those less than 19 years old wore helmets, the study found.

Non-helmeted cyclists were almost three times as likely to have disobeyed traffic controls as helmeted riders, and more than four times as likely to have been above the blood alcohol limit, said the study’s co-author, Dr Jake Olivier from the University of New South Wales’ School of Mathematics and Statistics.

“Those who wore helmets were more likely to be in high speed areas. If a person didn’t wear a helmet they were more likely to be in low speed areas. The overall effect was that helmet wearing was still beneficial,” he said, adding that the study showed wearing a helmet greatly reduced the risk of injury while riding.

“There have been calls from some people to get rid of helmet laws. What we have found disturbing is it’s young kids in the accidents not wearing helmets, kids who have their whole lives ahead of them and for whom having a serious brain injury will change their lives,” he said.

“People who don’t like helmets say it won’t help you with serious injury but this evidence points to the opposite.”

Professor Narelle Haworth, from QUT’s Centre for Accident Research and Road Safety - Queensland (CARRS-Q) said she was not surprised by the paper’s finding.

“This echoes a study we did that found that wearing a bicycle helmet was associated with a 69% reduction in the likelihood of head or brain injuries and a 74% reduction in the likelihood of severe brain injury,” said Professor Haworth, who was not involved in the UNSW study.

“Another observational study we did found that people not wearing helmets, or not wearing helmets that were fastened, were more likely to have conflict with pedestrians in the middle of the city.”

Dr Chris Rissel, Professor of Public Health at the University of Sydney said risky behaviour contributes to crashes.

“The authors say that bicyclists who do not wear helmets are more likely to engage in risky riding behaviours. Surely it is the risky behaviour that contributes to crashes, and hence injuries,” he said.

“A helmet won’t save you if you ride in a way that means you’re hit by a car.”

Dr Olivier, the co-author of the UNSW study, said it was important to remember that all cyclists studied in this piece of research had been hit by cars.

“The cyclists in this study are those who were hit by a motor vehicle in NSW between 2001-2009 who were hospitalised and/or reported the event to the police. All the estimates of increased risk/benefit proceed from that subset of the cycling population,” he said.

“Further, of cyclists hit by a vehicle, there was a demonstrable benefit for those who wore helmets versus those that did not. And those not wearing helmets were associated with illegal behaviour. All of these results already pertain to cyclists being hit by a motor vehicle and not all cyclists.”