CYCLISTS who do not wear helmets are more likely to ride in ways that put them at risk, according to a study of more than 6700 bike riders who collided with motor vehicles.

The authors of the study say the evidence demonstrates the value of compulsory helmet laws, which some cyclists and researchers want repealed to try and increase the popularity of cycling.

Head first … helmets can minimise injury. Credit:iStock

Academics at the University of NSW's Transport and Road Safety Research Group and its School of Mathematics and Statistics looked at the relationship between the severity of cycling injuries on NSW roads and whether the bike rider was wearing a helmet.

The results, published on Monday in the journal Accident Analysis and Prevention, show that cyclists not wearing a helmet were almost four times as likely to sustain a head injury compared to those with head protection.