Amongst other things, the report considers the effectiveness of promoting or mandating helmet use for increasing safety. It finds:
Helmet usage reduces the severity of head injuries in cycle crashes but may lead to compensating behaviour that otherwise erodes safety gains.
Studies addressing the safety impact of helmets can generally be split into two groups: those that focus on the way in which bicycle helmets change the injury risk for individual cyclists in case of a crash and those that focus on the generalised safety effect of introducing measures (typically campaigns and/or legislation) to increase helmet usage among cyclists.
The first group generally finds that wearing a bicycle helmet reduces the risk of sustaining a head injury in a crash (head injuries are among the most severe outcomes of cycle crashes) though recent re-analysis of previous studies suggests that this effect is less than previously thought (Elvik, 2011).
To be clear — these studies indicate the possible reduced risk of head injury for a single cyclist in case of an accident. The effects must not be mistaken for the safety effects of mandatory helmet legislation or other measures to enhance helmet usage.
The safety effect of mandatory helmet legislation as such has been evaluated in far lesser studies than the individual risk in case of an accident. The safety effect of mandatory helmet legislation is a result of a series of factors:
- reduced injury risk (due to increased helmet usage)
- increased crash risk (due to an often claimed change in behaviour amongst cyclists who take up wearing helmet)
- less cycling (leading to a reduced number of accidents and injuries, but also to a higher accident risk for those who still cycle)
Whether bicyclists change their behaviour when they start to use a bicycle helmet seems very uncertain (and difficult to prove) but it is evident that mandatory helmet use might reduce the total number of bicyclists. It is also possible that cyclists who continue to bike might represent a behaviour which is different from the behaviour of those who stop biking. In the end this could very well lead to an overall change in behaviour.
Although the report makes 11 recommendations of ways for governments to improve safety for cyclists, there is no recommendation to make helmets compulsory.
The publication also presents a number of other interesting findings and recommendations:
- On balance, the positive health impacts of cycling far outweigh negative health impacts
- Cyclists should not be the only target of cycling safety policies – motorists are at least as important to target
- Cycling is safer on roads with bicycle specific infrastructure such as segregated lanes than on roads without
These are the sort of points that Australian governments should be basing our cycling policies around. Any measures, such as compulsory helmet laws, which reduce cycling numbers are likely to produce a net detrimental effect on the overall health of the community.
Efforts to reduce serious injury for cyclists must focus on the main source of the danger itself – namely collisions with motor vehicles. Mandatory helmet legislation does nothing to prevent these collisions occurring in the first place and the reduction in population-wide injury risk is non-existent or at best very small.
This is why the OECD forum has found there is no case to recommend compulsory helmets and as such it would be prudent for the few jurisdictions like Australia that do have these laws to repeal them.