Helmets may protect your head but mandatory helmet laws will likely make cyclists less safe
Some BC citizens are ramping up a campaign to get rid of the mandatory helmet law in British Columbia. Next year Vancouver will be launching a bikesharing system and this would be a good time to either get rid of the law or exempt bike-sharers. One of the only poorly performing bikesharing systems happens to be in mandatory-helmet haven Melbourne, Australia.
The anti-mandatory activists in BC may be making a very good point as economist Charles Komanoff explained on Streetsblog recently. Mandatory helmet laws are unlikely to make cycling any safer and could actually make things worse by turning people off from cycling (by as much as 20 to 40% in Australian states and cities!). The head protection that helmets give are then outweighed by the poorer health of those who decide not to cycle and a worse 'safety-in-numbers' effect for those still cycling.
Komanoff points out three key areas which helmet legislation proponents ignore:
- They ignore the possibility that some non-helmet wearers will cycle less or will refrain from taking up cycling in the first place rather than use a helmet or risk being cited for riding bareheaded.
- They ignore safety-in-numbers, or, in this case, its inverse, by which having fewer cyclists on the road tends to raise per-cyclist crash rates with motor vehicles, as cyclists’ diminished presence on the road leads drivers to treat them as aberrations rather than as part of traffic.
- They overstate helmets’ protective value in reducing injury severity in the event of crashes.
In the following two photos it's actually the father and daughter without helmets on Dutch separated lanes, and not the woman with the helmet and safety vest in the middle of Brussels traffic who are likely to be safer. Infrastructure and behavioural changes (such as in the Netherlands) have had a bigger impact on safety for cyclists then mandatory helmet legislation (such as in Australia).
Helmet legislation certainly has the intended effect of increasing helmet usage. But as Komanoff shows in his chart, it can be easily offset by the decrease in the safety-in-numbers effect. Part of the confusion in all this lies in the fact that proponents have assumed what is true in case-control studies is also true across a society. Case-control studies have suggested that cyclists who choose to wear helmets usually have fewer head injuries than non-wearers. The same is not true for a society where helmets have been made mandatory. Before and after data show enforced helmet laws discourage cycling but produce no obvious response in reducing the percentage of head injuries. Dr. Dorothy Robinson looked at all jurisdictions that had introduced legislation and increased use of helmets by at least 40 percentage points within a few months: New Zealand, Nova Scotia (Canada), and the Australian states of Victoria, New South Wales, South Australia, and Western Australia. When looking at head injuries he found that there was no clear evidence that the reduction in head injuries can be attributed to helmet laws. In all cases head injuries were dropping anyway. Robinson also found that in Australia cycling rates were increasing before helmet laws put the brakes to it.
The reasons helmet laws aren't working may be partly due to risk compensation where people feel that they can take greater risks when wearing a helmet; they might be wearing the helmet incorrectly. Some of the researchers also made incorrect adjustment for confounding variables in case-control studies where they misjudged how much of the effect was due to helmets.
Helmets also aren’t very effective in reducing injury damage to cyclists who are struck by cars, one of the main reasons to wear one in the first place.
The most authoritative epidemiological analysis of helmet efficacy to date, a study of 3,390 cyclist injuries reported from seven Seattle-area hospital emergency departments and two county medical examiners’ offices, summarized in Injury Prevention in 1997, found that helmet-wearing conferred only a 10 percent reduction in severe injury rates; and even this small differential fell below the threshold of statistical significance. What makes this analysis especially noteworthy is that it effectively invalidated the authors’ premature and incomplete conclusion in their decade-earlier study that helmets were spectacularly effective in reducing the chances of head and brain injuries; it was that “finding,” which has reverberated around the medical echo chamber ever since, that catapulted helmet promotion to the fore of bicycle “safety.”
And this isn't even taking into account the health benefits of cycling. A person who decides to avoid cycling is likely a person with an increased health risk due to inactivity and obesity. As Professor John Pucher points out:
“All scientific studies find that, even using conservative, understated estimates of the health benefits of cycling, they far exceed any traffic risk,” explains Pucher.
The exact ratio varies from city to city and from country to country, but the health benefits of cycling are at least five times higher than the traffic risks, and in some countries, such as the Netherlands and Denmark, the ratio is almost twenty-to-one.
So here's to having the choice of wearing a helmet or not. You can reduce the risk of a head injury for yourself by choosing to wear a helmet (though helmets are less effective when you're involved in a collision with a car). However let's not turn away people from a healthier lifestyle just because they don't want to wear a helmet. The risk of bad health is much higher for those who are sedentary than for those who cycle, helmet or no helmet.