The Latest Evidence That Helmet Laws Don't Help Bike Safety

Public health might be better off if cities focused on building better bike lanes instead.

Image Paul Krueger / Flickr
Paul Krueger / Flickr

It goes against all common sense, even as it’s become increasingly clear to anyone swayed by the science: bike helmet laws don’t seem to improve rider safety.

The latest evidence comes via a new study, published in BMJ Open, conducted by a group of Canada-based public health scholars. Kay Teschke of the University of British Columbia, in Vancouver, and collaborators gathered Canadian data on bicycle use, cycle-related hospitalization, and a number of other variables including helmet legislation in 11 jurisdictions between 2006 and 2011. Some areas had helmet laws over this period, while others did not.

Teschke and company found two factors to be statistically linked with bike hospitalizations. One was gender. For all types of injuries, women experienced “substantially lower” hospitalization rates than men did. This finding—in line with previous reports—could be the result of women being less likely to ride on major city streets that don’t have separated bike lanes. Another possible explanation offered in the past is that women tend to ride slower than men do.

The second main variable related to bike hospitalizations was local cycling mode share. For traffic-related injuries in particular, areas with higher shares of bike riders among all travelers had lower hospitalization rates than other regions, a finding that held for all bodily injuries as well as those to the head or brain. In other words, when more people ride bikes, fewer riders get injured—a clear sign that cyclists experience safety in numbers.

What the researchers failed to find was any connection between helmet laws and bike-related hospitalization rates. That held true whether they looked at all cycling injuries or just traffic-specific injuries. Surprisingly, it also held true when they narrowed in on body parts protected by a helmet: the brain, head, scalp, skull, face, even neck. Since helmet laws don’t necessarily mean compliance, they looked at helmet usage, too, and once again found nothing.

The point is not that helmets do nothing or that you shouldn’t wear them. If you fall off your bike and hit your head, it’s obviously much better to have a helmet on. At a personal level, if that’s what it takes to get you riding, by all means, helmet up. But at the local government level, it’s time to recognize that other safety measures have far greater public health benefits—in particular, well-designed infrastructure that separates riders from general traffic.

Here’s Teschke, writing to CityLab via email, on how there’s sufficient evidence out there by now “to shift our focus” from bike laws to bike lanes:

It has dual advantages, both reducing injuries and encouraging cycling, an important public health goal of its own given the physical activity and environmental benefits. Comparisons between North America and the Netherlands or Denmark have long suggested that their route design focus is better at welcoming cycling and achieving lower injury rates. Many were concerned that Dutch and Danish infrastructure wouldn't have the same impact here, but there is more and more research in North America showing that it does.

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