A Major Study Finally Settles The Debate On Bike Helmets–Or Does It?

Bike helmets drastically reduce risk of dying of a head injury–but whether riders should be required to wear one is still murky.

A Major Study Finally Settles The Debate On Bike Helmets–Or Does It?
[Photo: Flickr user Sigfrid Lundberg]

Eventually, every discussion about cycling in a city will devolve to two points: cyclists deserve everything they get, because they don’t respect the rules of the road–and bike helmets.


The pro-helmet folks say that helmets could stop you getting brain damaged and that motorcyclists have to wear helmets, and you wouldn’t argue against that now, would you? The “anti”-helmet folks (or, if you prefer a less loaded term, “pro-choice”) say that cycling just isn’t that dangerous, and if you make helmets compulsory, you’ll dissuade many people from riding a bike and enjoying the health benefits it brings.

[Photo: Photo: Flickr user knehcsg]

Into this crucible of opinion comes a new meta-study that assesses a bike helmet’s role in preventing serious or fatal head, face, and neck injuries. Forty studies were included, covering over 64,000 injured cyclists. The result? Bike helmets do indeed reduce the odds of injury.

It’d be tricky to find anyone who doesn’t think that helmets reduce head and brain injury in the unlikely event of a crash or fall, and the results of this paper agree.

Helmet use is associated with odds reductions of 51% for head injury, 69% for serious head injury, 33% for face injury and 65% for fatal head injury.

Further, wearing a helmet doesn’t appear to increase the likelihood of neck or face injury, as some helmet-skeptics fear. More interesting, though, is what the researchers, from the University of New South Wales, Sydney, Australia, found out about other topics along the way.

For instance, mandatory helmet laws don’t appear to make much difference, safety-wise. Because this meta-study only looked at studies of head injuries, it has no date on whether mandatory helmet laws actually deter cyclists from getting on a bike, but it does have enough data to say that safety is neither improved nor made worse. The conclusion on this subject is similarly noncommittal. “The results of this review do not support arguments against helmet legislation from an injury prevention perspective,” says the report.

Risk compensation is another helmet-related controversy. The theory says that cyclists subconsciously take more risks when they wear a helmet, because they feel safer. They may ride faster, or closer to other vehicles. Another related issue is that of drivers treating helmeted cyclists more cavalierly, possibly for similar reasons.


This is notoriously hard to test, and as none of the reviewed studies included data on risk compensation, they were no help. But the authors do cite a pair of recent, large studies on risk compensation. The results? Useless. After adjusting for all many other factors, the difference in risk level between those with helmets and those without was all but indistinguishable.

Overall, then, we still don’t have much extra ammo to deploy in our helmet arguments, whichever side of the debate we’re on. We know that if you do crash, then wearing a helmet could save your life, or at least stop you ending up with brain damage. But that means nothing if you don’t crash, if you do crash but don’t land on your head, or if you avoid cycling because you weren’t allowed to do it without a helmet.

Perhaps a better argument is that helmets mightn’t be necessary at all if we didn’t force cyclists to use the same roads as cars, trucks, and buses, or if we prosecuted drivers who drive too close to cyclists. The safer it is to ride, the more people will do it, and the fewer cars we’ll need. There’s probably somebody out there who would argue with that, but they’d be wrong.

Have something to say about this article? You can email us and let us know. If it’s interesting and thoughtful, we may publish your response.

About the author

Previously found writing at, Cult of Mac and Straight No filter.