Another salvo in the helmet wars

December 11, 2018 § 10 Comments

It would be so nice if we could say that wearing helmets is always better than not wearing them, and the great news is that if you live in the South Bay, where people love to shout “WHERE’S YOUR HELMET???”, you can certainly live out your cycling life believing that the little styrofoam and plastic doohickey atop your skull is making you live longer, safer, healthier, more happily, and without having to consider facts, science, competing ideas, or, dog forbid, studies.

Two doozies recently popped up on my radar screen thanks to friends who, like me, wear helmets, just not all the time, and who, like me, find it amusing that so many cyclists screech and wail about helmets as if they were the panacea to everything from head injuries to herpes.

The first study was a confirmation of an earlier study which found that cagers are more likely to subject riders to dangerous punishment passes when the riders are helmeted. This means that in many situations wearing a helmet actually encourages motorists to endanger you, and of course some of those punishment passes result in collisions.

To repeat: In some instances, helmets INCREASE your risk of injury or death. Here’s the study, so fascinating as it shows how a dedicated researcher spent five years validating his results after they were attacked by helmet nazis, and it shows how truly disturbed and careless many motorists really are. Passing someone closer because they wear a helmet?


Hold on there just one darn minute!

Before the anti-helmet forces burn down all helmet factories and declare victory, another study popped up that sort of debunks the risk compensation hypothesis, which states that cyclists with helmets engage in riskier behavior than those without.

Anyone accustomed to wearing a helmet knows that when you take off your lid you feel more exposed and try to be more careful, at least for the first few minutes until you are overwhelmed with the joyful free feeling of the wind in your hair, but this doesn’t necessarily mean that once you strap on the helmet you become a kamikaze.

You can read the abstract here; it’s kind of a plus for helmets unless you are unlucky to run the thing by America’s best bike analyst, John Forester. John basically says all of the studies are crap because of one tiny little detail: None of the studies can define risky behavior; safe cycling isn’t as cut/dry as safe sex. Here’s his analysis:

I have read the summaries presented in the article listed below. The question is whether or not the wearing of a cycling helmet induces more risky behavior. It is believed that this is a question that is worthy of consideration. In some kind of theoretical consideration of the science of psychology this issue may be worthy of consideration, but in this specific and practical case consideration is completely worthless. Why? Because nobody knows which cycling behaviors are safe and which are risky. Consider whether obeying the traffic laws is, or is not, risky. There is plenty of evidence that many Americans believe that cyclists obeying the traffic laws are riding in a very dangerous manner, whereas obeying the traffic laws is the key to safe operation.But which traffic laws? Those which make vehicle operation safe, or those intended to restrict cyclists for the convenience of motorists under the excuse of cyclist safety? The article repeatedly referenced the relationship between fear of danger and risk aversion. However, it is well known that those who most fear traffic dangers are also those who ride in the most dangerous style, curb hugging. Dutch-style slow and helmetless cycling seems to be safe, while faster cyclists seem more likely to use helmets. Does that mean that fast cycling is a risky behavior? To some extent it does. The faster the cyclist in a crash, the more likely is he to be carried forward (by his own momentum) and therefore the more likely he is to land on or near his head. So it is reasonable that faster cyclists tend to wear helmets. But does that mean that fast cycling is risky behavior? Or only that slow cycling is inconveniently slow? As long as opinions about cycling risk are in such contradictory confusions, any attempt to analyze cyclists’ habits in terms of risk homeostasis is bound to fail.

John Forester, 2018

Of course anyone who can use the words “risk homeostasis” in a sentence wins the Internet for the day, so those who would force everyone everywhere to always helmet up … try again.




§ 10 Responses to Another salvo in the helmet wars

  • zigak says:

    I wear a helment because it makes me look 20 years younger*. Hope someday it will be socially acceptable to keep it on even after the ride. You’re not helping.

    *My bald spot is expanding like an ozone hole in the nineties.

  • drbeachbum says:


    Allow me lodge my complaints about the research you assert supports your style of riding without a helmet: the Walker 2007 study.

    1. The Walker 2007 study had a sample size of one. Although this doesn’t change the statistical significance of the results, as the author points out, it does change the results “generalizability.” This an important component to any scientific study and roughly means: to whom do these results apply? In the case of the Walker 2007 experiment I argue that you cannot say those result apply to Seth Davidson or anyone else in the South Bay. Why? Here are the a few uncontrolled variables in the study: motorist geographical location, cyclist apparel, cyclist equipment, cyclist speed, cyclist group size, cyclist riding style, cyclist age, cyclist gender. An alteration of any one of these variables may completely change the results. That makes the results highly ungeneralizable, and not appropriate for you to cite as a reason you or others shouldn’t wear helmets.
    2. The Walker 2007 study showed the change in motorist distance to be 8.5cm closer to the subject when wearing a helmet. Although that distance may be statistically significant within the sampling, it has not been shown that 8.5 cm closer means more dangerous passing. I cannot access the results and data analysis sections of the publication to confirm the mean passing distances and I presume, perhaps erringly, that you cannot either. Therefore, you cannot conclude that the closer passes in the helmeted condition were any MORE dangerous than than the passes in non-helmeted condition. In fact, this is crux of the “new” study you cite for this blog. It’s not really new, it’s just Walker’s rebuttal to the Olivier and Walter’s 2013 study that refuted Walker’s original 2007 study. Olivier and Walter objected to Walker’s definition of “close pass” and re-analyzed the data using industry standard 1m passing to differentiate “close” versus “not close” passes. With this definition there was no statistical increase in “close” passes in helmeted versus non-helmeted conditions.
    3. But the new study cited, so far as I can tell from the Forbes review, does not refute the Olivier and Walter paper, which refutes the notion that wearing a helmet is dangerous because it makes cars pass you dangerously, it simply shifts the argument to: let’s make this an issue about reducing motorist/cyclist collisions. That’s an entirely different issue, worthy of investigation. However, you may not like this study’s recommendations: separate cyclists and motorists.

    Which brings us to another helmet objection offered by the authors and yourself: helmets are trivial protection in some bike/car collisions. This idea is further echoed by the author of the Forbes article, Carlton Reid, when he asserts, “Helmets do not protect against concussion.” This is false. Helmets do indeed protect against concussion by reducing the severity of such injuries, especially reducing the chance of skull fractures. I believe what the author meant was, helmets do not “prevent” concussions. Which is fine, because that isn’t their function. Helmets are only designed to reduce the severity of concussion and mitigate against skull fracture. They are like bullet proof vests, they don’t eliminate injury, they don’t prevent all injuries, they simple make most injuries less severe. Is that important? As a published researcher in the area of traumatic brain injury (go ahead and google my work with Robert Sbordone and Ronald Ruff), I assure you that the severity of concussion is extremely important, with more severe concussions correlating strongly with more severe immediate and long term brain damage. Furthermore, skull fracture head injuries are associated with even poorer outcomes than severe closed-head injuries. The flimsy piece of styrofoam on your head is absolutely lowering your risk of skull fracture when you hit the ground even if, like the bullet proof vest, it cannot mitigate against all injuries.

    Sure, we can argue about the best measures to take to reduce cyclist’s chance of injury, especially concerning motorist/cyclist related injuries, but meanwhile you should probably put on the thing that greatly reduces the severity of any injury, should it occur, just like a cop wearing her “bullet proof” vest while on duty.

  • Tamar T. says:

    I do wear a helmet (me=wimp) but I draw the line at the marketing bullshit that is MIPS. So I have learned not to say anything when I see someone helmetless, but I happily vent when I see a friend “upgrade” their perfectly good helmet with a “safer” heavier and more expensive helmet with MIPS. I found this gem today.

  • Linda says:

    Riding without a helmet is just another instance of choosing what you do with your own body. What does it really mean to be “pro choice”?

  • Vlad Luskin says:

    Has anyone controlled close passes helmet studies for clothing in addition to helmets? Hypothesis: cagers pass lycra wearers closer than they pass street clothes wearing cyclists. Lycra wearers are more likely to wear helmets than street clothes wearing commuters. If confirmed, further proof that cagers dislike recreationists more than commuters.

  • pvannuys says:

    What John is saying is there really is no factual conclusion to be drawn re helmet use. Those of us who ride “fast” seem pretty unanimous in habitual helmet wearing, but that doesn’t really make for valid endorsement. Here’s my advice, for life as well as riding:
    “Strive at all times to remain upright.”

  • My hat collection includes: a white bike helmet, which I wear with spandex on the fast bike. Make me feel that I can go faster. I wear a baseball cap on the everyday around town bike. And a hard hat in the truck for work on construction sites.

    If only there was another option to a real helmet for bicycle riders. Maybe something like a pretend helmet like many motorcyclists wear to avoid actually wearing a real helmet? It would be made of very lightweight plastic shell and some Styrofoam. Could protect against minor falls, but nothing for a major collision. Yeah that’s it!

    And kudos for quoting John Forester.

  • Looking at Walker’s study, did he have anyone else where a camera and provide data? Once test subject seems an awfully thin data set to base conclusions on, however, those conclusions may actually be fairly universal and not limited to cagers in his locale.

    Personally, I guess I always thought helmets to be more of a “If something happens, and you are going to the ground, wouldn’t it be better to have one on, rather than not?” Even in the slowest falling off bike incidents, my helmet hit the pavement hard enough to crack the helmet.

    I can’t even off statistics that say, I have gone down more riding with others, or because of others. I have seen people crash because of other cyclists, or because they overlapped wheels etc, but my own falling off incidents have been self inflicted mechanically induced failures. Hardly conclusive.

    I think I am with you though. If you want to ride solo down to the coffee shop or elsewhere, why should you have to wear a helmet, and why do other adults have to treat you like you are a child?

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