To Wear Or Not to Wear (and Is That Even the Right Question?): Ian Walker on Cycle Helmets

When I was in the U.K. doing radio interviews for Traffic, I would often get asked if wearing cycle helmets actually made things less safe for cyclists. This happened primarily because the book features rather striking research by Ian Walker, a traffic psychologist at the University of Bath, and this was mentioned in the press kit.

To briefly summarize, in his study (published as “Drivers overtaking bicyclists: Objective data on the effects of riding position, helmet use, vehicle type and apparent gender,” in the journal Accident Analysis and Prevention), Walker outfitted a bike with a device that measured the distance of passing cars. He found, among other things, that drivers tended to pass more closely when he was wearing a helmet than when not (he was struck by vehicles twice, both while wearing a helmet).

This was a surprising, somewhat controversial finding that generated a lot of news coverage. To my mind, Walker’s findings were more interesting for what they said about interpersonal psychology on the road than safety itself; mostly because I felt, and Walker seems to agree, that the primary question of bicycle safety had less to do with the helmet than other factors. As the above photo suggests, cyclists in places like Copenhagen or Amsterdam very rarely wear helmets, and yet they enjoy a much safer ride than in places (like the U.S.) where helmet-wearing seems more ingrained. The argument is often made that those places have protected cycle lanes and the like — though the photo also shows that is not always the case.

But to return to the radio interviews, I often found myself getting frustrated because the radio journalists seemed to want a handy “takeaway” answer: Well, do helmets make cyclists safer or not? The problem was, I really didn’t know (disclaimer: I do wear one, rather out of habit and without much thought other than a fear of New York City streets).

This was a problem I had in trying to give many answers relating to traffic — there are often an endless series of “on the other hand” qualifiers. As with any kind of epidemiological inquiry, traffic presents such a complex system, with so many interacting variables (e.g., do helmets make drivers act less safe) and “confounding factors” and incomplete data sets, that coming up with easy answers is impossible: and anyone who seems to have easy answers probably doesn’t know what they’re talking about. One favorite example of this for me is the nutmeg you hear drivers say, with deeply held conviction: ‘Well I’ve heard it’s not speed itself that’s the problem, it’s differences in speed.’ This is a statement that is true — except when it isn’t. It lacks context, it lacks explanatory power. We would do as well, if not better, to note that every traffic fatality/injury involves speed: If the car wasn’t moving, no one would have died/been injured.

But I was curious as to how Ian Walker, after putting his research into the world and subsequently being asked these sorts of questions, undergoing these sorts of debates, ultimately felt himself about what his findings (at least on several stretches on English roads) had revealed.

Over to you, Dr. Walker:

“The apparently simple query ‘Do bicycle helmets work?’ turns out to be the most complex question I have ever encountered. Since I published my own small contribution to the nightmarish tangle of helmet research a couple of years ago, I have read and answered hundreds of emails on the subject from interested – in both senses of the word – people. I am grateful to Tom for giving me this chance to summarize a few of my disjointed thoughts on the matter.

First, let me deal with this matter of interest: I have none. I do not make bicycle helmets, nor do I sell them, and nor do I have anything to gain from their demise. It really doesn’t matter to me one way or the other if they ‘work’. I am a scientist, and what interests me is getting at the truth, whatever that is. This leads me straight onto the big issue: I do not know whether or not bicycle helmets save lives. And, critically, nor does anybody else.

The reason nobody knows for certain is that only one method exists for us to get a definitive answer: the experiment. If we took a large number of bicyclists and randomly made one-third ride with helmets, one-third ride with fake helmets (the placebo) and one-third ride with no helmets (the control), then after a couple of years we could count the dead and get the answer we are hoping for. Sadly, however, there are some fairly obvious ethical difficulties with this plan!

So all the evidence we will ever have on this matter is indirect: casualty figures, surveys and observational studies, all of which are riddled with biases. And for every piece of evidence we can find in one direction, there is another telling us the opposite. Let me outline just a few of the many reasons why the topic is so complex.

First, I am not going to deny that putting some padding on your head will absorb some energy in an impact. It would be crazy to suggest otherwise. The actual amount of energy absorbed is almost certainly smaller than you think, but the fact is there has to be some cushioning: if a particularly weird kidnapper made it clear I had absolutely no alternative but to be hit on the head with a hammer, I would definitely choose to wear a bicycle helmet rather than go bareheaded. This all leads us to the ‘common sense’ position which at one extreme says ‘obviously’ helmets are useful and which, at its most conservative, would say it ‘cannot hurt’ to wear a helmet.

The difficulty with this position is twofold. First, even if a helmet absorbs a lot of energy in an impact, this benefit might be cancelled out by the helmet making the impact more likely in the first place. If you have read Tom’s excellent book, you will be familiar with the idea that people might adapt their behaviour to take more risks whenever they start to feel safer. We have no hard evidence on this, but it is plausible, given what we have seen elsewhere in traffic, that helmets make riders feel safer and they respond to this by taking more chances. And even if the riders don’t change their behaviour, my research showed the drivers with whom they share the road certainly change theirs: whenever I put a helmet on, other things being equal, drivers got measurably closer as they passed my bicycle. This will almost certainly translate into a higher likelihood of accidents across large numbers of people.

The second issue with the ‘common sense’ position is this: if helmets do work, why is this proving so difficult to see? In countries where helmets have been made mandatory, and where usage went from low to high levels almost overnight, there is just no real evidence of a concomitant drop in injuries. Indeed, what we see instead is a big drop in the number of people cycling, which is a disaster – far worse for public health than the few head injuries the helmet laws tried to prevent. Whenever a person gives up cycling, they get far less day-to-day exercise. This means they trade a very small risk of dying from a head injury (almost certainly smaller than you think – I can almost guarantee it won’t be a bicycling head injury that sees you off) for a greatly increased risk of dying early from heart disease or cancer (almost certainly larger than you think – I’d lay good odds that one of these two will get you).

Matters are further complicated in other ways. It is possible to find evidence from hospital records suggesting bicyclists who wear helmets hurt themselves less often. But it is equally possible to find evidence that bicyclists who wear helmets ride more cautiously, and are much less likely to mix with motorized traffic – which is where most of the danger comes from in the first place.

These have just been the headlines. There are any number of other complexities which further muddy these waters, but I won’t go into them for fear of taking over Tom’s whole blog. Instead, I will exploit his generosity another way, by using this platform to get something off my chest. Here are two comments I have heard – quite seriously – dozens of times. They are comments which, as an evidenced-based researcher, I would be happy never to hear again:

1. “I crashed my bike and afterwards the helmet had shattered into several pieces. This proves it saved my life.” It is the illogic that riles me here. If you don’t see the problem, replace the word ‘helmet’ with ‘egg’. Just because the helmet was broken after a crash, this tells us very little. I know what people mean to say, of course – they are trying to say ‘the helmet must have taken the blow’, but this pre-supposes too much about how well helmets are able to do this. Plus, as many motorcycle helmet engineers will tell you: if it cracks, it’s failed.

2. “After the crash, all the paramedics, doctors and nurses told me the helmet had saved my life.” Did they? Did they really? I do hope not, because what evidence did they base that statement on? Did they make the hapless bicyclist crash again in exactly the same circumstances, this time sans helmet, to confirm they would die bareheaded? Bah! The medical profession is seen by most laypeople as the paragon of science, but in reality it has its fair share of prejudices and orthodoxy. One of these is the fixed belief, de-spite the complexity of the evidence, that wearing a helmet must be a good thing. I really would like to believe the following tale, which someone once related to me, is genuine. A bicyclist visited their doctor with a damaged knee following a crash. “You should have been wearing a helmet,” says the doctor sternly. “How would that have saved my knee?” replies the cyclist.

So to sum up, nobody knows for certain whether bicycle helmets work, overall, to protect bicyclists. They must absorb some amount of energy in a collision, and although I’m not sure how much of the energy they touch from a 2-ton car, even if they removed a lot of it, there are plausible ways in which that benefit gets cancelled out by helmets making accidents more likely in the first place. Most bicyclists who die with head injuries also have fatal chest injuries too.

I’d always recommend helmets for children, whose accidents are slow-speed falls in the absence of traffic. But for adults, who travel at higher speeds, often in the presence of motor vehicles, we will never have a 100% reliable answer about whether they decrease or increase risk. In the interests of full disclosure, I very rarely wear a helmet myself. What you do is your own decision. Just make that decision is based on your reading of the evidence rather than guesswork, that’s all I’m asking.

And finally, having said all that, I would like to suggest that this is all the wrong question to be asking anyway. Nearly all of the serious danger to bicyclists comes from drivers. Instead of fretting about the utility of helmets after collisions happen, bicyclists should be focusing on the careless or reckless driving that causes those collisions in the first place. Consider burglary for a moment: I would suggest the prime responsibility for this social ill lies with the burglars who choose to perpetrate it rather than the householders who are the victims. I can’t help feeling bicyclists are in a very similar position when they allow themselves (ourselves!) to get drawn into this debate.”

Ian Walker

This entry was posted on Wednesday, October 1st, 2008 at 4:01 pm and is filed under Bicycles, Cyclists, Risk, Roads, Traffic Culture, Traffic Psychology. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

30 Responses to “To Wear Or Not to Wear (and Is That Even the Right Question?): Ian Walker on Cycle Helmets”

  1. Joseph Logan Says:

    Hmmm… My observation from living in Holland, working in Sweden, and biking recreationally in the US is that casual, transport-oriented bikers seem never to wear helmets in the European countries and have few accidents (a recent exception was a biker in The Hague being struck and killed by a tram, but he was American and the helmet probably couldn’t mitigate the effects of being struck by a tram). Recreational bikers (mountain bikers and competitive road cyclists) in the US and in the European do wear helmets, perhaps due to anticipated speed or obstacles. I love bicycles and hang out with cyclists as well as biking to work, and in neither case have I observed enough accidents to make any kind of generalization about helmets. Experience suggests that Dr. Walker’s observation about the danger of cars rings true. Unlike Walker’s study, N=1 in my case, but the results feel about right.

  2. ScottF Says:

    I’d just like to point out that even if a cyclist is more likely to be hit by a car if wearing a helmet, in the case he was hit, he would also be more likely to survive.

  3. Joe Says:

    I’d just like to point out that even if a cyclist is less likely to be hit by a car if not wearing a helmet, in the case he wasn’t hit, he would definately survive.

  4. sasha Says:

    There was a 12 year study done up here in Toronto at the Hospital for Sick Children. Over the course of the study there was an average drop of over 50% in deaths when the helmet law for children under the age of 16 was passed in 1995.

    See more in the globe and mail article:

  5. Mark Says:

    Those are very small numbers (which implies that the risk of cycling is much lower than risks we don’t generally think are worth protecting against), and, more importantly, there’s no mention of injury *rates*, and no mention of helmet-wearing rates over the entire period.

    For a critical view of the Toronto experience, take a look at, for instance

    and look at the rest of the site, while you’re at it. What strikes me about the helmet question is firstly that the risk to cyclists is evidently *very* low, and secondly that population statistics invariably show no substantial benefit, or disbenefit, to wearing a helmet; like it or not, it may go against common sense, but it does seem to be the case.

  6. Shek Says:

    I dont wear a helmet on my 2 mile commute to work. I also commute in business clothes on a dutch bike. I have noticed that I get harassed a lot less, almost none riding this way than when I rode my mountain bike to work.
    Having said that, I do ride 10 miles to a library for a meeting once a month and the commute takes me through high strip-mall concentrations on 6 lane roads (45 mph speed limits). I do wear a helmet there so I can leverage any little benefit in the event of an accident. It makes me feel safer.

  7. David Hembrow Says:

    You can turn this argument around:

    Helmets are worn due to a lack of subjective safety. Where people feel safe to ride their bikes, few or perhaps none will wear helmets. Where they feel unsafe, many will wear helmets.

    You will also find that where subjective safety is high, more people find cycling to be “safe enough” that they take part.

    That explains the difference between the low rate of helmet wearing, but high rate of cycling that you find in the Netherlands and the high rate of helmet wearing and low rate of cycling that you find in English speaking countries.

    I’ve written this all up before:

  8. Mikael Says:

    What a great post.

    That Toronto study forgot to mention that cycling dropped between 18-27%. Fewer cyclists, fewer injuries.

    What is interesting in the bicycle helmet debate is that besides the helmet manufacturers financing lobby groups for obvious reasons, there are many automotive groups that advocate helmet laws. The biggest is FIA – and they are very noisy about helmets.

    Why? It removes focus from dangerous drivers and, if a motorists hits an unhelmeted cyclist in a region where helmets are required by law, the cyclist is liable. There have been so many case in the UK where motorists have sued injured cyclists because they weren’t wearing a helmet. No judge has ever ruled in favour of the helmet, despite all the experts saying their bit.

    In addition, the automobile orgs don’t want to see laws popping up like those in Denmark and Holland, which place blame on the motorists in any situation where ‘soft traffic’ is involved – pedestrians or cyclists. The ‘hard traffic’ is always to blame because of the responsibility of driving around in motor vehicles, even if a pedestrian jaywalks or whatever.

    While I am an active advocate against helmet promotion and legislation who has done his homework, I have this constant nagging feeling that bike helmets are the greatest scam in the history of sports equipment.

    Anyway, a recent post on my blog discusses The Culture of Fear regarding bike helmet promotion in Denmark.’

  9. Jim Tubman Says:

    I took the time (and expense) to download the Pediatrics paper referred to in the comment by Sasha. A number of questions could be raised about it.

    Probably the most crucial one is the paper’s claim that the law was enforced beginning October 1, 1995. My understanding is that the law has never actually been enforced; apparently not a single ticket has ever been issued to a helmetless child cyclist in Ontario.

    The paper is also evasive about the relationship between the reduction in fatalities and changes in level of exposure. They cite a paper that describes an observational study in a Toronto neighbourhood, ending in 1997 (whereas the Sick Children study carries on to 2002).

    No comparison is made fatalities of child pedestrians over the same interval. Pedestrian and cyclist deaths usually track each other closely and help distinguish changes that benefit both types of road user from those targeted specifically at cyclists.

    Finally, a close look at the figures shows there were about 111 child cyclist deaths over 12 years, or about 10 per year in a province of 12 million people. Clearly cycling is an insignificant source of child mortality.

  10. Just a cyclist Says:

    Here is a comment on David Hembrows comment. Your views appear great, wouldn’t it be for the fact that peoples subjective safety while wearing helmets have come from one or two decades of campaigning. And, of course, that the campaigning does presumably not stem from a populations previous subjective safety while biking.
    Anyways, its hard to believe that the introduction of and campaigning for cyclist protective gear use would result in more cyclists as a result of a higher level of cycling subjective safety.

  11. David Hembrow Says:

    “Just a cyclist” has got completely the wrong end of the stick. I’m not calling for anyone to wear protective gear. That would be a continuation of existing policies in English speaking countries which have lead to a decrease in cycling. There is an inverse relationship between wearing of protective gear and cycling. Where it’s, there are fewer cyclists, and they’re usually in more danger.

    What is required is for the streets to be civilized enough that people don’t feel a need to wear a helmet or any other protective gear. You then get a high rate of cycling and a low rate of injuries, as has been achieved in this country.

    Wearing of protective gear is a symptom of an environment where cycling is not comfortable.

  12. Eric L Says:

    Interesting post. Two big problems I have with it. For starters:

    Nearly all of the serious danger to bicyclists comes from drivers. … Consider burglary for a moment: I would suggest the prime responsibility for this social ill lies with the burglars who choose to perpetrate it rather than the householders who are the victims.

    Should the fact that the responsibility for a burglary lies at the feet of the burglar lead me to not bother to lock the door or take other preventive measures? The risk is to me, so I’m motivated to control it. Likewise, if wearing a helmet might save my life I want to do that even if any death would be some driver’s fault. So it’s still a pretty important question.

    Just make that decision is based on your reading of the evidence rather than guesswork, that’s all I’m asking.

    This is just great, after a long post explaining how nobody knows anything and you don’t know anything and the evidence is inconclusive, you say to decide on the evidence and not guess? If you don’t know, isn’t your own decision guesswork?

    Then there is your contrarian speculation about whether helmets ever make a difference in accidents. I’d keep in mind that in most vehicular accidents drivers do hit the brakes and the actual collisions happen at a slower speed than what the driver was initially driving. Also in many bike accidents the biker is knocked off the bike and hits the ground harder than the car, so the situation is not necessarily that different than a kid who falls off their bike. Popular bike accidents not involving fast cars include driving in the bike lane while a parked car opens their door in your path, car making a right turn while a biker is to their right. You may or may not be right about this but it would be nice to see some actual data on what speeds bike collisions happen at to back these guesses up.

  13. Eric L Says:

    David @ 11:

    You’re starting to get at a complication that isn’t brought up above, which is the difference between the individual effect of an individual decision to wear a helmet and the collective effect of cultural changes or public campaigns that lead to higher rates of helmets. It may be the case that, all else being equal, an individual is safer wearing a helmet, but working to convince everyone they shouldn’t be biking without one makes biking less common, drivers more reckless, and is ultimately harmful.

  14. JanetM Says:

    What I find fascinating is that it *isn’t* clear from the evidence that wearing a helmet protects the cyclist from injury that would otherwise occur without the helmet. That something so “obvious” isn’t strongly supported by the data indicates to me that the issue isn’t really about helmets. That this issue provokes such strong emotion suggests to me that the real issue is fear.

    For myself, I admit that, even knowing all this intellectually, I continue to wear a helmet out of fear. I first started riding a bicycle before helmet use was pushed in the United States. I rode a single-speed bike around town. I didn’t even know helmets existed and it never occurred to me to want one. After I got a touring bicycle so I could ride longer distances, I was told (by a bicycle shop) that I should wear a helmet. I began wearing a helmet, and now I feel scared at the thought of not wearing it, even within town.

    I’ve had two falls in which my head (with helmet) hit the ground (I’ve also had many falls in which my head did not hit the ground). Once I slipped in some gravel; once I was hit by a car at slow speed. It’s hard for me to say whether either event would have happened if I hadn’t been wearing my helmet. But afterward, I was glad I had been wearing a helmet, and I think that is what keeps me wearing a helmet for now. I am curious to know at what point I would no longer feel the need to wear a helmet.

  15. Todd Says:

    Let’s try to take one more thing into account. Drivers don’t go out looking to hit a bicyclist. Accidents happen for the most part because the driver didn’t see the bicyclist. It’s not because they were reckless or mean or aggressive. They make a mistake. It’s an accident.

    So, if you believe that wearing a helmet either increases survival or reduces basic injury and you don’t mind wearing one then put it on.

    I wear one not because I don’t feel safe but rather I don’t want my wife to have explain to my kids why I can’t be the dad that they need. Also, I don’t want to be a hypocrite when I make my kids wear their helmets.

  16. Ian Walker Says:

    Eric. With regard to your first point, I also lock my front door! My point was that there is a moral issue here as well as a practical issue. Moreover, the more vulnerable road users acquiesce and protecting themselves against a danger they don’t cause, the easier it becomes for motorists to continue to behave irresponsibly. Most importantly, my point is that this sort of issue shouldn’t be one sorted out by individuals, but rather should be sorted out at the level of the government: just as they legislate to stamp out burglary, they could legislate far more to protect vulnerable road users. None of this precludes the option of locking your door, or wearing a helmet.

    As for your second point, you’re dead right to pull me up on my equivocation: it was a fudge I slipped in with an eye to any litigious folk who might be reading.

    Todd: your reasoning has the same issue as some of the other points I raised. The idea you wear a helmet because you don’t want your wife to have to explain your demise to your children only makes sense if you have already accepted a helmet increases your safety. If some people earnestly believed that carrying a pack of playing cards in your pocket made you safer, would you start to carry one so your wife didn’t have to explain you died from not having one? I’m not saying anything about helmets, here: I’m just pointing out your reasoning only makes sense if you work from the assumption they are helpful, and I’d say that’s not a safe assumption.

    You are right to say that drivers don’t go out looking to have collisions. This is a very good point, and it’s something it’s easy to forget. However, some collisions happen because of misjudgements of bicycles who have been seen also. These are relatively systematic and so not accidents.

  17. Just a cyclist Says:

    “Litigous folks”… Well, isn’t telling cyclists wear protective gear in order not to get harmed by cars a bit like telling women not dress unduly lightly in order not to get molested?

  18. TedRe123 Says:

    I couldn’t disagree more. We absolutely know that wearing protective gear will provide some protection. I’ve crashed twice and struck my head on hard objects twice. Once I smacked the side of a bus, and there was an indent in the helmet. If there was an indent in my head, I might not be writing this now. I can just say by personal experience that if you’re moving, you will strike hard things when you land. If you never crash then you don’t need a helmet. Both times did not involve a car.

  19. Patrick Says:

    TedRe123, you are completely wrong, there is very little credible evidence to support the idea that helmets prevent deaths or serious injury. Every study I’ve read that makes that claim has serious flaws. On the other hand, there is some very strong evidence that says do nothing. In Australia they passed a law requiring helmet use, and although deaths dropped 10%, ridership dropped 30%, so the actual rate of death went up. In the use helmet use went from about 20% to 50% during the 90s, but there was no drop in the number of deaths.

    As has been pointed out numerous times, just because there was in indent in the helmet does not mean you would have suffered any injury.

    Bicycle helmets are designed and tested to lower standards than hockey, football, and baseball helmets. Have you ever noticed that BMX riders wear full head helmets? It’s because standard helmets don’t provide sufficient protection, and BMX bikers are not dealing with the type of impact you get from a car crash.

    Finally, and most importantly, biking is not dangerous. Your chance of death or serious injury is no greater than driving or walking. If you don’t wear a helmet when driving or walking then there’s no legitimate reason you should wear a helmet. If you want to wear a helmet, that is your choice, but don’t go around scaring people away from cycling, you are doing them a dis-service and endangering all the cyclists out there.

  20. Jonathan Krall Says:

    Brilliant post. Nice to see another voice speak up in favor of science and against fear-mongering. Even fear-mongering that seems well-intentioned (see TedRe123 above) makes the world a lesser place.

  21. TedRe123 Says:

    I would have thought that by providing protective gear, you would encourage more people to take up an activity as they would feel safer. Regards my crashes, I don’t know how you can say I’m wrong regarding these, since you weren’t there. I’ve been hit on the head without a helmet(non biking), and I promise you it’s a lot more pleasant with some coverage than without coverage.

  22. GregSea Says:

    TedRe123 – while there may well not be the sort of data necessary to judge whether helmets make you safer, there *is* enough evidence to judge whether by “providing protective gear, you would encourage more people to take up an activity as they would feel safer”. The answer is pretty clearly no.

    The Australian case cited above is one of many that show a strong correlation between helmet promotion and severe drops in cycling – 1/3 is a certainly a huge drop and you see that sort of thing again and again.

    I say that as someone who cycles in Seattle and wears a helmet. In this way I’m like JanetM – it now just feels too weird not to wear one. Last fall on a visit to Holland for a week, however, I biked without one while I was there. In the Dutch context it felt fine. (Largely, I think, because no one else was wearing one – and the drivers there are competent and courteous, and the infrastructure excellent.)

    However we *feel* about helmets, the facts such as they are make it increasingly easy to imagine the following being true:

    * helmet promotion lead to substantial drops in cycling
    * helmet use does not seem correlated with a drop in the death rate per mile cycled
    * substantial drops in cycling are strongly correlated with a greater threat of death from heart disease and diabetes

    In which case helmet promotion will have been a great public policy mistake.

  23. Alex Says:

    “Most bicyclists who die with head injuries also have fatal chest injuries too.”

    I can imagine that helmets aren’t going to make much difference if you find yourself under a tram or lorry, or a motorist ‘doesn’t see’ you (whether or not they looked). Death by bicycle is usually an extreme outcome, much like being attacked by a shark, or bitten by a venomous snake (unless you live in Australia, where these are everyday occurrences?) I’m more interested in the effects of a helmet when knocked off a bike (or falling off, or having a blow-out on a fast descent) and not getting squashed or pulverised. Are helmets effective in reducing the likelihood of head injury in what might be seen as low-impact incidents?

  24. Anthony Says:

    “I’d always recommend helmets for children, whose accidents are slow-speed falls in the absence of traffic.”

    At what age would you suggest that people stop being children, from a helmet -wearning point of view, and start being adults?

    I consider recommending helmets for children to be a Bad Idea for several reasons:

    1) Children’s helmets rarely fit properly, as their heads are growing all the time. They are also rarely worn properly, so would normally just slide off in a crash.

    2) Children need to learn to protect their heads, not to let them hit the ground: wearing gloves is a much better idea, so they learn that the best action when falling off a bike is to protect your head by putting your hands out.

    3) A helmet makes a child’s head heavier and significantly larger, to a greater extent than it does to an adult.

    4) Children have died from being strangled by helmet straps: read the label inside a helmet to see the many instructions and disclaimers.

    5) Having to wear a helmet can put children off cycling as much as adults. We need our children to be as active as possible!

    6) You continue to send out a message that cycling is significantly more dangerous than other normal daily activities, such as walking, climbing stairs, and being a passenger in a car. This also reduces the number of people willing to use cycling as a mode of transport.

    Please don’t pick on children when recommending people to wear polystyrene hats: they need the exposure to risk much more than adults do, and cycling gives them freedom to travel distances that they can’t otherwise do without assistance from a car-driving adult.

  25. Tom from Seattle Says:

    This is a fascinating article, and a great deal of useful give-and-take in the comments. Kudos to you all for avoiding the usual “you’re stupid!” – “no, you’re stupid!” dialog that one normally sees in comment threads.

    I’ve been a ‘full-time-commuting-cyclist’ for most of my adult life. Twice I have been in bike accidents not wearing a helmet in which I had significant concussions (one of which kept me from taking my final exams and graduating from college for a summer.) I have had several bike accidents/falls while wearing helmets, perhaps one every 18-24 months, and have never had a concussion while wearing a helmet. This isn’t anything like a scientific sample, of course. And, the idea that wearing a helmet increases ones’ tendency to push the edges of safety feels right; I know when I’m not wearing a helmet I’m very aware of my vulnerability.
    So, for me, I will continue riding a helmet. My brain is too important to me.

  26. MikeOnBike Says:

    Tom from Seattle said “I have had several bike accidents/falls while wearing helmets, perhaps one every 18-24 months”

    Holy cow, that’s a lot of crashes.

  27. Kim Says:

    The whole helmet debate is a distraction from the real issues for cycling safely, the real risk comes bad driving and it is time to stop blaming the victims.

  28. Ramon Says:

    I bike about 20 miles a day and while I can’t say helmets have saved my life, but I’ve had couple of accidents where the helmet kept me from small injuries… It’s not a big hassle! just wear the damn thing.

  29. Richard Burton Says:

    While Dr Walker is correct to point out that there is a lot of evidence both ways, I don’t think he points out that the research showing massive benefits is rated as the lowest for reliability on international standards. The evidence showing no benefit is not 100% conclusive, but it’s rated much higher for reliability.

    It is also clear that much of the research which shows benefit has been seriously criticised for methodological flaws e.g. the paper which produced the 85% figure also showed that helmets protected elbows and knees. The research showing no benefit has been shown to be much more robust on peer review.

    The biggest problem is that the myth of helmet effectiveness is now embedded in the public consciousness, and like all myths, denials are forgotten and the original belief remains. The situation isn’t helped by a media which endlessly repeats the “helmet saved my life” stories, with no critical examination of the facts. In order to make helmets seem a sensible choice, the media also endlessly implies or states that cycling is much, much more dangerous than it really is. For instance, the BBC has been running a helmet campaign for well over twenty years – just google for cycle helmets and BBC.

  30. Karsten Says:

    What a great “old” post.

    “That Toronto study forgot to mention that cycling dropped between 18-27%. Fewer cyclists, fewer injuries.”

    Do you know the numbers today?

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Traffic Tom Vanderbilt

How We Drive is the companion blog to Tom Vanderbilt’s New York Times bestselling book, Traffic: Why We Drive the Way We Do (and What It Says About Us), published by Alfred A. Knopf in the U.S. and Canada, Penguin in the U.K, and in languages other than English by a number of other fine publishers worldwide.

Please send tips, news, research papers, links, photos (bad road signs, outrageous bumper stickers, spectacularly awful acts of driving or parking or anything traffic-related), or ideas for my Transport column to me at:

For publicity inquiries, please contact Kate Runde at Vintage:

For editorial inquiries, please contact Zoe Pagnamenta at The Zoe Pagnamenta Agency:

For speaking engagement inquiries, please contact
Kim Thornton at the Random House Speakers Bureau:

Order Traffic from:

Amazon | B&N | Borders
Random House | Powell’s

U.S. Paperback UK Paperback
Traffic UK
Drive-on-the-left types can order the book from

For UK publicity enquiries please contact Rosie Glaisher at Penguin.

Upcoming Talks

April 9, 2008.
California Office of Traffic Safety Summit
San Francisco, CA.

May 19, 2009
University of Minnesota Center for Transportation Studies
Bloomington, MN

June 23, 2009
Driving Assessment 2009
Big Sky, Montana

June 26, 2009
PRI World Congress
Rotterdam, The Netherlands

June 27, 2009
Day of Architecture
Utrecht, The Netherlands

July 13, 2009
Association of Transportation Safety Information Professionals (ATSIP)
Phoenix, AZ.

August 12-14
Texas Department of Transportation “Save a Life Summit”
San Antonio, Texas

September 2, 2009
Governors Highway Safety Association Annual Meeting
Savannah, Georgia

September 11, 2009
Oregon Transportation Summit
Portland, Oregon

October 8
Honda R&D Americas
Raymond, Ohio

October 10-11
INFORMS Roundtable
San Diego, CA

October 21, 2009
California State University-San Bernardino, Leonard Transportation Center
San Bernardino, CA

November 5
Southern New England Planning Association Planning Conference
Uncasville, Connecticut

January 6
Texas Transportation Forum
Austin, TX

January 19
Yale University
(with Donald Shoup; details to come)

Monday, February 22
Yale University School of Architecture
Eero Saarinen Lecture

Friday, March 19
University of Delaware
Delaware Center for Transportation

April 5-7
University of Utah
Salt Lake City
McMurrin Lectureship

April 19
International Bridge, Tunnel and Turnpike Association (Organization Management Workshop)
Austin, Texas

Monday, April 26
Edmonton Traffic Safety Conference
Edmonton, Canada

Monday, June 7
Canadian Association of Road Safety Professionals
Niagara Falls, Ontario

Wednesday, July 6
Fondo de Prevención Vial
Bogotá, Colombia

Tuesday, August 31
Royal Automobile Club
Perth, Australia

Wednesday, September 1
Australasian Road Safety Conference
Canberra, Australia

Wednesday, September 22

Wisconsin Department of Transportation’s
Traffic Incident Management Enhancement Program
Statewide Conference
Wisconsin Dells, WI

Wednesday, October 20
Rutgers University
Center for Advanced Infrastructure and Transportation
Piscataway, NJ

Tuesday, March 8, 2011
Ontario Injury Prevention Resource Centre
Injury Prevention Forum

Monday, May 2
Idaho Public Driver Education Conference
Boise, Idaho

Tuesday, June 2, 2011
California Association of Cities
Costa Mesa, California

Sunday, August 21, 2011
American Association of Motor Vehicle Administrators
Milwaukee, Wisconsin

Wednesday, October 26, 2011
Attitudes: Iniciativa Social de Audi
Madrid, Spain

April 16, 2012
Institute for Sensible Transport Seminar
Gardens Theatre, QUT
Brisbane, Australia

April 17, 2012
Institute for Sensible Transport Seminar
Centennial Plaza, Sydney
Sydney, Australia

April 19, 2012
Institute for Sensible Transport Seminar
Melbourne Town Hall
Melbourne, Australia

January 30, 2013
University of Minnesota City Engineers Association Meeting
Minneapolis, MN

January 31, 2013
Metropolis and Mobile Life
School of Architecture, University of Toronto

February 22, 2013
ISL Engineering
Edmonton, Canada

March 1, 2013
Australian Road Summit
Melbourne, Australia

May 8, 2013
New York State Association of
Transportation Engineers
Rochester, NY

August 18, 2013 “Ingenuity” Conference
San Francisco, CA

September 26, 2013
TransComm 2013
(Meeting of American Association
of State Highway and Transportation
Officials’ Subcommittee on Transportation
Grand Rapids MI



October 2008
« Sep   Nov »

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