Feb 27, 2013

Will a bicycle helmet save your head?

New research indicates bicycle helmets are very good for your head even if you collide with a motor vehicle. However helmet-wearing rates by teenagers and children involved in accidents are very low

Alan Davies — Editor of The Urbanist

Alan Davies

Editor of The Urbanist

Proportions of hospitalised cyclists (n = 1859) that sustained at least one injury to particular body regions following a collision with a motor vehicle, NSW 2001–2009; a) all injuries and b) serious injuries (SRR ≤ 0.965). From Bambach et al.

A new paper attracted a lot of attention earlier this month because of a finding that cyclists who ride without a helmet are more likely to take risks.

The Conversation did its own investigation and ran the story under the heading Crash data shows cyclists with no helmets more likely to ride drunk. The Sydney Morning Herald took a more sober approach – it reported Cyclists without helmets ‘likely to be risk-takers’.

Risky behaviour is one of the issues addressed in the paper but these reports distracted attention from a couple of other important results.

The key purpose of the research reported in the paper was to examine the effectiveness of helmets in minimising head injuries in the event of a collision between a bicycle and a motor vehicle.

The paper documents an investigation undertaken by four UNSW researchers, M Bambach, R Mitchell, R Grzebieta, and J Olivier. It’s published in the April 2013 edition of Accident prevention and analysis, a leading journal in this area. There’s an ungated version available here (the file has to be saved first).

Bambach et al examined 6,475 collisions between cyclists and motor vehicles in NSW where the accident was reported to police, hospital data was available if applicable, and the helmet-wearing status of the cyclist was recorded.

The authors were able to combine rich information about the type and severity of injuries with data about the circumstances of the accident.

Their headline finding is that helmets confer a large protective effect in the event of a collision with a motor vehicle.

The odds of sustaining a ‘moderate’ head injury in a collision are 1.9 times greater if the cyclist doesn’t wear a helmet.

However the odds of suffering a head injury classified as ‘serious’ are 2.6 times greater if the rider’s unhelmeted. In the case of a ‘severe’ head injury they’re 3.9 times greater.

When the researchers broke head injuries down by type, the estimated odds of suffering a ‘serious’ or ‘severe’ skull fracture if no helmet is worn is 4.6 times greater.

These findings go against the meme that helmets only offer protection in the event of a minor accident, like simply falling off a stationary bike or while pedalling at low speed.

They contradict the myth that a helmet is useless in an accident with a car. The authors say the research shows the benefit from wearing a helmet increases with the severity of the injury.

It’s also very likely the better odds offered by helmets are under-stated. That’s because the number of riders who were involved in a collision with a motor vehicle but avoided a head injury because they wore a helmet can’t be known.

There’s also some comfort in the finding that more than 90% of cyclists who were in a collision with a car didn’t sustain a head injury.

Those that did, however, were more likely to have collided with a larger vehicle; or to be cycling on a road with higher maximum speeds; or to have disobeyed a traffic signal; or to not be wearing a helmet.

Worryingly, the researchers also found children who were involved in a collision were much more likely to be unhelmeted. Children aged 12 years or less comprised 19% of all those who weren’t wearing a helmet at the time of their accident but just 7% of those who were.

This pattern was similar for those aged 13-19 years. Teenagers made up 35% of all those who weren’t wearing a helmet when they collided with a motor vehicle but 11% of those who were.

Overall around half of all children and teenagers were not wearing a helmet at the time of the accident. This compares with 23% of those aged 20-29, 15% aged 30-39, and 12% aged 40-49 years.

Since it’s about accidents involving motor vehicles, this research can’t tell us if children and teenagers are more inclined to cycle without a helmet. However it shows non-helmet wearers in this age group are significantly over-represented in accidents.

Both children and teenagers who weren’t wearing a helmet were also more likely to have sustained a head injury than their peers who were. They make up 35% of those with a head injury compared to 24-27% of the controls.

As noted at the start, riders who weren’t wearing a helmet were more likely to have been engaged in risky behaviours at the time of the accident.

The net result is unhelmeted riders were involved in more severe crashes, but the authors say the difference in severity is small.

This research bears on the argument about whether or not Australia’s mandatory helmet laws make sense. I interpret the findings as reinforcing the good sense of wearing a helmet when cycling, especially on roads.

I would of course be free to make that choice even if the helmet law were repealed. The question of whether or not helmets should continue to be mandatory must be considered in the context of other arguments, especially the claim that the law deters cycling.

A more pressing issue though is the over-representation of under 20s in accidents with cars; their higher rates of head injury; and the remarkably low helmet-wearing rates of those in this age groups who’re involved in collisions with motor vehicles.

(Visited 11 times, 1 visits today)


Leave a comment

Your email address will not be published. Required fields are marked *

52 thoughts on “Will a bicycle helmet save your head?

  1. Burke John

    Thanks Rides to Work #51 … I’ve always considered this issue a statistical morass. Once I visited an ACT polititian to warn her about upcoming changes to E-bike laws which seemed to promote them but actually designed to stifle their uptake. These laws are now in effect.

    It was at that meeting that my interest in MHL was really ignited, previously having actually assumed (naively indeed) that all educated or informed individuals would view MHL with some suspicion or unease. This polititian at first said there was no evidence of the dangers of MHL but finally stated the following position. The perception of the protection provided by MHL was more important than any statistic anyhow. Asked for a clarification she said that because most people intuitively felt helmets were safer then that was it and no studies were needed beyond that poll.

  2. RidesToWork

    “Helmets were made compulsory in NYC for under 15s in 1994. Of course the report doesn’t give the helmet wearing rates for children and adults not killed or in accidents, but very much doubt it was just 3%.”

    The reported wearing rate for injured cyclists was 13%. They also quote surveys showing only 14-20% of High School Students said they wore a helmet even once during the past year. However, a survey in 2004 found pretty high wearing rates on off-street paths (49%), compared to 22% on streets.

    This seems to be the opposite of the UK where a very high proportion of London rush-hour commuter cyclists were observed to wear helmets, but much lower proportions on quiet streets at other times. This may have changed with the introduction of Boris Bikes.

    The patterns are different again in post-law Australia: “excluding cases where helmet wearing was not known, reported accidents in NSW in the three years since the helmet law show 80% of cyclists killed and 80% of those seriously injured wore helmets at the time. These proportions are almost identical to wearing rates in street surveys (85% and 83% for adults in 1992 and 93 respectively; 76% and 74% for children.”

    Similar data for Victoria also show helmet wearing rates of fatally injured cyclists that were almost identical to population wearing rates.

    The above examples illustrate just how difficult it is to make valid deductions from statistical comparisons of helmet wearing rates of injured cyclists – helmet wearing rates are different for sober vs intoxicated cyclists, safe vs more dangerous streets, the age of the cyclist etc.

    It’s therefore far simpler to look at injury rates before and after the introduction of MHL in Australia – did they increase or decrease injury rates? All available evidence points to increased injury rates compared to what would have been expected without the law.

    Governments don’t want to admit this, so they ‘analyse round’ the problem. In Vic, they looked at percent head injury (cyclists only, ignoring the similar trend for pedestrians). Then, when they found that the results were no different to pre-law trends, they switched to an analysis of numbers of head injuries. It showed a significant decrease, just like the number of non-head injuries, simply because of the reduction in cycling. But the comparison of numbers of cyclists injured in bike/motor vehicle crashes compared to the same data for pedestrians, and numbers of cyclists counted pre and post-law suggest that if anything, the law increased the risk of serious or fatal injury.

    In NSW, they hunt to find a significant effect was even more complicated involving logarithmic statistical model, and individual prior adjustment of adult and child data for seasonal effect. Simple statistics comparing the number head injuries to child cyclists with the number of child cyclists counted in surveys shows that head injuries per cyclist increased – but that subject is, of course, taboo!

    Interestingly, although the 3% helmet wearing rate of fatally injured cyclists in NY may be correct, the main US databases of fatal traffic injuries appears to substantially under-report helmet wearing rates for cyclists. According to Riley Geary, the main FARS database is compiled from forms which usually don’t have a check box to say whether or not a helmet was worn, and these cases seem to end up as ‘no-helmet’ records – see

    The US High School survey shows that US helmet laws don’t seem to result in large increases in helmet wearing rates, and may also have the unintended consequence of teaching children that its OK to disobey road safety laws. However they do have some effect, but again the unintended consequences seem to be more significant than the reasons for passing helmet laws. “helmet laws are associated with reductions in bicycle-related head injuries among children. However, laws also are associated with decreases in non-head cycling injuries, as well as increases in head injuries from other wheeled sports. Thus, the observed reduction in bicycle-related head injuries may be due to reductions in bicycle riding induced by the laws –

  3. SBH

    Ooh yes your all so right. Based on the inescapable force of your arguments, I completely recant and now firmly advocate against MHL!

  4. Dylan Nicholson

    SBH I don’t think you’ve convinced anybody here that it’s a red herring. It may seem like ‘endless bellyaching’ to you but I’ve definitely noticed a gradual shift in public opinion re MHL in the last few years. I’m still hopeful we’ll start to see exemptions introduced at some point, or at least a policy of not enforcing the rule when it’s clearly not productive (already achieved in Darwin and a few other places). And I don’t know of any cycling advocate that thinks scrapping MHL is the “main game”: it’s just part of the picture.

  5. St Etienne

    “If you all spent as much time agitating for safer cycling infrastructure as you did endlessly belly-aching over this red herring we all be better off.”

    Many people who oppose or question the law are already involved in bike advocacy SBH. Comparing them to those in the “climate change dopes camp” is not only utterly offensive but speaks volumes of your ignorance on this matter.

  6. Burke John

    SBH #46..Most governments and constituents thereof oppose helmet fanaticism and consider MHL supporters in fact have “dumb views”.

    However none to my knowledge has suggested this tiny Antipodean minority should be barred from voting. In fact voting is exactly how a certain form of government works and lighting a candle on issues is part and parcel of that process also.

  7. SBH

    because st etienne the arguments advanced are as ignorant of government process as the are deliberately blind to scientific consensus. And because I’m really bored, horrified and scared in equal measure that people with such dumb views and such an ignorance of how government works are allowed to vote. Even your example equivocates and gives his opinion not a researched data informed answer. That kind of dichotomous arguing is well at home in the climate change dopes camp.

    And ikkie, it is not a valid argument to simply say because one thing happens in one set of circumstances the same actions should always be take to solely a problem in a different set of circumstances. It’s a simplistic silly argument that’s without merit.

    If youall spent as much time agitating for safer cycling infrastructure as you did endlessly belly-aching over this red herring we all be better off. I mean light a candle and stop cursing about the darkness for christ sake.

  8. St Etienne

    SBH, I’m not sure why you dismiss opponents of the law as being in same league as AGW deniers. Opposing the law does not mean denying the efficacy of helmets; it’s simply about questioning the unintended consequences of the law in terms of decreased cycling participation. The authors of the study cited in this piece are insistent (almost to the point of pomposity) that the law has never been a barrier to cycling, whereas myself and just about every cycling organisation in the world have no doubt that it is has a very negative effect on utility cycling.

    Just a recent example: the head of road safety and traffic management in Copenhagen was asked about the importance of walking and cycling for public health. His response:

    ‘Yes, absolutely. Using the same techniques we calculate that the health effects from exercise that you get from cycling are very big, and that it’s actually like smoking or non-smoking. It’s huge numbers, also in terms of money. The same reason that if you make the calculation on helmets: if you wear helmets you probably have less injuries, according to the statistics, but you also lose cyclists. And the amount of money lost to society from this loss of cyclists is higher than the benefit from the reduced number of injuries so it’s best business to not have mandatory helmet laws.’

  9. IkaInk

    @SBH – And of course, all those riders whose freedom to ride unencumbered is so rudely truncated, will sign waivers so that they will pay the full cost of any treatment for head injuries, eh?

    Spread across society the cost you are talking about is so insignificant it really isn’t even worth mentioning. Following the same logic should we also expect all risk takers to sign these waivers? Skiers, snowboarders, skateboarders? Drinkers, smokers? People that walk in storms? People that work risky jobs? Where should we draw the line here?

    Bicycle riding simply isn’t that dangerous helmet or none.

  10. Burke John

    Harvey #42- At least the Australian government funded helmet advocacy study is generally seen as a local cultural thing internationally…soon we’ll be able to replace our koala key-ring fluffies with mini bicycle helmets!

  11. Harvey

    It is incredibly gullible to believe at face value a “study” done by helmet advocates.

    Their first attempt, claiming an “up to 29%” change despite inconclusive underlying data, did not fool many people:

    Their next attempt included data showing that head & arm injuries increased significantly after the helmet law. Yet somehow they found a way to claim that this meant the helmet law was a great idea. That did not fool many people either:
    The commentary is quite insightful, successfully predicting that “we haven’t seen the last of government-funded research showing that helmet laws are great actually,”

    Another insight was: “It’s generated some nice headlines and superficial reinforcement for the helmet law (which is probably what the government were really trying to commission)”

    I wouldn’t be surprised if, within a year, an independent party has a close look at this “study”, and finds out that its claims are misleading and invalid.

    In the meantime, helmet believers can cheer up.

  12. Burke John

    Such an interesting topic though I honestly don’t understand why anyone would be passionate about pro-helmet wearing except for themselves or their kids. It can only be explained by car culture prevailing as I see it.

    Underlying all for me is an even bigger question though. Do I care more about whether you crack your head or the planet is killed by pollution and could MHL affect the second situation?

    Opening myself up for attack, I say its a no-brainer, the planet wins and sorry about your head.

  13. Alan Davies

    Strewth #38:

    If we really believed that, we would have mandatory helmets in cars

    No, I can’t agree with that proposition. We know helmets in cars would confer an additional protective effect (after all, racing drivers wear them), but we won’t do it because (a) it would offer marginal benefits given other safety devices (b) it would require a re-design of new cars and make older cars unusable (c) it’s inconvenient (relative to the pay-off), (d) the type of helmet required to bestow even a marginal advantage in a car would be expensive and bulky, and (e) most of us drive and hence would be affected.

    The pain of wearing helmets in cars would be too high compared to the benefit. We don’t come to the same conclusion wrt bicycle helmets though, partly because I suspect they provide a bigger benefit for cyclists (than car helmets would for drivers) and partly because very few people cycle on roads i.e. most aren’t affected and so are happy for the tiny minority to wear (or put up with) them.

    Having said that, the main argument now for MHL is that it’s already the law and the vast, vast majority of Australians are perfectly happy with it.

  14. Alan Davies

    Some findings from a report by NYC on cyclist fatalities and serious injuries:

    – Between 1996 and 2005, 225 bicyclists died in crashes.
    – Nearly all bicycist fatalaties (92%) involved crashes with motor vehicles
    – Most fatal crashes (74%) involved a head injury.
    – Nearly all bicyclists who died (97%) were not wearing a helmet
    – Large vehicles (trucks, buses) accounted for one third (32%) of fatalities.

    Helmets were made compulsory in NYC for under 15s in 1994. Of course the report doesn’t give the helmet wearing rates for children and adults not killed or in accidents, but very much doubt it was just 3%.

  15. Strewth

    Alan #35, I think this goes to the root of the MHL issue. We can see why it was possible politically: cyclists in 1990 were a minority group without much political clout, and it was an easy way for politicians and ‘safety experts’ to take a strong position on road safety.

    But I suspect MHL remains popular today for a variety of reasons that fail to apply the available facts consistently. So the most common responses I get when I ask why people support mandatory helmets are:

    (a) “Because helmets prevent head injuries, it’s just good safety practice to mandate them for all activities that pose a risk of head injury.” If we really believed that, we would have mandatory helmets in cars, and we’d follow the Japanese practice of putting helmets on kids when walking them to school.

    (b) “Cyclists need helmets because cycling is so much more dangerous than driving or walking.” This isn’t supported by the statistics, once you account correctly for the level of cycling activity. Some car journeys put you at the same or greater risk of death from head injury as from the average bike journey.

    (c) “Bike helmets are payback for the fact that motorists have to wear seat belts.” Wearing a helmet on a bike may be a minor inconvenience, but it’s still perceptible compared with the truly trivial inconvenience of putting on a seat belt in a car. Seat belts have been more effective in preventing injury in car crashes than helmets have been in preventing cyclist injuries.

    (d) “After falling off my bike I would never ride without a helmet again.” Comparing the cycling populations of Australia and Europe on a range of demographic factors, it’s evident that cycling in Australia skews much more toward a risk-taking minority of the population. Day-to-day cycling experience in countries without MHLs just isn’t as replete with anecdotes of heads hitting pavement – aside from those who cycle for sport, most of whom wear helmets anyway.

    Sure, in a narrow sense it does good to require cyclists to wear helmets, but I suspect we’d see a lot more casual cycling by Joe Public if we took a more European approach to the safety issue.

  16. SBH

    Alan, you again fix Reason firmly in her seat. A good way for me to start the weekend

  17. Dylan Nicholson

    SBH if the law were restricted to major roads, I’d largely agree (though still prefer not to have it). But it’s not…

  18. Alan Davies

    My “Molly Law” comment was of course meant tongue-in-cheek. There really is a serious problem with Middle Aged Men On Ladders (MAMOLs) in the home but mandatory helmets wouldn’t work for the reasons SBH points out.

    I wanted to make the point that all these references to car drivers, MAMOLs, etc not being compelled to wear a helmet are beside the point.

    Helmets very likely really would help in those cases but we’re not prepared to pay the price i.e. the political system wouldn’t dare. It would be too inconvenient, too hard to enforce, etc.

    MHL is simply one of those cases where we were prepared to pay the price i.e. the political system took it up and won. If you like, the MHL lobby got away with it. Probably because at the time hardly anyone cycled except children.

    There’s still an entirely separate argument about the deterrent effect of MHL and even, perhaps, an argument that helmets don’t even work (i.e. we were conned), but the hypotheticals are irrelevant.

  19. Strewth

    SBH #31, out of curiosity: do you wear a helmet in the car? If not, why not? (Don’t assume your seat belt is going to prevent you suffering a head injury in a crash.)

    At the time the mandatory helmet law was introduced, the rate of head injury deaths per million hours was 0.19 for cyclists and 0.17 for motor vehicle occupants – seat belts notwithstanding.

  20. SBH

    and there are about 3 times more deaths from bicycle related accidents than are caused by ladder falls

  21. SBH

    BTW ladder use in the workplace is the subject of very detailed and proscriptive legislation.

  22. SBH

    And of course, all those riders whose freedom to ride unencumbered is so rudely truncated, will sign waivers so that they will pay the full cost of any treatment for head injuries, eh?

    The ladder argument really is a peach. You have one activity (bicycle riding) which is plainly observable, happens on public streets and where compliance is easily enforceable, against an activity that has none of those characteristics. No statistics are advanced to support the case. Talk about your straw man!

    The anti MHL argument is plainly one of the silliest arguments (after climate change) on foot at the moment. Casting it in a rights perspective is ludicrous, disingenuous and without merit as it utterly fails to take into account the rights of the community at large or the rights of injured persons. Like fluoride in water, vaccines, seat belts and drink driving some contrarian nong will advance specious (or more oft just plain dumb) arguments why the particular safety measure is without merit. It’s old, boring anti-intellectual, counter productive claptrap.

    So enough eh? Do something useful with your time.

    …..sits back – awaits ignorant, subjective flame

  23. Dylan Nicholson

    AD, that’s the thing though, it really IS just as silly, if not sillier, to mandate helmet wearing on bicycles as it would be to mandate helmet wearing while climbing ladders.

  24. SBH

    I think that’s right Alan but I am aware that the enforced practice of wearing sun protection on building sites has become widespread. Employers insist to respond to OH&S liability and treat sun protection as safety equipment. You could consider it delegated mandation in that legislation requires employers to provide safe workplaces but doesn’t exhaustively prescribe how that can be achieved.

  25. Alan Davies

    Dylan Nicholson #26; Strewth #27:

    The big gain would be in a ‘Molly Law’: mandating that middle aged men who climb ladders must wear a helmet!

  26. Strewth

    Dylan #26: I agree 100%. My own experience is that we can prevent lots of head trauma by mandating helmets for (a) DIY builders, (b) anyone loading or unloading goods from hatchbacks, and (c) anyone walking on an uneven footpath. Of all the blows to the head I’ve suffered over the years, precisely none involved a bicycle.

    Of course that’s all anecdote, and of about as much value to population studies as mikeb’s anecdote at #21, but whatever.

  27. Dylan Nicholson

    mikeb, I’d certainly accept the fact that helmets are mandatory while riding bicycles has saved a few lives here and there. They’d almost certainly save even more lives if they were mandatory while performing various other activities, and there’s certainly a much stronger argument for mandating, e.g. wearing of inflatable devices while swimming, or cars being fitted with far more safety devices than they are now (including speed limiters and breathalyzers). But there are far more effective and defensible methods governments could use to save lives than to threaten people with fines if they choose to undertake certain personal risks, especially when there are clear downsides to the discouragement effect of such regulations.

  28. Ian Brown

    Given the contested nature of the accident / injury statistics, is it not time for some crash modelling to be performed – ie using dummies as in motor car safety tests. Perhaps this has been done somewhere – any comments?

  29. Alan Davies

    SBH #22:

    Ah, my kids had to wear a hat at primary school too, now you remind me, but no legal compulsion outside school. Not mandatory at their (Melbourne) high schools though other than during sport (in fact my son’s school doesn’t even have a formal hat as part of the uniform).

    When I was at high school in Qld back in the day, wearing a hat when in uniform outside school was compulsory but that was for appearances, not health. Never heard of hats being mandated for adults (civilians) though, like bicycle helmets are.

  30. IkaInk

    @Alan, SBH, Geoff McLeod – I can’t provide citations that prove this, but I recently heard an interview with some American Medical Professionals that had studied Vitamin D deficiency rates around the world. Interestingly whilst Australia has the highest rates of skin cancer in the world, it also has the highest rates of Vitamin D deficiency. The conclusion the interviewees came to was that whilst a sizeable part of the population has continued to ignore the “Slip, Slop, Slap” message, or have been alive well before it was so wide-spread; another, larger part of the population have taken that message to heart so strongly they will virtually never venture into the sun without protection and thus are missing out on Vitamin D exposure.

    The similarities have some similarities to the MHL debate. Of course skin-cancer is far more serious than Vitamin D deficiency. Of course head injuries are more serious than a drop in exercise. However in both cases, the more serious concerns are likely to affect a much smaller part of the population. Still, I’ll continue wearing sunscreen/helmets when I think the risk of sun-burn/accidents is fairly high.

  31. SBH

    AD No. 20, yes, hats are mandatory at my children’s primary school. ‘No Hat – No Play’ Many schools enforce this policy

  32. mikeb

    All I know is that when my head hit the ground the helmet in between was mighty appreciated. Would I have been wearing one if it wasn’t mandatory? Most likely not – and I am well & truly an adult. Kids just would not wear them if they didn’t have to.

  33. Alan Davies

    Geoff McLeod #18:

    The study examined all collisions with a reportable injury between cyclists and motor vehicles so accidents involving “lycra louts” would’ve been picked up. For the purposes of this study, “risky” has to be defined by information recorded by the police attending the accident e.g. was the cyclist disobeying the road law at the time of the accident.

    Not sure if your 80% stat is right (sounds it though), but there are a number of reasons that explain the spectacular and sustained drop in cycling by schoolchildren better than the helmet law. The key ones are more working parents (so driven to school), more students attending private schools (so take PT or driven), more fear of traffic and “stranger danger” (so driven to school).

    Your skin cancer example is an interesting one. Has anyone ever suggested making sunhats mandatory for children and adults in summer?

  34. Alan Davies

    Strewth #17:

    These are the very issues that aren’t examined closely enough. Children who walk to school instead of cycle get more exercise. This longitudinal British study finds that children who’re driven to school are just as active as those who aren’t i.e. they “catch-up” in other ways.

  35. Geoff McLeod

    Unhelmeted cyclists are risk-takers? There are large groups of lycra guys wearing helmets travelling at lethal speeds every morning as they weave though traffic. Are they not risk takers too? Were these guys included in the study? What is defined as a risk? I don’t see groups of unhelmeted urban cyclists doing that kind of riding.
    I put a wide-brim hat on my kids when riding around during the day. As a responsible parent I’m avoiding a significant risk or sun damage because Australia has a 1 in 3 skin cancer rate. Helmets don’t offer the same protection as a hat but this stupid nanny state law tries to prevent me from averting this huge killer of our population. Obesity is also a risk – 17000 of us die from it and it costs 21 billion per year. 80% less school kids cycle today that pre helmet law. Was the obesity risk factored in to the study? Sounds like cherry picked argument to me.

  36. Strewth

    However Alan #16, there’s the trend toward increasing rates of childhood obesity, which the public health people link in part with reduced exercise levels, including cycling. And of course there’s the dramatic decline in rates of walking and cycling to school (which admittedly goes back further than helmet laws – they hardly helped though).

    For kids who aren’t sports mad, walking and cycling are about the only decent day-to-day exercise they’re likely to get in a modern urban environment.

  37. Alan Davies

    Strewth #15:

    There’s another issue too – it’s taken for granted that those deterred from cycling (a) need or would benefit from the additional exercise and (b) would not be doing something else equally or more beneficial for their health. That’s arguable, especially in the case of children, who are the group most deterred by helmets.

  38. Strewth

    Dylan #14: I think that’s the question. Let’s not kid ourselves though – it’s likely not exclusively minor head injuries that were prevented by putting helmets on every cyclist. Just as there are numerous severe head injuries suffered today by motorists, some of which would be prevented by putting helmets on everyone in a motor vehicle. (As the trauma surgeons know only too well, yet rarely speak up on with the same vigour with which they urged helmets on cyclists 25 years ago.)

    I myself think the BMA’s position from the 1990s remains valid, despite their more recent change of heart. There is a clear trade-off between reducing injury rates by discouraging cycling and forcing the remainder to wear helmets on the one hand, and reducing the incidence of lifestyle diseases by encouraging cycling on the other. The BMA seems to think there is clearer evidence for head injury reduction from helmets post-2000 than there was in the 1990s and less evidence for deterrence of cycling; but as we see, not all the new research points in the same direction.

  39. Dylan Nicholson

    Strewth, agree with you 100%, but the other factor is: is preventing a few minor head injuries worth the downsides?
    It’s like the town in Holland where they ripped out the traffic lights. Minor incidents went up quite a bit (not just initially, but remained higher than before), but the massive reduction in major incidents and the other upsides more than compensated for this by any sane measure.

  40. Strewth

    John Burke #12: I think it’s fair to admit that mandatory bike helmets in Australia have prevented a number of cyclist head injuries, and not just by keeping cyclist numbers lower than they would have been otherwise.

    At the same time though, they’ve made it much harder to build up a pro-cycling attitude in the general population. People are now convinced that cycling is a more dangerous activity than the statistics warrant (even conflating it with motorcycling that has about 10 times the injury rate), and even today the regular cyclist population is dominated by young male risk-takers in a way it’s not in Europe or Asia. Motorists are reinforced in their habits by the belief that not only are they more law-abiding than those horrible cyclists by virtue of their ‘normal’ status, but they’re also keeping themselves and their kids safer by using the car.

    It’s interesting to ponder whether mandatory bike helmets would succeed as policy today if it were being newly proposed. I suspect that compared to the environment of the late 1980s, it would be more strongly recognised as a deterrent to cycling and there’d be more of an effort to weigh up the costs and benefits, with many of the policy makers themselves having personal experience of cycling to inform their decisions. It strikes me that cyclists themselves had very little voice in the original decision to impose mandatory helmets.

  41. Burke John

    Would a “risk taker” include someone who doesn’t drive their kids to school? Everything is relative.
    Not forgetting also that if this study is to be relied on, then its time for walkers and motorists to be compelled to wear helmets also.

    Speaking of memes though, notice how pro MHL advice always refers to “head injuries” whilst anti MHL to “brain injuries”.

  42. Strewth

    On the wider point about the effect of mandatory helmets on cycling, some new research from the USA reinforces earlier findings about deterrence. This is from the National Bureau of Economic Research:

    Basically, a large number of US states have imposed mandatory helmet laws for children. The linked paper concludes the laws are associated with a 13% reduction in head injuries, but also with a 9% reduction in non-head injuries for which it can safely be said helmets are not protective. This suggests at least a large part of the reduction in head injuries may arise from a decline in cycling rather than just the protective effect of helmets.

    Interestingly, it is also found that where the law is imposed specifically for bicycles and not for other ‘wheeled toys’ like scooters or skateboards, they are associated with a 25% *increase* in head injuries and an 11% increase in all injuries associated with wheeled toys. The underlying upward trend in wheeled-toy use may explain part of this, but is likely a minor factor: when the helmet law covers wheeled toys as well as bicycles, this is associated with a 3% increase in wheeled-toy head injuries and a 3% reduction in wheeled-toy non-head injuries (which are far more common than head injuries).

  43. SBH

    ridestowork? awaiting your rebuttal

  44. Alan Davies

    Bill Bunting #8:

    As this study is only concerned with injuries from collisions between motor vehicles and cyclists, it’s highly unlikely it would include any injuries from accidents that occurred on off-road cycle ways and paths.

  45. Bill Bunting


    “Since it’s about accidents involving motor vehicles, this research can’t tell us if children and teenagers are more inclined to cycle without a helmet. However it shows non-helmet wearers in this age group are significantly over-represented in accidents”

    is the stupidity of this kind of study particualarly when it is taken as the basis for blanket conclusions. For starters the question “will a helmet save your head” omits the end of the question, “at the expense of your neck?”

    As I have reported polystyrene helmets have an undesirable property in that they grip rough surfaces and can and do cause severe neck injuries.

    The logic in the extraction where conclusions are drawn makes as much sense as saying that wearing bullet proof jackets reduces the risk of severe injury when shot therefore we should mandate that people should wear bullet proof vests in public.

    By far the greatest cycle mileage is done at slow speed off road on cycle ways and paths where the incidence of head hits is near zero. So we should definitely not include these figures in our considerations regarding general helmet use.

    Yes, if you are going to go fast on roads then wearing a helmet is advised. But casual family cycling?

    Australian life is becoming increasingly dominated by the grumpy old man command generation.

  46. Strewth

    Thanks Alan – it’s good to see some evidence at last that helmets are effective in at least some motor vehicle collisions.

    That said, I’m not a huge fan of the case-control methodology when applied to injury prevention. Although it makes the task of collecting and analysing data more straightforward (and is very popular for that reason), it doesn’t provide a direct measure of comparative risk, because it excludes from consideration the ‘silent’ population of the non-injured. It means that the conclusion of the study can theoretically be disputed on the basis that the higher proportion of non-helmet-wearers in the head-injured cases is due to the systematic risk-taking behaviour of the non-helmet-wearing population, rather than their failure to wear helmets per se. The fact that non-head injuries are also more prevalent in the non-helmet-wearing population lends support to this alternative interpretation.

    Because the study excludes non-injured cyclists, the authors suggest that the protective effect of helmets is underestimated because the excluded instances may include cases where a helmet was decisive in placing a cyclist in the non-injured population rather than the study population. But without the data on non-injured cyclists this is pure speculation, since the data also exclude cases where cyclists avoided injury in collisions due to protective factors other than a helmet, and the size of the ‘helmet effect’ relative to this cannot be measured.

    Despite all that, I’d suggest there’s enough evidence here for a protective effect due to helmets. The statistic I find most convincing from a lay perspective is that while non-helmet-wearers are 25% of the entire study population and 30% of those with injuries other than head injuries, they are 40% of the head-injured cases. So if one uses non-head injuries as a proxy for risk-taking behaviour, it shows that this is a significant factor in the higher rate of head injuries among non-helmet-wearers but also that the use or non-use of helmets is a factor on its own. Previous studies had been inconclusive on this point.

    As you say, the results here are not decisive either way on the question of whether the law should mandate helmet use, due to the deterrent effect of helmets on cycling. It would be interesting too to see a study of this nature in a jurisdiction where helmet use is voluntary and the non-helmet-wearing population is more representative of the entire cycling population.

  47. Dylan Nicholson

    C’mon Nik, my 7yo walks around everywhere with his helmet on, he thinks it’s cool!
    I actually think the idea of knowing that when you reach 12 you’re now legally allowed to ride without your helmet would appeal to many kids under 12, sort of like a rite-of-passage.
    Though I’d be ok if MHL was still in-place for on-road riding for 12-18yos.

  48. Nik Dow

    Yes, if you want to turn people off cycling, best to start young.

  49. Dylan Nicholson

    Oh…I missed his “for the young”. I’m fine with helmets being compulsory for, say, under 12yos. Over that, I’m not convinced the benefits outweigh the cons.

  50. Alan Davies

    Dylan Nicholson #2:

    “indefensible” and “quite counter-productive” are strong terms.

    There’s a long list of jurisdictions across the world that make helmets mandatory for child cyclists but not adults (e.g see this paper). I note that most anti-MHL advocates confine their argument to adults.

    Children and teenagers are subject to more legal controls (protections) than adults, reflecting the view that they’re less able to make judgements about what is and isn’t in their long-term interest. Best to be cautious seems to be the rule.

  51. Dylan Nicholson

    hk, no it does not. It very much suggests that helmet wearing should be strongly encouraged, and it’s a good thing that it’s largely normalized in this country, but for it to be a fine-able offence to choose to ride without a helmet, even when just trundling along a dedicated bike track for a few km at jogging pace is not just indefensible but quite counter-productive.

  52. hk

    All seems to add up to the case for helmet wearing for the young to remain helmet mandatory as it is some places outside Australia and NZ.
    My “over the handle bar” observations are that more enforcing of helmet wearing would not go astray to prtect the young.

    Chatting with non helmet wearing kids indicates their non-compliance is just another example of self expression and game playing for a dare. If they can get away with it, time trials and acrobatics without helmets on bikes is great training for burn-outs and street drags later in life.

Leave a comment

Your email address will not be published. Required fields are marked *

Share this article with a friend

Just fill out the fields below and we'll send your friend a link to this article along with a message from you.

Your details

Your friend's details