Do you wear a helmet?

[beroepsrenner]

I spent at least 15 years of my 23 year racing career training without a helmet and when racing in a helmet optional country always chose not to. Ironically the worst head injury I ever received ( resulting in cerebral hemorage) was while training on a velodrome wearing a helmet. Now days I'm no longer bullet proof and feel naked if not wearing one....at least while riding anyway

 

[elapid]

The bottom line is i have never heard about a cyclist who dies BECAUSE he was wearing a helmet.
They might not always save you but i doubt they would ever cause a death,
maybe if we find out later that they attract lightening strikes i will stop wering them when it gets cloudy...

There was a thread on this forum a little while ago discussing a cyclist who was shot by a car driver because the driver thought the cyclist was being unsafe in the way he was riding with his daughter. The bullet embedded in his helmet and he survived with few injuries.

I also just finished watching a Discovery Channel show called When Animals Attack (or something like that). A girl MTBing in Alaska was attacked by a brown bear and her helmet took the brunt of the attack and she survived as well.

Roads, trails, bears, and bullets. Helmets protect against multiple possible sources of injury!

 

[Cobber]

Correct me if I'm wrong but don't the French have a better casulaty rate for cyclists than anywhere in the English speaking world?

Not sure about the stats, but drivers in France are extremely courteous to cyclists. I was cycling in Lyon earlier this year and cyclists have right of way on the roads at all times! It is like a cycling utopia over there. I would still wear a helmet because, well, accidents happen. But if there was a place where I would consider not wearing a helmet, it'd be France!

 

[Cobber]

There was a thread on this forum a little while ago discussing a cyclist who was shot by a car driver because the driver thought the cyclist was being unsafe in the way he was riding with his daughter. The bullet embedded in his helmet and he survived with few injuries.

I remember that! And the cool thing was that the guy who was shot was a member of these forums!

Update: Here's a link to the thread.

 

[philcrisp]

No idea of the forces involved. Without a helmet, drop yourself from 3ft, 4ft, and 5ft head first onto a piece of concrete placed on top of a calibrated force plate. Do some CAT scans of your brain 1 minute, 30 minutes, 1 hour and 12 hours after each impact then report back your findings.

Orr email mythbusters "cycle helmets do nothing, fact or myth"? They would find out the kind of energy needed to jarr the brain hard enough to cause life-threatening swelling, then they would set up a crash test dummy at about 70kg in weight etc etc

Can I rephrase that question? If a pedestrian falls over and hits their head do they need a helmet. How many of us know someone who's suffered serious brain injury in that situation. What I'm trying to get at is that the testing standards are for relatively low speed impacts and that kinetic energy rises exponentially with speed. It makes me extremely suspicious of claims that helmets have saved lives when riders make swift and full recoveries from head injuries unless of course the helmets available substantially exceed the testing standards. I've never seen that claim in advertising for XC/Road helmets.

 

[rhubroma]

I live in Italy and I don't wear one. Only when racing. I hate them and couldn't care less about taking risks. It's my choice and I find them to be so conformist and another gaget which has been foisted upon us by the corporate world.

A helmet has never saved my life. It only makes my head hotter in the summer. And again, I don't care about the risks nor what the moralists have to say.

Of course, anybody that chooses to wear one is their business. So stay out of mine.

 

[philcrisp]

Not sure about the stats, but drivers in France are extremely courteous to cyclists. I was cycling in Lyon earlier this year and cyclists have right of way on the roads at all times! It is like a cycling utopia over there. I would still wear a helmet because, well, accidents happen. But if there was a place where I would consider not wearing a helmet, it'd be France!

That's why the argument about legal compulsion revolves around a lot more than the effectiveness of helmets.

 

[TheDude]

Can I rephrase that question? If a pedestrian falls over and hits their head do they need a helmet. How many of us know someone who's suffered serious brain injury in that situation. What I'm trying to get at is that the testing standards are for relatively low speed impacts and that kinetic energy rises exponentially with speed. It makes me extremely suspicious of claims that helmets have saved lives when riders make swift and full recoveries from head injuries unless of course the helmets available substantially exceed the testing standards. I've never seen that claim in advertising for XC/Road helmets.

I have a friend that spent several weeks in hospital and 6+ months in rehab for a head injury from falling-over while walking on crutches. To this day he has never recovered his sense of smell. If pedestrians had to wear bike helmets, it would save them from injuries as well. It is just that the rate of injury is much higher for cyclists.

 

[cromagnon]

I have a friend that spent several weeks in hospital and 6+ months in rehab for a head injury from falling-over while walking on crutches.

I trust you took the p1$$ mercilessly? (why is the p word censored? ridiculous)

 

[philcrisp]

I have a friend that spent several weeks in hospital and 6+ months in rehab for a head injury from falling-over while walking on crutches. To this day he has never recovered his sense of smell. If pedestrians had to wear bike helmets, it would save them from injuries as well. It is just that the rate of injury is much higher for cyclists.

So why aren't RoSPA etc telling us to put on head protection before we get out of bed in the morning? Why aren't the RAC recommending that all occupants of motor vehicles wearing FIA approved helmets, HANS devices and fireproof suits. (substitute local general saftey and motoring organisations.) I still haven't seen sufficient credible evidence that the risk of head injury is for most cycling applications high enough or that helmets mitigate it to a significant degree. I repeat has anyone demonstrated that helmets make a significant difference to the casualty rate? No one has tried to answer that question directly.

 

[elapid]

So why aren't RoSPA etc telling us to put on head protection before we get out of bed in the morning? Why aren't the RAC recommending that all occupants of motor vehicles wearing FIA approved helmets, HANS devices and fireproof suits. (substitute local general saftey and motoring organisations.) I still haven't seen sufficient credible evidence that the risk of head injury is for most cycling applications high enough or that helmets mitigate it to a significant degree. I repeat has anyone demonstrated that helmets make a significant difference to the casualty rate? No one has tried to answer that question directly.

I am not sure why you have such a bee in your bonnet about this one. If you look at the poll, over 70% of respondents voluntarily wear a helmet despite it not being compulsory. You don't have to wear a helmet, but you are not going to convince to 70% + of respondents to not wear a helmet because you disagree with compulsory helmet laws in some countries.

As for the casualty rates, plenty of the papers I listed at the start of this thread showed significant reductions in head and facial injuries with helmet use. In regards to motorists wearing helmets, it has been suggested in all seriousness at least in Australia for the very reasons you cited. I remember watching a segment on A Current Affair or similar show discussing the pros and cons of car drivers and passengers wearing helmets and the likely reduction in head injuries and deaths as a result.

 

[cromagnon]

There's a strong dude I see around every now and then he looks in his late thirties, shaved legs, deep tan absolutely FLIES along seems effortless and I have to say he looks cooller than everyone else in his retro cycling cap. Lets face it, it's hard to look stylish with a block of polestyrene on your head.

 

[philcrisp]

I am not sure why you have such a bee in your bonnet about this one. If you look at the poll, over 70% of respondents voluntarily wear a helmet despite it not being compulsory. You don't have to wear a helmet, but you are not going to convince to 70% + of respondents to not wear a helmet because you disagree with compulsory helmet laws in some countries.

As for the casualty rates, plenty of the papers I listed at the start of this thread showed significant reductions in head and facial injuries with helmet use. In regards to motorists wearing helmets, it has been suggested in all seriousness at least in Australia for the very reasons you cited. I remember watching a segment on A Current Affair or similar show discussing the pros and cons of car drivers and passengers wearing helmets and the likely reduction in head injuries and deaths as a result.

I wasn't aware that helmet use had been suggested for motorists had been suggested in Australia, although I've driven in NSW and spoken to a local policemen which gave me a rather jaundiced view of the locals driving standards.

I am, just, old enough to have been subjected to class punishment at school. Like I said earlier, I've been involved in driver education for long enough to know that most "responsible" road users' behaviours falls a very long way short of what should be expected. The creeping acceptance and promotion of an unproven saftey aids while ignoring behavioural issues seems to me to be exactly the wrong way to go about things. In cyclists' case it appears that we are being asked to take responsibility for one hundred years of offical neglect of our saftey.

I will also repeat that the studies used to promote helmet use are at best suggestive and open to counfounding variables and not one of them refers to the casualty rate (usually defined in deaths and serious injuries per kilometre) which takes into account the likelyhood of an accident as well as the outcome of it.

Lastly given my day job I am very aware of how easy legislation in this area is to pass without any thought for the consequences. Local behavioural patterns aren't that disimilar to Australian patterns. How long did it take the number of Australians riding to work to recover after compulsion?

If I care about the future of cycling then I think I should be trying to persuade my fellow cyclists to stop accepting useless saftey aids before they are foisted on all of us in lieu of public policy likely to be effective.

 

[Ninety5rpm]

Not sure about the stats, but drivers in France are extremely courteous to cyclists. I was cycling in Lyon earlier this year and cyclists have right of way on the roads at all times! It is like a cycling utopia over there. I would still wear a helmet because, well, accidents happen. But if there was a place where I would consider not wearing a helmet, it'd be France!

Even if you were guaranteed to never be hit by a car, the reasons to wear a helmet would almost be the same, since most bike crashes do not involve motor vehicles. The helmet is there to protect your head in a fall against the pavement.

 

[Ninety5rpm]

The creeping acceptance and promotion of an unproven saftey aids while ignoring behavioural issues seems to me to be exactly the wrong way to go about things.

Good point.

In cyclists' case it appears that we are being asked to take responsibility for one hundred years of offical neglect of our saftey.

Defensive driving principles have been known and taught for decades. If you follow the rules and properly watch out for the ones who aren't, the probability of being involved in a crash quickly approaches negligibility, practically speaking.

It's the cyclist's behavior that almost solely determines his safety. The behavior of others is, practically speaking, a given over which we effectively have no control or even influence. Even if we could somehow miraculously improve the behavior of 10% of the drivers by 10%, which would be a monumental feat, the effect on any given cyclist's safety would be nil. At the same time, a cyclist can probably improve his safety by an order of magnitude (perhaps even two), simply by learning, and adopting as habits, the best practices of safe traffic cycling.

When all is said and done, bicyclist safety, even in traffic, is all about bicyclist behavior, period.

 

[philcrisp]

Even if you were guaranteed to never be hit by a car, the reasons to wear a helmet would almost be the same, since most bike crashes do not involve motor vehicles. The helmet is there to protect your head in a fall against the pavement.

I agree that most bike crashes are single vehicle but, outside racing, causing permanent damage usually requires automotive assistance. See my comments about the forces involved. I would also be doubtful that the tested crash is one that occurs all that often. Has anyone actually hit their head having the timber moment at traffic lights?

Defensive driving principles have been known and taught for decades. If you follow the rules and properly watch out for the ones who aren't, the probability of being involved in a crash quickly approaches negligibility, practically speaking.

I'd agree. I rate my driving/riding/walking on my perception of everyone else's behaviour, if I'm surrounded by idiots, it's me at fault. However in the UK the teaching of defensive driving has historically been poor and soon forgotten. However if anyone else wants to talk about this I'll start another thread. Is John Franklin a member of this Forum?

When all is said and done, bicyclist safety, even in traffic, is all about bicyclist behavior, period.

This is a good way of staying alive as an individual but I think it's an ineffective way to get other road users to treat us better as group.

 

[Ninety5rpm]

Is John Franklin a member of this Forum?

I don't think so.

This is a good way of staying alive as an individual but I think it's an ineffective way to get other road users to treat us better as group.

Road users don't treat us as a group - each of them treats us one at a time, and nothing affects how I'm treated more than my behavior. There is no other factor that I can think of that comes in second place, much less a close second.

If you exude knowledge, respect, cooperation and confidence while you're out there, by and large you are treated accordingly, even by those who might turn on the next street, encounter someone doing something goofy like desperately trying to share a lane that is too narrow for sharing, and will mash down on the horn out of frustration.

There are exceptions, to be sure. But what we can do is reduce the incidence of "negative encounters" from a few a day or per week, to just a few per year. That is, you can make it so rare through your own behavior, that you end up with little or nothing to complain about. That's the goal.

See the crazy motorists thread for more on this topic.

 

[philcrisp]

I'll do that

 

[elapid]

The creeping acceptance and promotion of an unproven saftey aids while ignoring behavioural issues seems to me to be exactly the wrong way to go about things.

I will also repeat that the studies used to promote helmet use are at best suggestive and open to counfounding variables and not one of them refers to the casualty rate (usually defined in deaths and serious injuries per kilometre) which takes into account the likelyhood of an accident as well as the outcome of it.

If I care about the future of cycling then I think I should be trying to persuade my fellow cyclists to stop accepting useless saftey aids before they are foisted on all of us in lieu of public policy likely to be effective.

I agree with you and Ninety5rpm in that the manner we ride on the roads is very important. I have only been hit twice in my 25 years of riding and commuting, and I think this is mostly because of the way I ride on the roads. But I still maintain that it does not matter how safely you ride on the road there will always be times when you are not in control of the environment around you. This may be because of a mistake on our part (momentary inattention, overestimating your abilities or timing, etc) or because of the actions of someone else. And it is in these times that a helmet may make all the difference.

I totally disagree with the assertion that helmets are "useless safety aids". I think it is irresponsible to suggest that helmets are useless when there is no proof of this, not even flawed studies, and plenty of objective and subjective evidence to prove the opposite. We have previously discussed the numerous papers which have been published regarding bicycle injuries and helmet use. While a paper may not have been published specifically addressing all the nuances that you want, and nearly all papers regardless of the topic have flaws, there are many (ie, hundreds) showing the incidences of facial and head injuries with and without helmets. I have not found a study (not an opinion piece) which showed helmets were either useless or harmful. Please correct me if I am wrong. If you truly think that helmets are a useless safety aid and want to prove it, then maybe you should conduct the study that you so strongly desire. If you cannot, then maybe you should just state your position rather than making irresponsible and patently false claims.

 

[usedtobefast]

I agree with you and Ninety5rpm in that the manner we ride on the roads is very important. I have only been hit twice in my 25 years of riding and commuting, and I think this is mostly because of the way I ride on the roads. But I still maintain that it does not matter how safely you ride on the road there will always be times when you are not in control of the environment around you. This may be because of a mistake on our part (momentary inattention, overestimating your abilities or timing, etc) or because of the actions of someone else. And it is in these times that a helmet may make all the difference.

I totally disagree with the assertion that helmets are "useless safety aids". I think it is irresponsible to suggest that helmets are useless when there is no proof of this, not even flawed studies, and plenty of objective and subjective evidence to prove the opposite. We have previously discussed the numerous papers which have been published regarding bicycle injuries and helmet use. While a paper may not have been published specifically addressing all the nuances that you want, and nearly all papers regardless of the topic have flaws, there are many (ie, hundreds) showing the incidences of facial and head injuries with and without helmets. I have not found a study (not an opinion piece) which showed helmets were either useless or harmful. Please correct me if I am wrong. If you truly think that helmets are a useless safety aid and want to prove it, then maybe you should conduct the study that you so strongly desire. If you cannot, then maybe you should just state your position rather than making irresponsible and patently false claims.

it only takes one time, and you can be in a chair, or worse. i prefer not seeing someones brains splattered across the road. it makes for a bad day.
do it for the rest of us.

 

[philcrisp]

I think it is irresponsible to suggest that helmets are useless when there is no proof of this, not even flawed studies, and plenty of objective and subjective evidence to prove the opposite.

I have not found a study (not an opinion piece) which showed helmets were either useless or harmful. Please correct me if I am wrong.

Try

Cycle helmets and road casualties in the UK Hewson PJ. Traffic Injury Prevention, 2005;6(2):127-134

Reducing bicycle accidents: A reevaluation of the impacts of the CPSC bicycle standard and helmet use. Rodgers, GB. J. Product Liability. Vol. 11, no. 4, pp. 307–317. 1988.

A rational approach to pedal cyclist head protection, Depreitere B. Catholic University of Leuven. 2004.

Specific patterns of bicycle accident injuries - an analysis of correlation between level of head trauma and trauma mechanism Möllman FT, Rieger B, Wassmann H. DGNC Köln, 2004.

Trends in cycle injury in new zealand under voluntary helmet use, Scuffham PA, Langley JD. Accident Analysis & Prevention: 1997;29(1):1-9

While I appreciate that there is a lot of noise from amateurs in the the two pages below, there is comment broadly agreeing with each of us from professionals on both

http://www.bmj.com/cgi/eletters/332/7543/722-a#130740 (Robinson's originl article here (http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1410897&blobtype=pdf) and

http://www.bmj.com/cgi/eletters/332/7543/725 See above for relevant article

http://policy.rutgers.edu/faculty/pucher/Irresistible.pdf See p16, they've done rather better at improving cycling safter than the English speaking world, why are they so opposed to promoting helmet use?

 

[Ninety5rpm]

I agree with you and Ninety5rpm in that the manner we ride on the roads is very important. I have only been hit twice in my 25 years of riding and commuting, and I think this is mostly because of the way I ride on the roads. But I still maintain that it does not matter how safely you ride on the road there will always be times when you are not in control of the environment around you. This may be because of a mistake on our part (momentary inattention, overestimating your abilities or timing, etc) or because of the actions of someone else. And it is in these times that a helmet may make all the difference.

I totally disagree with the assertion that helmets are "useless safety aids". I think it is irresponsible to suggest that helmets are useless when there is no proof of this, not even flawed studies, and plenty of objective and subjective evidence to prove the opposite. We have previously discussed the numerous papers which have been published regarding bicycle injuries and helmet use. While a paper may not have been published specifically addressing all the nuances that you want, and nearly all papers regardless of the topic have flaws, there are many (ie, hundreds) showing the incidences of facial and head injuries with and without helmets. I have not found a study (not an opinion piece) which showed helmets were either useless or harmful. Please correct me if I am wrong. If you truly think that helmets are a useless safety aid and want to prove it, then maybe you should conduct the study that you so strongly desire. If you cannot, then maybe you should just state your position rather than making irresponsible and patently false claims.

Well said.

For a diagram that illustrates this, see this slide:

http://www.cyclistview.com/ITC-Intro/slide12e.htm

This slide shows the five layers of safety for a traffic cyclist. Note that the order is important. The front line defense is "bike control" - the last line of defense is the helmet ("injury reduction").

Also look at the earlier slides that show the components of each layer. For example, layer 4 is "hazard avoidance" and that is made up of
- know common mistakes
- situational awareness
- emergency maneuvers

http://www.cyclistview.com/ITC-Intro/slide12d.htm

To see all components of each of the 5 layers, start on the first slide (bike control) and click "Next" at the bottom of each slide to get to the next one...

http://www.cyclistview.com/ITC-Intro/slide12a.htm

This is the best material on the web regarding bicycle safety, so far as I know. And yeah, I've seen bicyclesafe.com.

 

[elapid]

I have only read the abstracts of these papers, but:

Cycle helmets and road casualties in the UK Hewson PJ. Traffic Injury Prevention, 2005;6(2):127-134

This paper looks at overall injuries, not specifically head injuries. Helmets will not protect against anything other than head and facial injuries. Chest, spinal, abdominal, arm and limb injuries will happen regardless of whether or not we wear a helmet.

Reducing bicycle accidents: A reevaluation of the impacts of the CPSC bicycle standard and helmet use. Rodgers, GB. J. Product Liability. Vol. 11, no. 4, pp. 307–317. 1988.

A rational approach to pedal cyclist head protection, Depreitere B. Catholic University of Leuven. 2004.

Specific patterns of bicycle accident injuries - an analysis of correlation between level of head trauma and trauma mechanism Möllman FT, Rieger B, Wassmann H. DGNC Köln, 2004.

I do not have access to the abstract or text of these papers. Can you provide me with a link or a copy?

Trends in cycle injury in new zealand under voluntary helmet use, Scuffham PA, Langley JD. Accident Analysis & Prevention: 1997;29(1):1-9

This paper is looking at head injury rates in three age groups over a 12 year period (1980-1992) when helmet use was not compulsory in NZ. The authors do not give the numbers involved, but the authors found no decline in head injury rates. However, interestingly, the same first author also found a 19% reduction in head injury rates in the first three years following the introduction of compulsory helmet legislation in NZ, suggesting that the sample numbers involved in each group studied in the original paper may have been too small to detect a significant difference. This is highlighted by the fact that only 20% of adults and 40% of children voluntarily wore helmets in NZ in 1989, so an increase of 39% of adults wearing helmets from 1980 to 1992 is not a very high number when starting off at such a low number to begin with.

http://www.ncbi.nlm.nih.gov/pubmed/10868759?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmed

This second study was further supported the study below, again from NZ, which showed compulsory helmet use resulted in a significant 10.2%, 5.3% and 3.2% reduction in non-vehicular related head injuries in primary school children, secondary school children and adults respectively; and a significant 3.6% reduction in vehicular related head injuries.

http://www.ncbi.nlm.nih.gov/pubmed/10487351?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=3&log$=relatedarticles&logdbfrom=pubmed

While I appreciate that there is a lot of noise from amateurs in the the two pages below, there is comment broadly agreeing with each of us from professionals on both

http://www.bmj.com/cgi/eletters/332/7543/722-a#130740 (Robinson's originl article here (http://www.pubmedcentral.nih.gov/picrender.fcgi?artid=1410897&blobtype=pdf) and

http://www.bmj.com/cgi/eletters/332/7543/725 See above for relevant article

The original paper is interesting in the tack that it takes. It is more confounding than any other paper I've read on helmet use and cycling. The author is incorrect regarding the statistics for NZ (see above papers) and then writes off decreases in head injury rates in cyclists in Australia following compulsory helmet legislation because either there were less cyclists or because there was a similar decline in head injury rates in pedestrians and motorists.

See above for relevant article

http://policy.rutgers.edu/faculty/pucher/Irresistible.pdf See p16, they've done rather better at improving cycling safter than the English speaking world, why are they so opposed to promoting helmet use?

Great reference. This goes back to a topic near and dear to me - the lack of cycling infrastructure in countries like Australia, USA and Canada. The Netherlands, Denmark, Germany and most European countries I have visited have far, far superior infrastructure and this makes cycling safer and more popular. Bicycles in many of these countries are utilitarian and used for commuting, shopping, errands, social outings etc. All low speed and in a far more controlled environment than cycling in Australia, USA and Canada where bikes are more often than not used to go fast (training, racing) on busy roads with fast and high traffic volume. If there were more cycling specific paths separate from traffic, then I too would consider not wearing a helmet. But this is not the case in countries like Australia, NZ, USA and Canada.

So, I am sorry but you can only show me one verifiable paper which shows no decline in head injuries with helmet use, but this paper is based on voluntary helmet use (which you are not opposed to) and subsequent papers by the same and other authors in the same country found significant reductions in head injuries following both non-vehicular and vehicular cycling accidents across all age groups following the introduction of compulsory helmet laws.

 

[mherm79]

i wear one for two reasons

1. its the law and don't want to give drivers the impression i'm out there to break the road rules,

2. if i headb*tt the ground i would to be wearing a specially designed 'hat' at the time

 

[philcrisp]

First I apolgoise for substituting the URL of one of your links for the paper's title, it made referring to it more than once much easier.

I have only read the abstracts of these papers, but:

Cycle helmets and road casualties in the UK Hewson PJ. Traffic Injury Prevention, 2005;6(2):127-134

This paper looks at overall injuries, not specifically head injuries. Helmets will not protect against anything other than head and facial injuries. Chest, spinal, abdominal, arm and limb injuries will happen regardless of whether or not we wear a helmet.

Full text here http://cycle-helmets.com/P563.pdf

I do not have access to the abstract or text of these papers. Can you provide me with a link or a copy?

A rational approach to pedal cyclist head protection, Depreitere B. Catholic University of Leuven. 2004. http://www.kuleuven.be/doctoraatsverdediging/0304/93e.pdf

Specific patterns of bicycle accident injuries - an analysis of correlation tween level of head trauma and trauma mechanism Möllman FT, Rieger B, Wassmann H. DGNC Köln, 2004. http://www.egms.de/en/meetings/dgnc2004/04dgnc0134.shtml

Trends in cycle injury in new zealand under voluntary helmet use, Scuffham PA, Langley JD. Accident Analysis & Prevention: 1997;29(1):1-9

This paper is looking at head injury rates in three age groups over a 12 year period (1980-1992) when helmet use was not compulsory in NZ. The authors do not give the numbers involved, but the authors found no decline in head injury rates. However, interestingly, the same first author also found a 19% reduction in head injury rates in the first three years following the introduction of compulsory helmet legislation in NZ, suggesting that the sample numbers involved in each group studied in the original paper may have been too small to detect a significant difference. This is highlighted by the fact that only 20% of adults and 40% of children voluntarily wore helmets in NZ in 1989, so an increase of 39% of adults wearing helmets from 1980 to 1992 is not a very high number when starting off at such a low number to begin with.

http://www.ncbi.nlm.nih.gov/pubmed/10868759?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedarticles&logdbfrom=pubmed

This second study was further supported the study below, again from NZ, which showed compulsory helmet use resulted in a significant 10.2%, 5.3% and 3.2% reduction in non-vehicular related head injuries in primary school children, secondary school children and adults respectively; and a significant 3.6% reduction in vehicular related head injuries.

Povey, L.J., Frith, W.J., Graham, P.G., 1999. Cycle helmet effectiveness in New Zealand. Accid. Anal. Prev. 31, 763-770.

Second study, did you notice that the authors worked for a goverment agency? I'm not that familiar with NZ bureaucracy, is the LTSA responsible for the helmet law? I note their findings but the LTSA have since published figures for bicycle use in NZ showing a long term decline. Official numbers here http://cycle-helmets.com/nz-ltsa-2006.pdf

The original paper is interesting in the tack that it takes. It is more confounding than any other paper I've read on helmet use and cycling. The author is incorrect regarding the statistics for NZ (see above papers) and then writes off decreases in head injury rates in cyclists in Australia following compulsory helmet legislation because either there were less cyclists or because there was a similar decline in head injury rates in pedestrians and motorists.

Robinson's data for NZ was from Povey et al 1999, which you refered to above.

In respect of Australia, wasn't that the point? The helmet laws are claimed to have coincided with a reduction in cycling which on its own should have been expected to have produced a reduction in head injuries assuming a constant ksi per km rate. In addition the laws were introduced in tandem with measures that had been shown to be effective at reducing collisions in all road users in other jurisdictions, the helmet law being the only novelty. Therefore how can an increased proportion of cyclists wearing helmets be said to be effective if there casualty rate does not decline faster than other groups?