Explaining helmets to the cops

September 20, 2012 at 09:30 | Posted in bicycles | 9 Comments

I’m sorry, dear reader, I am compelled to write about helmets again. This is because I received yet another ticket the other day for the heinous crime of riding bicycle whilst wearing an ordinary hat.  In Australia you have to wear a special polystyrene hat, of course, or face criminal charges.

Anyway, the conversation went along the usual lines, except that when I spent a few minutes explaining some of my reasoning for not wearing a helmet one of the officers actually seemed quite interested, and asked me to send him information.

‘Whatever you’ve got,’ he said airily, ‘Email it to me – I’ve got an eighty megabyte inbox!’

My first thought was that I could fill that up a few times over with all the research papers and such that I have, and I was at first tempted to do just that, in a kind of ‘ya boo sucks to you’ kind of way. However, on reflection, I decided to be a little more grown up. The guy was interested, so I should help him understand the issues better.

Accordingly, I put together a series of emails on some of the key topics, and attached some relevant reading. On the whole I tried to stay away from heavily technical papers, instead opting for more useful summaries or articles.

The text of them is reproduced below. They aren’t great (I wrote them quite quickly in snatched moments), and I haven’t edited or amended them. What was most interesting, though, was his reply. If you want to see that, just skip down to the bottom of the article…


Dear Constable XXX,

 Many thanks for your professional and courteous conduct last week when you stopped me whilst riding my bicycle over Anzac Bridge; you will remember that I was not wearing a helmet. I did briefly express some of my reasons at the time; I am pleased you were interested; it is great when people – especially those in positions of authority such as yourself – take an interest in these matters.

 The law, of course, is the law. The data show that the law has been counter-productive, has not resulted in a lower accident rate for cyclists and that wearing a helmet actually, at an individual level, increases the risk of accident and injury. This alone is not a defence for breaking the law; however. I have, along with several others, challenged this law via the courts using a technical legal argument based on the NSW common law defence of ‘necessity’; this in essence allows that breaking the law can be excused in certain conditions where following the law would cause danger. Such cases have invariably led to section 10 dismissals, along with comments from the presiding judge / magistrate to the effect that the law need to be changed.

 To date, however, lobbying politicians on this issue has not been effective. Some progress is being made, but it’s a low-priority matter for politicians, and generally they are not interested in taking time to understand the evidence.

 In the meantime, I continue to ride a bike without a helmet, to protect my health, and accept the consequences of my actions in terms of any fines I may incur.

 I have a large number of studies and papers I can share with you. To date there are around 80 published research papers from peer-reviewed scientific journals that raise doubts as to the efficacy of helmets and helmet laws. Each paper is between 5 and 30 pages long. I have read all of them, but I am guessing you do not have the time nor the inclination to read around 800 pages of scientific evidence! As such, I will send you some of the key papers and information, focussing on the main issues and trying to choose papers that are not overly-technical.

 As a starting point, I attach a paper written by Dr Dorothy Robinson, a senior statistician at the University of New England, NSW. Dr Robinson has published widely on the topic of bicycle helmets. The attached paper is not from a peer-reviewed journal, but rather is a recent review of the evidence and factors pertinent to bicycle helmets; as such it serves as quite a useful introduction to the topic. It’s also not too technical to read.

 You’ll see if covers the evidence for a number of points:

  •  Evidence that the introduction of mandatory helmet laws (and the associated increase in helmet wearing) did not result in a drop in the rate of cyclist head injuries
  • Effects of helmet laws on cycling participation – cycling levels dropped markedly when the law was introduced
  • Evidence that the health benefits of riding a bike far outweigh the risks of head injury (even with no helmet)
  • That the drop in cyclist numbers following the helmet law introduction made cycling conditions more dangerous in Australia
  • Risk compensation; the evidence that cyclists wearing helmets tend to ride faster and take more risks
  •  Cost-benefit analyses of the helmet law showing it is actually costing money in health terms
  • The mechanisms of brain injury; worrying evidence that helmets amplify the forces that cause the most serious brain injuries
  • The overall effect; that helmet laws and helmet wearing has actually increased the risk per cyclist of riding  a bike in Australia

 There are also many notes about the data, and references for further reading. As I mentioned, I will send you some further papers in due course. However, in the meantime if you have any questions, please don’t hesitate to email me, or call me.


Dear Constable XXX,

 Further to my earlier email, I am pleased to attached another paper which may be of interest. Again, rather than a scientific paper it is an extract form a book, which makes it a little easier to read. The (Australian) author, Bill Curnow, is a world authority on the effectiveness of bicycle helmets particularly as they relate to brain injury. He has published many papers on this subject, and has appeared on two occasions as a expert witness in the NSW court – on both occasions his evidence was upheld.

 The key point of this paper is the mechanism of brain injury. Curnow illustrates that it is not, as is commonly believed, caused by a straight blow to the head, but rather by rotational forces which cause the brain to suffer shear strain as it rotates in the skull. In essence, receiving a sharp rotation to the head is more dangerous than a direct blow with no rotational element.

 The problem here is that bicycle helmets are not designed to prevent these kind of forces. In fact, they tend to amplify them – they make the head circumference bigger, which increases the rotational forces of an oblique blow (much in the way a bigger cog creates greater force on the wheel when you change gear on a bike).

 This is a very important point, as it speaks directly to the danger a cyclist places themselves in if they choose to wear a helmet. If you are unlucky enough to fall off your bike whilst wearing  a helmet, the helmet tend to increase the rotational forces on the head, which in turn makes the most serious kind of brain injury (called ‘diffuse axional injury’) more likely. This fact may, in part, answer the question posed by the first paper I sent you – why did head injury rates for cyclists not go down when the helmet law was introduced?

 Kind regards,


Dear Constable XXX,

 Further to my previous emails, attached is another paper which I hope is of interest. This one refers to ‘risk compensation’.

 Risk compensation is a well-studied phenomenon by which people tend to increase their risk-taking behaviour in the presence of safety equipment. This is of course also well known anecdotally; the ‘volvo driver’ who drives more aggressively because he as crumple zones and safety systems, for example. However, the scientific literature on this is widespread; there are many fascinating case studies on things as diverse as anti-lock brakes to child-proof drug bottles that demonstrate that people tend compensate for the presence of safety systems by taking more risks – meaning that in many cases the expected benefit from the safety intervention evaporates because of the associated behaviour change. (This is why you don’t get an insurance discount for having anti-lock brakes – the insurers know that cars with anti-lock brakes have just as many accidents as those without, even though you’d expect them to have less given that they are easier to control under emergency braking and tend to have shorter stopping distances).

 Risk compensation has also been observed in bicycle helmet use. The attached research shows that people tend to ride faster when wearing a helmet. The corollary of this is that you are more likely to have an accident if you wear a helmet – as speed and lack of caution are obvious factors in accident incidence and severity. Coupled with the previous paper on brain injury, this paints a stark picture – if you wear a helmet, you are more likely to have an accident, and that accident is more likely to result in serious brain injury. Scary stuff indeed.

 Interestingly this is what got me started investigating and reading about helmets. One morning on the way to work I forgot my helmet (I used to wear one), and was amazed to find I rode much more cautiously. It was quite an astonishing thing; I particularly noticed it on the ramp where you were positioned when we met; with a helmet on I used to scoot down there really fast (unless, of course, there were pedestrians on the path). On that day when I forgot my helmet I felt much more vulnerable, and rode down with my hands on the brakes.

 It’s an interesting experiment – try going for a ride without your helmet, and see if you ride differently. (Although I perhaps shouldn’t be inciting a Police Officer to break the law!! Perhaps find some private land to conduct your experiment…) I know that I do; I am now a much more cautious cyclist. In the two years  I wore a helmet I had three of four accidents. In the three years since I stopped, I have not had a single one – and I have far fewer ‘near misses’ too.

 Kind regards,


Dear Constable XXX,

 Further to my previous emails, attached is another paper which I hope is of interest. This one refers to ‘safety in numbers’.

 ‘Safety in numbers’ is a well-established principle when considering the safety of vulnerable road users (pedestrians and cyclists). Essentially, it shows that the more people there are cycling or walking, the safer it becomes for everyone.

 This is of course common sense. The primary danger to cyclists and pedestrians is from motor vehicles. Given this, the more cyclists there are on the roads:

  • Motorists will be expecting cyclists, be more used to looking out for them
  • Motorists are themselves more likely to be cyclists, and therefore aware of the needs of cyclists and how to drive appropriately around them

 The attached paper illustrates this, and shows how much safer our roads would be if there were more cyclists. Unfortunately, our helmet laws have had a significant and detrimental effect on cycling participation, as you would have seen in the first paper I sent through – around 40% of cyclist stopped riding when the law came in. This had the unfortunate effect of making cycling more dangerous – as the corollary of the ‘safety in numbers’ effect is that if rider number drops, the dangers of riding increase.

 Whilst I realise that you have a job to do, and I hope you also realise that I have no argument with you or you colleagues (the law is the law), you might reflect on the fact that giving cyclists tickets for minor matters such as helmets, bells and lights tends to discourage people from cycling – which actually makes cycling more dangerous for those that remain. Hardly the outcome I am sure you are trying to achieve!

 Kind regards,


Dear Constable XXX,

I hope you have had some time to look at the papers I sent to you; I am trying to send them in a logical order, so it’s probably best to start reading from the first mail i sent, rather than jumping in the middle!

I have already sent you some information about risk compensation; the tendency for people to take more risks when safety measures are put in place. However, there is also another aspect to risk compensation; this is called ‘3rd party risk compensation’. This is when a third party takes less care to prevent an accident or injury to another person because that person is deemed to be ‘low risk’ – for example they are wearing safety gear. Examples of this abound in sport – I’m sure you would be less likely to bowl a fast bouncer delivery to a batsman in a Sunday cricket game if they were not wearing a helmet then if they were, for example, as your fear that you might injure the poor batsman with such a delivery would be reduced if he was wearing a helmet.

This effect is also seen with bicycle helmets and motorists. Research has demonstrated that motorists tend to leave less space when overtaking helmeted cyclists than when overtaking bare headed ones. This is an extraordinary result, but one entirely predicted by risk compensation models; motorists (subconsciously) see helmeted cyclists as ‘less vulnerable’, and therefore are less cautious when overtaking them.

This adds further to the picture. We now have a situation where if I wear a helmet, I am more likely to have an accident because of changes to my own behaviour, more likely to be hit by a car because of changes to motorist behaviour – and if such an accident were to occur, be more likely to receive a serious brain injury. This is not an encouraging picture.

The attached paper was written by Dr Ian Walker, who conducted the research. It is not the original paper (which is rather long and technical), but a briefing paper which I hope is easier to read. This research was conducted in the UK, but has not been replicated here in Australia. This is a pity (I generally try to use Australian research using Australian data, as it is then clearly applicable to my situation), but in the absence of any local research into this particular subject this is the best knowledge we have.

Anecdotally this does seem to be true in Sydney, though. Several women cyclists have commented in online discussion forums that car drivers give them more space when they are dressed in casual clothes and a skirt, compared to cycling gear. Similar effects have been reported by bare-headed cyclists – and certainly since I stopped wearing a helmet I have experienced fewer ‘near misses’ than when I used to wear one.

Kind regards,


Dear Constable XXX,

You will have seen from the first paper I sent you that the introduction of the bicycle helmet law had a dramatic effect on cycling participation in Australia – cycling levels dropped around 40%. Leaving aside the fact that this is not a good thing (as cycling has many benefits), this drop in participation also made cycling more dangerous, due to the ‘Safety in Numbers’ effect that you will also have read about.

However, some people have suggested that this drop in participation was temporary, and that cycling levels are now rising, and the helmets are no longer a discouragement to cycling. These anecdotal observations, however, do not gel with the facts.

Attached are two papers which look at this; both by Professor Chris Rissel of the University of Sydney. The first is a comparison of cycling levels from 1985 (prior to the helmet law) and 2011. It shows that whilst the total number of cyclists is indeed rising, it is rising more slowly than population growth. in other words, there are proportionately less people cycling today than in 1985. Clearly cycling has not recovered to pre-helmet law levels. (This is the ‘wtpp18.3′ attachment; the specific paper is on page 5.)

But are helmets still discouraging people? Well, Prof Rissel did more research to look at that – a telephone survey in Sydney that asked non-cyclists the reasons why they did not cycle. One in five people said they would ether start riding or ride their bike more if they did not have to wear a helmet. He calculated that cycling levels in Sydney could double over 5 years if the helmet law was revoked (see the ‘Rissel’ attachment). This would have a very positive effect on cycling safety, as the ‘safety in numbers’ research indicates. It seems almost paradoxical that removing the requirement to wear a helmet would improve cyclist safety, but the evidence is quite clear – it is just a pity that so few people (our politicians amongst them) take the time to understand the issue.


And here is his response:

Dear Chillikebab,

Thank you for your emails, it does raise some interesting information relating to the use of bicycle helmets, however the “Law” is in fact, “The Law”.

 Simply attending court of over this matter will not change the law, only leaving you liable for more loss of time and even higher penalties (Remember this fine may only be $66.00, however the court can impose a penalty up to $2200).

 The best advice I can give (Believe me, I know some pretty powerful people and seek the advise their throughout my career), pursue it through the government, and keep pursuing. I strongly recommend you approach your Local member of Parliament or State Member to have this law reviewed, as I am in a position of Authority, I do not make the laws, however enforce them.

 You might even want to send it to Clover Moore’s office for review, as she is really pushing the use of bicycles in the City of Sydney area, I found the team at Clover’s office very understanding and willing to listen to anyone with a strong case and backed up evidence to support their cause.

 Until this law is lifted, police will have no choice but to enforce it, on another note, you may want to talk to the spokesman for Bicycle NSW to launch some campaign.

 On a personal note, I do believe it should be optional to wear a helmet above the age of 16 years, as children still going through their growing stages of life, it could in fact save their lives. I know the helmet saved me when I was in my teens, I hit the pavement travelling at 30 km/h when a car door opened in front of me, my helmet was cracked but my head was not!


Senior Constable | New South Wales Police Force
Traffic Services
City Central Police Station
192-196 Day Street Sydney NSW 2000


So there you have it. A police officer who thinks bicycle helmet laws should be scrapped for adults. I daresay he’s as bored standing around giving out helmet tickets all morning as i am receiving them..!




I have had many requests to add in the papers that I sent to the Police Officer, so I have updated this post to include them. They are all in the public domain, and / or have been supplied to me by the authors with permission to distribute. However, if there are any copyright issues or the owners / authors would prefer me not to link to them here, please contact me and I will remove them.

The other interesting thing is that I have yet to receive a ticket relating to this occasion, and given it was several weeks ago it seems likely that I am not now going to receive one. So perhaps it is possible to talk yourself out of a ticket!


September 12, 2012 at 21:34 | Posted in bicycles | 1 Comment
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This was the view from Iron Cove Bridge tonight as I rode home. Very pretty. And on the other side of the bridge the light was glinting off the buildings in the distance, burnishing them with gold. All rather spectacular. (I took a picture of the buildings too, but it came out less well).

Of course, the motorists driving by in their cars missed all of this; all they can see is a monotonous concrete barrier and the lines of cars in front of them stretching through interminable traffic lights. I love the way cycling actually connects you with the city; fast enough that you can get about to different places but slow enough that you can stop and stare. Seeing a city through a windscreen is an anonymous, souless experience.

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