I was just in LA. I was surprised and pleased when a good friend of mine mentioned this brilliant new transportation scheme the city had developed. Basically, with sponsorship from a few businesses the city had placed hundreds of electric cars at street-side parking-spots (where the car batteries recharged) throughout the most frequented neighborhoods. The idea was that anyone (tourist or city-dweller) could rent the electric car by the half-hour, paying by card at a nearby pay station. Then the renter could bring the electric car back to any of the city parking spots by the set time. What was even more convenient was that city-dwellers could get an “LA-Car Card” by paying a nominal fee that would allow them to take out electric cars for up to a half hour at a time for free! Environmental AND convenient! So of course I went straight to the nearest electric car parking-spot, paid the fee, and was soon zooming about the streets of LA. I had never driven an electric car before, so it felt a bit odd, but I was so excited by the new car scheme that I didn’t let it bother me. Everything was grand until a reckless driver ran a red light in front of me and nearly took me off the road. Thankfully it was only nearly. But with that close-call, I realized that the reason the car had felt a bit odd is that the car had NO SEATBELTS! That’s right: no seatbelts. What would have happened if I had been in a car accident?
These electric cars were environmentally friendly, yes. Super-convenient, yes. But wasn’t it irresponsible for the city to encourage needless risk-taking (and traumatic brain injury) by providing this transport without the most basic safety feature?? For worried as I was about my safety in not having a seat-belt (and I would never drive my own car without my seat-belt), I found myself renting and driving the cars for the rest of my stay just because they were so darn convenient. I oscillated between decrying the city’s irresponsible behavior and applauding their creation of such a convenient scheme. Which was the proper stance? And was there a rational reason why these cars did not have seat-belts??
In reality, there isn’t a transport scheme in LA that provides electric cars with no seatbelts. The transport scheme is in Dublin and London that provides bicycles with no helmets. But the rest of the story, the mechanics, and the ethical dilemma are the same. City-sponsored transport-schemes in these cities provide bicycles to city-dwellers and tourists without the option of a helmet. Environmentally friendly, yes. Super-convenient, yes. But definitely a public health hazard.
So should we applaud the city for its convenient scheme? Or cry out that it is encouraging its citizens and visitors to take needless risks? Traumatic brain injury, after all, is no joke.
In a real way, the actions of a city and its governing bodies make statements. By providing these bicycles without the most basic safety measure, the city makes a statement that bicycle safety is not important, a statement which seems both irresponsible and immoral.
But it is more than the statement. After all, who will use these bicycles most often? Those without bicycles of their own. In other words, those with less bicycle experience, the very ones who should be taking more (not less) safety precautions. The very ones more likely to hit the curb and fall into the street; the very ones already at increased risk of sustaining a life altering brain injury. Shouldn’t the city be extra careful to protect these vulnerable people?
What could be the argument against providing helmets with these bicycles? It seems that the only argument could be the one from logistical difficulty or cost. But however costly it would be to install bicycle helmets with these bicycles, it seems like a drop in a bucket compared to the cost of caring for just one person with an (avoidable) traumatic brain injury. In countries with socialized health care systems, moreover, the money ultimately comes from the same place.
Am I missing a good argument against helmets? Perhaps one could make the argument that even if the city provided helmets, most would not wear them. But even if this is the case (and I would be surprised if it were), shouldn’t the city be encouraging safe bicycling by making the option available? A portion of people would, after all, wear the helmets.
I applaud these city-transport schemes for being innovatively convenient and environmentally friendly. But the city, if it is going to provide such a scheme, has a responsibility to make it possible to (and indeed encourage people to) use it safely. In this case, the city has a responsibility to provide helmets.
So should Hertz and Avis provide helmets for car renters? Car occupants suffer the most traumatic head injuries of all road users. Oh, and how about walking tour guides? Pedestrians suffer more head injuries than cyclists.
Where's the ethic in misleading people?
Hi Jeff, thank you for the comment. You raise an interesting set of issues. Namely
1) do commercial companies (hertz and avis) have the same set of responsibilities to minimize this kind of risk of head injury?
2) to what extent should we go to minimize that risk (are seat belts in cars enough or should we wear helmets it cars too?)
3) why do some types of risk taking get more attention than others (cars and cycles vs pedestrians or joggers?)
In terms of where I weigh in, I think that governments have different responsibilities than commercial companies in keeping citizens safe. While helmets in cars may in fact not be a bad idea (race car drivers wear them) I think we could recommend a decent minimum of protection (like seatbelts in cars and helmets for cycles). Finally I broadly agree that the concern we place and precautions we take should mirror the riskiness of the activity; this ranking of course should be evidence based and though I would be surprised to learn that walking has a higher risk of head injury than cycling, I would support more concern for walker safety if this were the case. As we in reality have different intuitions about these different types of transport,my well intentioned misleading of the readers was meant to question these intuitions. I hope I have not offended.
**Sorry, 1) should read " do commercial companies have the same responsibilities as governments to minimize this kind of risk of head injury?"
Head injuries due to motor vehicle accidents are about 4-fold more common than those due to bicycle accidents, but that has nothing to do with Matt's excellent point that governments should not implement bicycle rental programs without requiring the use of helmets (as has been done in L.A., Dublin, and Montreal, for example). The relevant issue is whether cyclists who wear a helmet are more or less likely to suffer traumatic head injuries than other cyclists who don't. As an epidemiologist, I can tell you that there is very strong evidence that bicycle helmets reduce the risk of traumatic brain injury by approximately 74% (see Ref. 1). Not only that, helmet reduce the risk of death (see Ref 2). Here's a quote from one study, which was published in one of the best journals of pediatric medicine: "An average of 247 traumatic brain injury deaths and 140,000 head injuries among children and adolescents younger than 20 years were related to bicycle crashes each year in the United States. As many as 184 deaths and 116,000 head injuries might have been prevented annually if these riders had worn helmets." The protective effects of wearing a helmet while riding a bicycle have been shown in the USA (Ref 2 and Ref 3), France (Ref 4), Germany (Ref 5), Australia (Ref 6), and Singapore (Ref 7), to give some examples. Given the clear clinical and life-saving benefit of helmets, is it ethical for governments to encourage the public to ride bicycles more often without requiring the use of helmets or some other measure to ensure helmet use? It is wonderful that governments are trying to promote physical activity, but without helmets, bicycle rental programs will most likely lead to an increase in otherwise preventable traumatic brain injury and death.
Ref 1: http://www.ncbi.nlm.nih.gov/pubmed/10796827
Ref 2: http://www.ncbi.nlm.nih.gov/pubmed/8909479
Ref 3: http://www.ncbi.nlm.nih.gov/pubmed/8971066
Ref 4: http://www.ncbi.nlm.nih.gov/pubmed/21606469
Ref 5: http://www.ncbi.nlm.nih.gov/pubmed/21161881
Ref 6: http://www.ncbi.nlm.nih.gov/pubmed/17655641
Ref 7: http://www.ncbi.nlm.nih.gov/pubmed/16645687
And yes, Hertz and Avis should require their customers to wear helmets. How hilarious would that look?!
As an epidemiologist, you have looked at all the evidence about helmets haven’t you? Not just the small scale, short term case control studies which have proved wrong so often that no rational person would base policy on them. Most researchers these days discount such research as unreliable unless supported by other data, but in the case of cycle helmets, the other, more reliable data flatly contradicts it. At a population level, all the reliable evidence shows that at best helmets make no difference, and at worst increase the risk.
The initial case for helmets was based on bad science (Thompson, Rivara and Thompson, 1989) which found that helmets prevented 85% of deaths and injuries to cyclists. Unfortunately, its methodology was so bad that some commentators have said that it could be used as an example to students of how not to do research. It compared helmeted children cycling around parks with their parents to unhelmeted children cycling in streets with motor vehicles, and attributed the difference in death and injury rates to the helmets. This research was so bad that it showed that helmets protected elbows and knees. Almost every pro-helmet research paper since has quoted the 85% figure, even though peer review has completely disproved it. Almost all, if not all, research which has found massive benefits from cycle helmets has used methodology which has proved suspect and has been effectively challenged on peer review e.g. case control studies. None of the predicted benefits have been observed at a population level, using methodology which has stood the test of peer review.
So, as an epidemiologist, do you believe the less reliable, frequently disproved research, or do you believe the more reliable research which has not been disproved?
Try looking at http://www.cyclehelmets.org with an open mind.
And the London scheme has proven incredibly safe: it’s been running for about a year and there have been no serious injuries, despite millions of miles being cycled, and other schemes have found the same effect.
The benefits of cycling are so huge that one researcher has said that if it could be bottled, it would be the most popular medicine in the world: regular cyclists live longer, are fitter, healthier and suffer less from all forms of morbidity. The only proven effect of helmet laws and propaganda campaigns is to reduce the number of cyclists, with no improvement in safety. The effect at a population level is therefore negative, and I’m sure that as an epidemiologist, you can appreciate this point.
Have you considered that you might have fallen for the twenty year long propaganda campaign? If you don’t believe that this campaign is real, do some googling and check out the media reports, almost all of which have unashamedly promoted cycle helmets by making cycling appear much more dangerous than it actually is. You might like to look more closely at BBC websites, which has a charter which guarantees balanced reporting: in twenty years of BBC output, I’ve only seen or heard one single report which could be thus described: all the dozens of others were grossly biased e.g. the article in last year’s R4 programme “More or Less” which is supposed to examine the misuse of statistics. For the only time in the programme’s history, it didn’t look at the statistical evidence, and it only interviewed people who were pro-helmet.
You clearly have not read the Thompson et al. article from 1989 (New England Journal of Medicine 320:1361-1367, 1989). They do not make the comparison you suggest, not even close. There are indeed problems with the Thompson et al. study but they are not the one you erroneously cite.
For any epidemiologic study, regardless of the study design (e.g. case-control, cohort, randomized controlled trial, etc.), determining its reliability is a very challenging issue and almost always becomes a matter of opinion. Without careful assessment — let alone without reading the study you criticize — opinions about reliability would be grossly misinformed and biased.
On a related note, I take issue with your general dismissal of case-control studies. They suffer from limitations, as all study designs do, but that does not mean they are inherently wrong or useless. It means they require interpretation in the context of known limitations, i.e. critical appraisal.
That being said, the primary concern with case-control studies is selection bias, a problem stemming from difficulty selecting a control sample that’s derived from the same source population as the cases. So in most scenarios, I would tend to agree that policy should not be made based on findings from case-control studies alone. Fortunately, other approaches have been taken as well (contrary to your claims). See Ref 2, Ref 6, and Ref 7 for some examples. None of these are case-control studies.
Since you have alluded to “long-term, whole population research” several times, perhaps you could provide a reference to the specific article(s) to which you refer? That way other readers can judge their reliability for themselves.
I must move on to other things but will certainly check back in to see how the discussion of Matt’s article evolves (and to obtain a reference or two, ahem). Richard, I wish you the best of luck and safety in the rest of your riding….
——–
Also, the link I provided for Ref 7 (see my previous post) was incorrect. Here is the correct one: http://www.ncbi.nlm.nih.gov/pubmed/16645684
just go to http://cyclehelmets.org/1139.html and read.
Then weep.
Dear Matt, a very interesting story, but it is clear that you know absolutely nothing about cycling, safety, and cycle helmets.
There is only an ethical dilema if two conditions are satisfied: that cycling is dangerous and abnormally likely to cause head injuries, and that cycle helmets prevent death and injury. Since it is demonstrable that neither of these conditions apply, there is no ethical dilema.
Cycling is about as dangerous, or safe, per mile travelled, as walking, so it is not dangerous in the accepted sense, neither is it particularly productive of head injuries. The only thing that has made cycling seem to become more dangerous in the last 20 years is the massive propaganda campaigns to convince the public to wear helmets, all of which grossly over-emphasises the dangers of cycling to make cycle helmets appear a logical choice. On average, regular cyclists, those most exposed to the risk, live two years longer than the general population: it would appear to be more dangerous not to cycle than to cycle. Regular cyclists also suffer less from all forms of illness, and are fitter, healthier and slimmer than most people.
There is no reliable evidence, despite over 20 years of experience of New Zealand and Australia, which shows that cycle helmets reduce risks to cyclists, and there is some research which shows a reduction in safety with helmet wearing. When these laws were introduced, staggering claims were made about their effectiveness, the most frequent being that they would prevent 85% of deaths and injuries to cyclists. The situation with massive rises in helmet wearing due to propaganda campaigns is the same: either no change in risk or a decline.
Your entire article is based on the assumptions that cycling is dangerous and cycle helmets reduce risk, but neither is true. Do you think it's ethical to write such an article, exaggerating the dangers of cycling and detering yet more people from healthy, safe exercise, when you are completely ignorant of the subject?
Actually, there is reliable evidence from Australia showing that cyclists who wear helmets are at lower risk of injury. See this study: http://www.ncbi.nlm.nih.gov/pubmed/17655641.
Do your homework….
And don't make claims, as you say at the end of your post, "when you are completely ignorant of the subject." Your 20 years of experience as a cyclist doesn't make you a safety expert let alone knowledgeable in the subject.
“Actually, there is reliable evidence from Australia showing that cyclists who wear helmets are at lower risk of injury. See this study: http://www.ncbi.nlm.nih.gov/pubmed/17655641.”
Depends on your definition of reliable: this is small scale, short term research, but all the long term, whole population studies show no benefit. On the accepted international scales of the reliability of research, the latter is considerably more reliable.
“Do your homework….”
I’ve been studying cycle helmets for over twenty years and my MSc dissertation was on the subject: I think I’ve done my homework. About two years ago I wrote an article for a transport magazine on the subject of cycle helmets, and there were four responses: the two people who were convinced that helmets were effective admitted that they had no knowledge of the subject, and the two who agreed that helmets were not effective had read widely on the subject and had conducted their own research. It isn’t the helmet sceptics who need to do their homework, it’s the helmet proponents.
“And don’t make claims, as you say at the end of your post, "when you are completely ignorant of the subject." Your 20 years of experience as a cyclist doesn’t make you a safety expert let alone knowledgeable in the subject.”
And perhaps you could brush up your comprehension skills: nowhere did I say that I have 20 years of experience as a cyclist. It’s actually about 45 years, almost all of which was without a helmet. There was a brief time when I wore one, convinced by the “it might save your life” and “it’s common sense” arguments, but then I hear disturbing rumours that they weren’t effective, so I did some research, and I’ve never worn a helmet again.
I’m also a qualified Health and Safety rep.
I’m also an engineer, and I know that you have to base decisions and policies on the best available data, no matter that it contradicts your own personal beliefs or “common sense”. If we built aircraft using the same sort of data the helmet proponents use, there’d be a plane crash every day.
Try reading “Risk” by John Adams, you might find your deeply entrenched preconceptions being challenged.
I repeat: the original poster would appear to be completely ignorant of the subject, and in fact makes this clear himself “What could be the argument against providing helmets with these bicycles? It seems that the only argument could be the one from logistical difficulty or cost.” And “Am I missing a good argument against helmets?” As a D.Phil. student at Balliol College, University of Oxford, I am astonished that he published such an article without having done the most basic research and discovered the real counter arguments, not just his suppositions. Standards would appear not to be just falling, but plummeting off a cliff.
Jon and Richard, thank you both for bringing such spirited debate to this discussion. First, let me make it clear that this is a Blog post and it should not be confused with a published article. The purpose of this blog is to raise practical issues of ethical interest to stimulate general discussion and debate. As such, the initial posts are not intended to be exhaustive accounts of argument and counterargument, but to highlight a few so that commenters will raise and discuss those omitted. I am glad that we now have a discussion going and I look forward to continuing that discussion.
As we proceed, I would be greatly appreciative if we could focus on the arguments themselves rather than who is making the arguments (i.e. professions or years of experience).
First, let us start by pointing out that a theoretical helmet policy might take one of three major forms:
1. *Helmets prohibited* (government puts up barriers and incentives designed to discourage cycling with a helmet; an example would be a fine)
2. *Helmets optional* (cyclers have the ability to choose to ride with or without a helmet)
3. *Helmets compulsory *(i.e. government puts up large barriers and incentives designed to discourage cycling without a helmet. Ex. The $130+ fine in Melbourne)
In a liberal democracy, the default position should be the moderate position, that of #2 (*Helmets optional*), this is the position that the London Cycle Hire Scheme endorses on their website: “The use of cycle helmets for cyclists within the UK is not a legal requirement. Therefore, it is at the user's discretion whether to wear a helmet” http://www.tfl.gov.uk/roadusers/cycling/15026.aspx, so let us begin by examining this option more closely.
For the helmet-optional position to exist, cyclists need to have the freedom to choose to ride with or without a helmet. To have such a freedom, the riders need to have a negative liberty, or otherwise defined, an absence of coercion in the choice.
Isaiah Berlin, a philosophical proponent of negative liberty, defines coercion: “If I am prevented by others from doing what I could otherwise do, I am to that degree unfree; and if this area is contracted by other men beyond a certain minimum, I can be described as being coerced” (Berlin, 1969: 122) http://plato.stanford.edu/entries/liberalism/#PreFavLib). Moreover, a follower of Berlin would argue that “[…] the liberal state's commitment to protecting liberty is, essentially, the job of ensuring that citizens do not coerce each other without compelling justification. […] Being free is merely a matter of what we can do, what options are open to us, regardless of whether or not we exercise such options (Taylor, 1979).”
Thus applied to our question, governments should deviate from position #2 and infringe on this negative liberty only with “compelling justification,” (it is worth noting that this Berlinian negative liberty is one of the least demanding liberal theories).
The question now is, in the London Cycle Hire, is the choice to ride with or without a helmet freely available (i.e. is it free of coercion)?
The choice to ride these so-called “Boris-bikes” *without* a helmet seems to be freely available by this definition; others do not prevent helmet-less cycling and there is no significant impediment (such as a fine) to helmet-less cycling forced upon cyclers.
The choice to ride Boris-bikes *with* a helmet at first glance seems available too, right? After all no one will prevent cycling with a helmet; neither is anyone threatening to impose a fine for helmet wearing. But upon closer examination, I argue, the choice is not free from coercion and is therefore not freely available.
While the logical step here may not seem clear at first, the basic idea is that not having a helmet available for rent with the bike (in a vending machine or attached to the bike with hair liners available for sanitary reasons) erects such a significant practical barrier to the option of “riding a Boris-bike with a helmet” that this option is not freely available. We can learn from a similar cycle scheme deployed in Melbourne, where cycle helmets are compulsory. very few people rode the bikes at all, averaging around 200 rides/day compared to Dublin's almost 5000 rides/day even though both schemes had a similar number of bikes and stations (The cost of Dublin Bike subscription is a quarter of Melbourne’s but this alone can’t account for the difference). While this case builds evidence for an argument that helmet laws discourage cycle hire riding in general (but far from shows “proof” as it does not correct for differences in the populations, cities, and advertizing) it also shows something else: When Melbourne introduced subsidized helmet vending machines where cyclists could quickly buy a helmet for a fiver (then return it to get $3 back) *cycle share usage increased to 160% of previous levels* in the immediately following months (http://www.melbournebikeshare.com.au/Helmet-locations). While the above caveats also apply to this observation (and the helmet scheme is far from well oiled), it at least gives us good cause to question how freely available the choice of riding such a bike *with* a helmet really is. Since the helmet-less option was unavailable, here, the change in cyclists represents those who would otherwise have ridden the bikes had the option of helmet been practically available ad gives an approximate value to the practical barrier when helmets are unavailable. This suggests that the absence of helmet-options in London and elsewhere might form a significant constraint on the free choice of riding a cycle hire with a helmet.
If the choice of riding a Boris-bike with a helmet is not freely available, then what we have with Boris bikes is not truly a case of #2 (helmets option). There is coercion – not a fine, here, but the practical barrier produced by the absence of a helmet option – that impairs the availability of the option to ride with a helmet. Also note that the government is peculiarly *the source of this coercion and at the same time the guardian against coercion without compelling justification*.
So now the question becomes, is there compelling justification to thus restrict the option of cycle riding with a helmet? **The situation of the Boris Bikes is interesting precisely because this question is the opposite of the one typically argued in the literature of cycle helmets (which is for or against requirement).**
Now, the primary reason offered by the schemes for why helmets would not be available should the rider choose to wear one when these schemes were being introduced, is a financial and logistical one; i.e. these arguments have the form of, it would be expensive to set up vending machines, cumbersome to provide liners, people would steal them, people don’t want to wear them and it would thus be a waste of money etc. This is why I highlighted this possibility in the blog. The argument from economy, however, would have to be of sufficient strength to outweigh the responsibility the government has to ensure negative liberty. When a lot of the cost could be passed onto those seeking to wear helmets (as an extra charge as in Melbourne etc) and by seeking sponsorship by a helmet-manufacturer such as Bell, the argument from economy seems weak even without taking into account possible savings due to helmet-wearing.
Another possible justification for the governmental coercion would be the claim that wearing a helmet is all things considered more dangerous than not wearing a helmet. There is no compelling evidence that helmets are dangerous; anyone arguing that there is not conclusive evidence that helmets prevent head injuries and deaths would need to admit that the case for the reverse (conclusive evidence that they promote these injuries) is orders of magnitude weaker; the studies criticized by pro-choice helmet-ers [many of whom argue more like anti-helmet lobbyists] as flawed (e.g. the case-control studies that you cite, Richard) show risk reduction with helmets (see Jon’s post and discussion below for references). Some show a small non-significant increase in facial injuries or rotational injuries, but a recent report by the UK dept of transportation indicated that it found no support for increased rotational injuries with helmet wearing http://webarchive.nationalarchives.gov.uk/+/http://www.dft.gov.uk/pgr/roadsafety/research/rsrr/theme1/ppr446.pdf. Behavioral data suggesting that vehicles might drive closer to helmeted drivers or that helmeted riders ride correspondingly faster (the risk-compensation theory) is not well supported [see the UK report above, the reviews at the end of this post and http://www.bmj.com/content/332/7543/725.long, though also read the responses to this last paper http://www.bmj.com/content/332/7545/852.2.long, http://www.bmj.com/content/332/7545/852.3.long, and http://www.bmj.com/content/332/7545/852.1.long for a better grasp of the extent of debate]. What is especially confusing (and well noted in Hagel’s 2006 response) is that authors opposed to helmet laws both criticize the case-control studies by suggesting that helmeted cyclers might ride slower and more cautiously (as it might be a safety conscious group) and at the same time suggest that helmeted cyclists might ride faster and thus be at higher risk without suggesting how to resolve this tug of war (for ex, see http://www.bmj.com/cgi/ijlink?linkType=FULL&journalCode=bmj&resid=332/7543/722-a).
Moreover, having a helmet *option*, unlike a compulsory helmet law, would not be expected to reduce the number of cyclists on the street and thus there would be no expected loss in “safety in numbers” (the idea that the more cyclists on the road, the safer the road is for cyclists) or in any health benefits associated with cycling.
**In the absence of compelling justification, the impairment of the cyclist’s ability to choose to ride with a helmet is not warranted. What’s more, we have a curious situation with the Boris Bikes where the very government that is supposed to protect us against unjustified coercion is itself using unjustified coercion. This is why they should provide a helmet option.**
Now back to brain injury. First, is cycling dangerous? Richard, let us assume, as you say, that cycling and walking down city streets have the same head injury stats per km traveled [quote] This does not necessarily mean that they are equally safe and should thus be treated equally. If people on cycles travel more distance on average along the streets than pedestrians, this will make cycling more dangerous than walking. I am not claiming that cycling is horrifyingly dangerous, just that it would be more dangerous than walking. Also, let us remember that these stats were presumably gathered with a portion of the cyclists already wearing helmets; we can say nothing about injuries thus prevented and how that affected the risks.
Second, let us assume that vehicle collisions might be as frequent with pedestrians and cyclists. But falls (self produced or when “nudged” by vehicle or road irregularity) would be more common off of bikes. Many of these falls, are not reported and thus taking into account neither in most case control studies nor the longitudinal ones; the costs of these unreported accidents are staggering and have previously been underappreciated in cost-benefit discussions [http://www.ncbi.nlm.nih.gov/pubmed/20728675] Also, many of these falls result in avoidable concussions. Concussions, or mild brain injuries, are increasingly being understood to be more serious than previously thought. Concussions can impair cognitive function in youths for month and deprive them of proper educational opportunities. Also, concussions significantly increase the risk of seizure for up to 10 years post accident http://www.sciencedirect.com/science/article/pii/S0140673609602142.
Richard, what you seem to be most concerned with is a discouragement of cycling in general and thus the health benefits thus associated. I cannot see how providing *an option* for a helmet at Boris Bikes would discourage cycling and must assume that you mistakenly had a compulsory-helmet argument in mind.
Nonetheless, it important to step back from the common intuition that cycling produces better health (and all the propaganda thus involved) and look at the evidence. Emerging research suggests that not all cycling is created equal and that some types of cycling may produce health risks that offset the benefits. Namely, cycling in dense Urban areas (like London) leads to the inhalation of much vehicle exhaust, which is suggested by recent research to have significant health costs that might outweigh benefitshttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC3060010/. Second, low intensity, short bursts of physical activity provide little health benefit. Since Boris Bikes are both exclusively urban and designed for people making short, spur of the moment trips (not everyday commuters), it is likely that these bikes have less positive impact on health than we might initially intuit.
Also, the position that helmet laws decrease cycling participation is itself controversial, please seehttp://onlinelibrary.wiley.com/doi/10.1002/ebch.193/full. So this effect should not necessarily be assumed.
Finally, to the evidence about effects of helmets on safety (for anyone else out there, I find this review to be helpful and reasonably balance, though it is clearly positional and does not include the past 4 years of new research pointed to at the end of this response http://www.sciencedirect.com/science?_ob=MiamiImageURL&_imagekey=B6V5S-4KPFKRD-1-1&_cdi=5794&_user=1861184&_pii=S0001457506001126&_check=y&_origin=&_coverDate=01%2F31%2F2007&view=c&wchp=dGLzVlz-zSkzV&md5=2277d96c00f0982bb47bd9325b5ea979&ie=/sdarticle.pdf.
While you, Richard, (and it seems much of cyclehelmets.org) categorically dismiss case-control studies as “flawed” and “biased,” the longitudinal studies you mention have their caveats as well. Across so much time and between such different populations (without reference populations) there are many confounding variables that should not be ignored. for example, one study (http://www.cbdbug.org.au/wp-content/uploads/2011/06/helmet-research-paper-released/Attachment-2-Voukelatos-and-Rissel-Released.pdf) initially indicated that legislation in New South Wales did not lead to a decrease of head injuries relative to limb injuries; this article did not stand the test of peer review and the journal retracted it post-publication because of very basic methodological errors that the authors neither corrected nor explained (pg 41 http://www.acrs.org.au/srcfiles/ACRS-Journal-22No1WebLR2.pdf). Reanalysis of the data in June 2011 by another group (the one who pointed out the methodological errors in the Voukelatos paper) controlled better for confounding variables (including the oft cited concomitant decrease in pedestrian head injuries) and reported “Head injury rates decreased significantly more than limb injury rates at the time of legislation among cyclists but not among pedestrians” http://www.sciencedirect.com/science/article/pii/S0001457511001485. So it is not as if the longitudinal studies point uncontroversial towards helmet legislation being ineffective; this too seems to depend on how one handles with confounding variables and whether one does so well or poorly.
As Jon rightly points out, Case control studies are useful. Different methodologies give different types of information, which is why it is important to approach questions from complementary angles. Most methodologies have limitations and caveats, but this does not mean that we have to throw the whole thing away; we learn what we can from each methodology and try to get a better understanding of the issue at hand (for an interesting an thorough account of several logical fallacies committed in the discussion of cycle helmets and safety, please see http://www.sciencedirect.com/science/article/pii/S0001457505002101).
While you may remain unconvinced, Richard, I must agree with Jon on the quality and sum of the data in support of helmets role in safety. Of course a randomized Control-trial would be best. And of course it should be pointed out that helmets will not do much for casualties due to freight trucks running over cyclists http://www.biomedcentral.com/1471-2458/10/699/. As it is, there are decent arguments on both sides, but considering the literature as a whole, I see it swung in the direction of helmets for heads for the following reasons:
1. The question of whether mandatory helmet legislation is effective in reducing head injuries and deaths is importantly different from the question of whether properly worn helmets prevent head injuries and deaths
a. Theoretically, the former could be answered logically in the negative and the latter in the positive. J. Adams, for example, a leading proponent of risk compensation theory points out this difference in his introduction when referring to a previous Cochrane review of helmet safety, “We accept the principal finding of their review—that protective helmets protect in the event of an accident—but not the policy conclusions that they derive from it” http://injuryprevention.bmj.com/content/7/2/89.extract.
b. As indicated above on the section about New South Wales, the effects of implementing legislation now have some better designed studies supporting their efficacy in certain populations (ex the 2011 New South Wales study).
2. Not all helmets are created equal
a. Improperly worn helmets do not confer as much benefit as properly worn helmets
i. A large number of youths and adults wear helmets improperly. 95% of children and adolescents in this study, for example, even though the community supported helmet use http://pediatrics.aappublications.org/content/112/2/320.short (though proper-use statistics vary considerably between studies and populations, see http://injuryprevention.bmj.com/content/15/2/125.abstract).
3. New Evidence points back in the direction of helmets.
a. a reinterpretation of the Glenn and Fadden 2001 Cochrane review, for example, controlling for variables such as publication bias, yields a smaller but still large risk reduction for helmets http://www.sciencedirect.com/science/article/pii/S000145751100008X
b. Moreover, yet another recent Cochrane review (Macpherson 2008) http://onlinelibrary.wiley.com/doi/10.1002/ebch.211/full further supports the efficacy of helmets and its conclusions were recently corroborated by the publication of a 12,000 cyclist case-control study http://injuryprevention.bmj.com/content/16/Suppl_1/A205.1.abstract
c. Responses to Macpherson 2008 also raise evidence to question the premise that bicycle interestingly question the premise that declines in cycle riding are inextricably tied with helmet legislation http://onlinelibrary.wiley.com/doi/10.1002/ebch.193/full
With all the above discussion in mind, if helmets may be beneficial for health (and this is where much of the evidence points) or at least not harmful a governmental stance of impeding the option of cycle helmet wearing with Boris bike riding is unjustified. As it is, we can go further to say that the government at a bare minimum should protect the negative liberty to choose to wear a helmet (by making them realistically available should cyclists choose to wear them in these schemes. The most extreme argument, that for requirement is an importantly different one, but one not without a significant amount of support considering the most up to date research.
A final point is that the London Cycle scheme is one of liability. Interestingly, the scheme currently makes it clear that it provides no coverage for personal accidents and recommends that users take out such a policy themselves http://www.tfl.gov.uk/roadusers/cycling/15026.aspx. Furthermore, the scheme hasn’t been accident free. 100 accidents were reported (and there were likely unreported accidents http://www.guardian.co.uk/uk/bike-blog/2011/jul/10/boris-bikes-hire-scheme-london. If there are people who ride who would otherwise wear helmets if they were reasonably available and get head injuries, could they claim that the scheme should be held liable?
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