Bicycle Helmet Safety Institute

The Bicycle Helmet Safety Institute (BHSI), founder and sole known member one Randy Swart, sets out its stall at http://www.bhsi.org. It is a typical helmet compulsion campaigning organisation.

One of the things which persuades me that helmet compulsionists are fundamentally wrong is the fact that they never seem to be entirely honest. Here's an example: there is a range of pro-helmet research estimating the efficacy of helmets, which averages out at around 2/3 of injuries saved (this is a contentious conclusion, but let that pass for a moment). BHSI say "88% of cyclists' brain injuries can be prevented by a helmet" - this figure occurs in only one of the studies, and the authors revised the estimate down to around 2/3 following criticism of their methodology and sample selection. The correction was published in 1996, is widely known, and certainly no serious campaigner can fail to be aware of it, so using the higher figure - which was in any case a lone example at the very top of the range of estimates - is simply dishonest. It's as if a claim of 2/3 of injuries saved is not enough, so the biggest number possible must be used. It suggests to me a lack of confidence in the underlying merit of their argument.

Statistics
What was it Winston Churchill said about statistics? Here is a quick peek at their Statistics page:


 * There are 85 million bicycle riders in the US
 * About 800 bicyclists die in the US every year
 * About 540,000 bicyclists visit emergency rooms with injuries every year. Of those, about 67,000 have head injuries.
 * Bicycle crashes and injuries are under reported, since the majority are not serious enough for emergency room visits.
 * 1 in 8 of the cyclists with reported injuries has a brain injury.
 * Two-thirds of the deaths here are from traumatic brain injury.
 * 88% of cyclists' brain injuries can be prevented by a helmet.
 * Many years of potential life are lost because about half of the deaths are children under 15 years old.
 * Direct costs of cyclists' injuries due to not using helmets are estimated at $81 million each year.
 * Indirect costs of cyclists' injuries due to not using helmets are estimated at $2.3 billion each year.

So, 540,000 bicyclists visit emergency rooms of which 67,000 have head injuries. That's one in eight. They then say that one in eight cyclists with reported injuries has a brain injury. So 100% of all those head injuries (which other sources indicate includes all injuries to the head and face) results in a brain injury. It doesn't add up, does it?

Note also the uncorrected 88% figure from the original Thompson, Rivara and Thompson study, since revised by its authors. I asked about that and received the following reply:

Does that sound like a strong reason for continuing to use a figure which is wrong, given that the corrected figure is in much better agreement with other studies? If you believe that the scale of claims made for effectiveness has any effect on cyclist behaviour (or indeed on the behaviour of insurance companies), then clearly this is far more important than BHSI think. And even if you don't, why make yourself a hostage to fortune by using a known incorrect figure, giving your opponents a ready means to discredit your arguments?

Apparently two thirds of deaths are from traumatic brain injury. Leaving aside whether an inch of polystyrene can make the difference between a fatal brain injury and a non-fatal brain injury, which is unproven, there are two things we know for certain about fatal cyclist head injuries: first, a substantial proportion of those cyclists also have other mortal injuries (16/19 in one recently published study); and second, that the major causes of mortality due to head injury are diffuse axonal injury (DAI) and subdural haematoma (SDH). Of these the worse by far is DAI, which is also implicated in most cases of permanent intellectual disablement. There is no suggestion in any literature that cycle helmets mitigate DAI in any way - it is essentially due to rapid accelerations of the brain matter within the skull. It is usually caused by rapid twisting, which a helmet can do nothing to alleviate. There are even some suggestions that helmets might make this kind of injury more likely.

Now whatever the merits of the argument overall, the use of a wrong and greatly inflated claim, the implied assertion that every head injury presented to an emergency room amounts to a brain injury, and conflating all brain injuries with potentially life-threatening neurological trauma when the most significant neurological pathology is from a type of injury which helmets do nothing to mitigate - these things undermine the credibility of the argument sufficiently that every claim on the page must surely be discounted unless corroborating evidence can be found.

One closing point on this page: BHSI state that "Helmets are cheap. The typical discount store price has risen from under $10 to about $15, but there are still models available for under $10 at major retailers." What are the chances of finding a good quality, comfortable, well-fitting helmet at those prices? Not all plastic hats are created equal. Mind you, at least one Chinese helmet maker sells many Snell certified lids, whihc is more than can be said for the vastly more expensive offerings from Bell Sports.

There are no anti-law activists! Never!
I first started studying BHSI's website when this link popped up in Google. It amused me for a number of reasons. It's a fairly open page (for a helmet compulsionist organisation), but it includes this Comical Ali-style statement:

Gentle reader, you may have realised that I am (or at least have been) a newsgroup regular. I can tell you that the overwhelming view of uk.rec.cycling, for example, is against compulsion. Even those who are strongly pro-helmet are almost all anti-compulsion. Nor have I seen any evidence of the net.police banning helmet threads in groups other than rec.bicycles.soc. Naturally every now and then someone comes up with a "helmets are a no-brainer" type of comment, and when that happens they tend to get educated fairly promptly by whoever is first on the scene. So it seems to me, anyway. Whatever your view on helmets, you have to recognise that the issue is anything but cut-and-dried, and you will probably also understand that in the United States in particular no amount of "think of the children" is sufficient to persuade a lot of people that the Government should be taking an interest in their choice of hat.

A second section of that page also invites consideration:

I like the idea that use of gloves indicates cyclists are more worried about road rash than head injuries. Where does that come from? Padded gloves are worn for comfort on drop-bar bikes, and incidentally to prevent cuts if you come off. To suggest that anybody is worried about cut hands and doesn't care about doing a face-plant is profoundly odd! Of course you can't prove risk compensation, but the two examples they hold up as having been used "at one time" - seat belts and ABS - are both very much current, and in both cases there is a strong case to be made to support risk compensation theory. Research from two different countries comparing the driving style and crash record of taxi drivers in a single fleet with a mixture of ABS and non-ABS cars showed that the drivers drove faster, followed closer, and had no fewer crashes in ABS equipped cars. Nobody believes in risk compensation - that's why it happens.

Ask any club cyclist
A claim which appears more than once on the BHSI site goes along the lines of "Ask any club cyclist, whose shared experience with other cyclists has shown them the pattern clearly." The USA may be different. If you ask one club cyclist from St Albans he will tell you that following a header over the bars (a very rare thing for a cyclist, by the way) he suffered concussion and cuts. He was not wearing a helmet. In this crash, of the kind which in the average "helmet saved my life" anecdote survival would be credited solely to the plastic hat, the cyclist's 70-year-old standard-issue skull (to a non-kitemarked design originally perfected back in the mists of time) provided sufficient protection. A plastic hat may have reduced the severity of the concussion (though probably not) and would have saved some of the cuts. And that's it. I don't like road rash on the head, which is why I usually wear a hat, but expecting it to save more than the most superficial injuries is to court disaster.

About half the riders in my club wear plastic hats, and about half don't. More offroad riders wear hats than do roadies and tourists. Older riders (i.e. those experienced cyclists to whose age and judgement BHSI suggest we defer) are markedly less likely to wear them than younger riders, not least because they have learned the fundamental lesson of bicycle safety: the best way to prevent injury is to ride well.