Let’s get to the core of Bradley Wiggins’ (since partly retracted) comments which have caused such frenzied debate. We are actually going to have a brief look at the accumulated evidence on the
effects of cycle helmet wear – something which is rarely done. What this indicates is a remarkable lack of evidence of benefits. (This is apart from the diversionary – “red herring” – and the “dangerising “effects of helmet advocacy which are themselves worryingly negative.)

Although my view is that cyclists should indeed be allowed to wear helmets, this is on the basis of allowing all kinds of behaviours which have minimal, zero, or indeed negative benefits for the
user. It would be quite possible for “road safety” professionals with a commitment to prohibiting certain behaviours to do so. The point is to show the absence of positive evidence and to open the Pandora’s Box of road user response to danger, as we do below…

A fairly typical response by professionals in this debate is made by our colleagues in the Transport and Health Study group in The Times of, 4 Aug 2012
“Sir, It is safer to cycle in England than to drive in France (“Sorry, Bradley, helmets are not the answer”, Christian Wolmar, Opinion, Aug 3). For young male road users, it is safer to cycle than to drive. For older road users, the added risk of cycling rather than driving is about comparable to the added risk of driving on an all-purpose road rather on a motorway. This small
added risk is, for the individual, outweighed many times over by the health benefit. Cycling increases life expectancy whereas driving reduces it. For the population as a whole the small added risk is considerably outweighed by reduced risk to third parties.

This response is important but does not, however, actually question whether helmet wearing will result in a lower chance of sustaining injury – including head injury – when cycling. There have been some good responses to Wiggins as well as our own in the previous two posts , here , here .and  here .

However, many responses (as in The Times editorial ) and others reported here , are based on simply saying that they would like other things to be considered instead, like (unspecified) “infrastructure”. Or the usual anodyne requests for all road users to show courtesy to each other while selling so-called “safety aids” like cycle helmets.

The medical scientist Joe Dunckley collects his posts on the evidence here , stating “ Last year I went into some detail about why existing research into the efficacy and safety of helmets for cycling does not come close to the standard of evidence that is normally required and which we would usually demand for a medical intervention (my emphasis RD) (which is what they are). Basically an application to helmets of all those things that Ben Goldacre (another medical scientist committed to myth busting RD) bangs on about.

There is also a substantial amount of peer reviewed analysis of available scientific and supposedly scientific work on the web site of the Bicycle Helmet Research Foundation .

In 2008, 2009 and 2010 the Department for Transport ran a major study on cyclist safety. It has appeared to many that the study did not deal adequately with methods of reducing danger to cyclists, indeed on a real programme of cyclists’ safety. A large proportion – in fact the major part of the programme – was devoted to cycle helmets.  The CTC and others have described how this work on helmets failed to show possible benefits from real world studies of helmet wearing, relying on a spurious interpretation of laboratory work on supposed simulations of cyclist
collisions. This “study”, and the 10-16% finding in particular, is one of the dodgiest pieces of work in the helmet literature , yet was referred to in the recent Times “analysis” as a “pro” piece of evidence for helmet wearing worth considering.

(Indeed, one can argue that this a classic example of the red herring effect: a study supposedly devoted to cyclist safety has a  major part of its conclusions directed towards consideration of helmet wearing rather than a danger reduction approach, or even one including reference to cyclists’ responsibilities in terms of road positioning. We hope to give a longer comment on this in the future).

Here is one coment on this work: Writing as a member of the advisory group for the Department for Transport’s cycling safety study, John Franklin clarifies a report of its findings by the transport practitioners journal Local Transport Today (LTT 22^nd January) in February 2010:

A classic response given by helmet advocates is the “a helmet saved my life” statement. Franklin gives an interesting response in another letter to LTT in March 2010 which  I quote from:

Mr R (LTT 5 Mar) has every right to wear a cycle helmet if he wishes to, …However, his justification for wearing one – that a friend’s helmet was split in two in a crash – is weak. Helmets work through the crushing of the inner liner, which can reduce to a limited degree the acceleration of the head in an impact. By comparison, a helmet splitting absorbs much less energy. If a helmet splits before the liner has fully crushed, then it has failed and most likely has given very little protection. In practice, it is common for helmets to split before there has been any crushing of the liner. Indeed, the only helmets I have seen with a well-crushed liner have been ones where the wearer has been in such a severe impact that a serious head injury has been suffered regardless. On the other hand, a considerable number of helmet wearers report having been ‘saved’ by a splitting helmet – a number grossly disproportionate to the number of actual head injuries suffered by bareheaded riders. Unfortunately, those who uncritically advocate helmet use appear unconcerned about investigating the additional collisions that seem to result.

What this area of discussion points to is the big open secret of road safety: people adapt to their perceptions of risk.

With cycle helmets, the point here is not that people on bicycles are seriously hurt or killed in collisions where even what helmets are supposed to do by their advocates is irrelevant . Nor that helmets may be ineffective even against impacts. It is that wearers adapt to their use in such a way that the benefit is absorbed at least partially, if not totally or more than totally by changes
in their behaviour arising from wearing a helmet in the first place. After all, only a very slight change in levels of alertness and vigilance is required to partially, totally, or even more than totally absorb the alleged benefits.

I have quoted one study before which: found …parents allowed their children to engage in greater risk-taking in activities such as bicycling when wearing safety gear than when not, and the parents’ explanations showed that they assumed the gear would fully protect their child – including even parts of the body not covered (e.g. a bike helmet would protect limbs) – and prevent injury regardless of the child’s level of risk taking. This optimistic, almost magical, reasoning seems to be shared by children and their parents during periods that may be formative in the development of safety orientation. (My emphasis)”.

Does this matter? Maybe not, but there are other adaptive effects that should be considered. Any possible change in behaviour by other road users is important . More important is what I have called “long term risk compensation” referring to rhe nore widespread effects of an intervention: in this case we have the “red herring” or diversionary effect of considering helmets in the first place.

While  risk compensation (RC) or behavioural adaptation is an obvious fact of life,  “road safety” professionals are unwilling to accept it. Doing so undermines the  case for much of what their lives is about.

Considering RC involves referring to the work of John Adams on interpreting Reuben Smeed’s analyses of road deaths over time (the Smeed curve) and numerous examples of interventions resulting in adaptive behaviour by those affected. The implications include accepting that many reductions in casualties have happened spontaneously, and not as the result of professional “road safety” (RS) interventions. More importantly, it involves accepting that much of the legacy of protecting the motorised from the consequences of their rule and/or law breaking has been to shift risk on to the more vulnerable – and more benign – forms of transport user.