Saturday, March 24, 2012

Cycle helmets– why should they be necessary

In the last month my daughter, sister and son’s girlfriend have all fallen down stairs. I was going to say taken a tumble – but perhaps that lessens impact and implies I might find it slightly amusing, which I don’t. It got me wondering why is there so much fuss  about cyclists wearing helmets, who is making the fuss and why?  What is it that makes us decide that, for the good of society additional safety measures need to be taken for a particular activity?

I would like to think that it is perhaps the data that informs our decisions and in some cases that is probably the case, but it is probably not so in all cases. Sometimes the issue is perhaps a case of those that speak loudly enough get heard. For instance. Is there a safety threshold, or should that be a danger threshold, that such safety measures get measured against.

Having been involved in research the Scientist in me would like to think that of course it is data driven. But when I did the unthinkable and moved into a sales role I came to appreciate that decisions are often made for more intangible reasons and then the decision uses data to backfill the argument. (For the record, my first job title was “Junior Scientist” and sales was actually hard word and great fun and not the great sell out I might have though 10 years earlier.)

An interesting unit of risk is the micromort – which represents a one in a million probability of death.  Now that is such a small probability that all sorts of of regular activities clock up micromorts pretty rapidly. From the link it is suggested that for people living in the UK the risk of premature death is approximately 1 micromort per day. Now that is an average across a large population and the distribution might be affected by many factors.

The same article then goes on to give examples of activities that increase death:

  • Travelling 6 miles by motorbike (accident)
  • Travelling 17 miles by walking (accident)
  • Travelling 10 miles (or 20 miles) by bicycle (accident)
  • Travelling 230 miles (370 km) by car (accident) (or 250 miles)

Several factors stand out, the first is that several numbers are quoted for two of the activities – so even agreeing the numbers is not that straightforward and travelling by car is over ten times less risky than by bicycle! No the astute reader will realise that these are the risk associated with accidents. There are also risks from leading a sedentary life and benefits from the exercise associated with cycling. Indeed quite a bit of research indicates those health benefits are substantially greater than the risks. (Do the Health Benefits of Cycling Outweigh the Risks? – one of the oft-cited papers). What I should point out is that this paper studies cycling in the Netherlands where cycling is safer (and cycle-helmet wearing is much much less.)

Helmets protecting against low hanging branches
Roman Road Cambridge to Balsham

So although the “number” suggest that cycling is safe (indeed better for you than driving)   why do so many feel that it is dangerous.  Well let’s get back to the “falling down stairs” problem. My daughter and the person she was with both ended up having to visit casualty. Fortunately for my daughter she was just bruised, she was carrying a box of books with another student who was not quite so lucky and fractured her arm. (Mind you when she was younger my daughter did have a fall down stairs that broke her arm.  In my sister’s case she was badly bruised and it was her second notable fall down stairs.

So how dangerous is it to use the stairs? Well a quick search throws up this BBC headline from 2000, “1,000 die from stair falls”. More up to date is this article in the Guardian – “Mortality statistics”. You can access the more complete data but it does have a summary of the Major causes of death 2010.

A few extracts:

Pedestrians killed by a transport accident 398
Of which 2 were killed by accidents with cyclists
Of which 188 killed in accidents with car, van, lorry & bus

Cyclists killed in transport accidents 96

Motorcyclists killed in transport accidents 347

Car occupant killed in transport accidents 808
(note this does not include all motor vehicles)

Fall on or from steps and stairs 655

As with all data it has its foibles – but those stairs do look pretty dangerous don’t they.

Wot – no high-vis – this Cyclist plays it safe at Cambridge Railway Station
earing a helmet to ascend the stairs

So why is there not more of an outcry. Well I think there are three reasons. I would make an educated guess that the number of “stair journeys” exceeds the number of cycle journeys. So we would see going up or down the stairs as less risky per journey  and so not worth bothering about – although in reality it kills more people per year. The second reason is that I would imagine that majority of deaths tends to come with old. The third reason is we probably consider that using the stairs is pretty much within our control.and hidden away and something many of us participate in. So we might be reluctant to be told how to use stairs.

I suppose there is also the risk versus benefit angle to consider.sorting out all the stairs would probably be quite expensive.

So why do lots of car drivers want cyclists to wear cycling helmets.- apparently 97% of AA members think cyclists should wear a cycling helmet..Is it because cycling is dangerous, or because it would save lives, or is it about making car drivers feel less guilty about the way in which they use the roads without paying sufficient attention to road users requiring extra car (rules 204- 225).

Cyclists wearing helmets and high-vis jackets heading into Lode

I think that the car drivers are unwittingly falling into the trap of the best defence is to attack. It becomes a blame factor, along with I didn’t see him and the sun was n my eyes.

I still think that car drivers should focus more on the reality that one more cyclist, means one less driver which means less congestion. We also need to focus on what it takes to make every day cycling safer in terms of the infrastructure and motorist behaviour.


  1. I guess a helmet will help somewhat but agree there are many other factors as to why helmets are being pushed.

  2. A useful analysis of the risks of cycling compared to other activities for which there is never any call for compulsory safety equipment, although there is one more point that could have been made: nowhere with a helmet law or huge rise in helmet wearing because of propaganda campaigns can show any reduction in risk to cyclists.

    Despite more than twenty years of hard data, and predictions of 85-90% reductions in cyclist deaths, there has been no reduction other than that caused by the fall in cyclist numbers after the introduction of the law.

    To extend your use of comparative risks, you are much more likely to suffer ill health and death through not exercising than you are from cycling, and in fact, regular cyclists live longer and suffer less from all forms of illness. It would appear that not cycling is much more dangerous than cycling.

    Do we really need all kinds of health and safety warnings for something that is likely to make you live longer and be healthier?

  3. Thank you for your comments. It does seem that there has been an undue fixation on the issue of wearing cycling helmets whereas what we should be doing is encouraging more people to cycle. However the mere fact that some quarters "insist" on the wearing of cycle helmets implies that cycling is a dangerous activity, which then discourages some cyclists.