How to ask a helmet question?

This sub-forum all discussions about this "lively" subject. All topics that are substantially about helmets will be moved here, if not placed here correctly in the first place.
alicej
Posts: 1301
Joined: 14 Oct 2010, 10:16pm
Location: Leeds, West Yorkshire

How to ask a helmet question?

Postby alicej » 9 May 2011, 11:01pm

Is it OK to start a thread and then abandon it if it gets too mad for me? :?

My problem is this;

I usually wear a helmet, but not always.

I'm not entirely sure of my own reasons for this, and would like to make more informed decisions about it.

People on here would be likely to know things like interesting stats and studies, maybe suggesting things like which journeys or which kinds of roads it would be most useful for me to wear a helmet on, and when it might be counterproductive.

But people here also have such strong views on the subject that threads on helmets seem to quickly veer into sarcasm, implying that people with opposing views are stupid, etc, rather than the kind of reasonably objective studies and research that I'd prefer to base my choice on. That's making me afraid to ask.

Also there seem to be many references to studies which are so badly designed that they leave loads of relevant variables uncontrolled for, making them completely useless except for in sustaining pretty much endless circular conversations. Is the answer to the The Great Helmet Question really that we just don't know if helmets help or hinder except in very specific circumstances (which we don't know if we'll encounter on any given journey)?

Which are the best designed studies on this subject? Which are the ones that could help me think about my own personal risk, or does evidence only really exist on a population-wide basis? Is it possible to have a sensible, helpful conversation about helmets?

P.S. Although I fully appreciate why the helmets subforum has been subforumed under "Campaigning and Public Policy", I'm really thinking about how to make my own personal choice here, rather than about the issues more relevant to public policy on helmets.

thelawnet
Posts: 2311
Joined: 27 Aug 2010, 12:56am

Re: How to ask a helmet question?

Postby thelawnet » 9 May 2011, 11:06pm

alicej wrote:Which are the best designed studies on this subject?


The ones that support your point of view. :wink:

There are lots of studies on both sides and you can pull out ones for whichever side you want and then someone pulls out the opposing side and it all ends up frightfully tedious.

snibgo
Posts: 4604
Joined: 29 Jun 2010, 4:45am

Re: How to ask a helmet question?

Postby snibgo » 9 May 2011, 11:31pm

alicej wrote:Is it OK to start a thread and then abandon it if it gets too mad for me? :?

Sure. But you are poking a hornets' nest, as you know.

alicej wrote:I usually wear a helmet, but not always.

Likewise.

alicej wrote:I'm not entirely sure of my own reasons for this, and would like to make more informed decisions about it.

I think I've worked out my own reasons, which are partly subjective. My poor sense of balance (caused by a head injury) gives me a slight tendancy to fall off my bike when stationary, and that's the type of accident helmets are best at.

A good place to start reading is the Snell B95 standard, at http://smf.org/stds.html . This will tell you what helmets certified to that standard are supposed to do, and how they are supposed to work.

A proper study would put a few thousand cyclists through a series of controlled collisions, with or without helmets, and see what happens. But that wouldn't be ethical, and wouldn't tell us whether helmets affect accident probability.

Mike Sales
Posts: 4505
Joined: 7 Mar 2009, 3:31pm

Re: How to ask a helmet question?

Postby Mike Sales » 9 May 2011, 11:36pm

How could any study tell you more about your own safety/risk taking than you already know yourself? You have been making your own decisions about how to cope with the risks of the road for (fill this number in yourself) years. Do you doubt that your own behaviour has much more bearing on your risk level than a bit of polystyrene can possibly have? All studies are a sketchy attempt to draw conclusions from the past aggregate risk taking and its results for a sample of cyclists of varying size. What you are looking for is information about the future. It is not available. We all make decisions about cycle riding and indeed life in general on the basis of inadequate information. "Safety" is not attainable.
All that is available are generalisations. If we stick to looking at Government figures, (not expecting any interpretation, or reading someone else's conclusions)we see that the difference in cyclist death rates in different countries dwarfs even the 85% protection rate wrongly claimed by the most gung ho helmeteers. I want British cycling to be as safe as German, Dutch or Danish (about half our death rate, very roughly speaking), not as dangerous as Australian, American or Kiwi (something like twice our death rate). The attitude to helmet wearing in these countries is well known. Without going as far as saying that helmets make cycling more dangerous, they don't seem to make it safer.

User avatar
meic
Posts: 19355
Joined: 1 Feb 2007, 9:37pm
Location: Caerfyrddin (Carmarthen)

Re: How to ask a helmet question?

Postby meic » 9 May 2011, 11:42pm

It would appear that we just dont know how effective helmets really are.

Which is odd because if they were effective it would have shown up by now.

You could try looking at the manufacturers' own claims about the effectiveness of their products. You will see that they are careful to say nothing more than they meet the relevant manufacturing standard.

I try imagining exactly the sort of crash circumstances when I would really like to have a helmet on, every time I do so I think I had better wear a motorcycle helmet in that case.

Then I think about the sort of crash scenarios that I think are likely and that worry me and it is pretty clear that a helmet would not be of much use at all.

Thinking of your question on another thread: when I am cycling along on dodgy downhills with blind corners and plenty of gravel, I do have concerns for my safety and I dont fancy getting gravel rash and I wouldnt go any faster just because I had a helmet on.
Equally I dont think that my lack of a helmet makes me go any slower when I feel the road is safe, I have never had a helmet on when going for the elusive 50mph.

Why not get the helmet out, put it on the table, look at it and think "How much protection do I think that will give me?"
If you think that it will actually be of use then you might be happy to wear it..
Yma o Hyd

thirdcrank
Posts: 28687
Joined: 9 Jan 2007, 2:44pm

Re: How to ask a helmet question?

Postby thirdcrank » 9 May 2011, 11:44pm

How to ask a helmet question?


Best to don some protection first. You might try some sort of protective headgear for starters. :roll:

irc
Posts: 4673
Joined: 3 Dec 2008, 2:22pm
Location: glasgow

Re: How to ask a helmet question?

Postby irc » 10 May 2011, 1:04am

The fairly recent TRL review of helmets, how they work, helmets studies, and protection given is worth a read.

http://www.trl.co.uk/online_store/repor ... idence.htm

My take on the subject is that helmets do give some protection. Possibly more from minor injuries than serious or fatal. One stat in the report is that helmets would have prevented 10-16% of a sample of closely studied fatal accidents. In other words they will make cycling safer but are not a pancea. Things like route choice and rider skill are far more important.

As I think my personal risk is low with zero previous injury cycling accidents and no high risk activities like road racing or technical MTBing I think my personal risk is so low a helmet is not needed. Wearing a helmet is a perfectly reasonable choice for someone whose risk profile or as importantly attitude to risk is different. As long as you realise that helmets the protection is limited and don't allow the fact you are wearing a helmet to alter the risks you take.
No one believes more firmly than Comrade Napoleon that all animals are equal. He would be only too happy to let you make your decisions for yourselves. But sometimes you might make the wrong decisions, comrades, and then where should we be?

thelawnet
Posts: 2311
Joined: 27 Aug 2010, 12:56am

Re: How to ask a helmet question?

Postby thelawnet » 10 May 2011, 1:31am

irc wrote:The fairly recent TRL review of helmets, how they work, helmets studies, and protection given is worth a read.

http://www.trl.co.uk/online_store/repor ... idence.htm


I started reading this and thought 'ooh 122 pages', but unfortunately I got to about page 40 and that was it, the rest was bibliography and appendices.

It devotes considerable space to discussing how helmets are designed to work (in terms of deceleration from a height) plus more space on effectiveness in real world accidents. Sadly they refuse to address the question of whether or not cycle helmets make cyclists, overall, safer; they are only able to say that 'in 10% of fatalities it is believed a helmet would have saved the life' (or similar wording). Which is all very interesting, but not I think going to answer the question 'is it worthwhile wearing a helmet', which requires far more consideration. A sort of logical process for helmet wearing:

Q1. Am I more likely to have an accident if I wear a helmet?
Q2 If yes, is the increased risk offset of having an accident offset by the protective benefits of wearing one?
Q3 If no, do cycle helmets provide a net reduction in injuries in the event that you do wear one? (The answer to this is almost certainly yes, and is essentially the only question addressed by the trl pdf above.)
Q4 Assuming that helmets do not increase the risk of accident, or that if they do it is offset by injury reduction powers, is the risk associated with cycling sufficient to justify wearing a helmet? (Cf. images such as this one:
Image) Compare with other day-to-day activities and risk we take, such as crossing the road. Is cycling dangerous, compared to say climbing Everest, or base jumping (answer: no)?

TonyR
Posts: 5390
Joined: 31 Aug 2008, 12:51pm

Re: How to ask a helmet question?

Postby TonyR » 10 May 2011, 7:59am

irc wrote:The fairly recent TRL review of helmets, how they work, helmets studies, and protection given is worth a read.

http://www.trl.co.uk/online_store/repor ... idence.htm

My take on the subject is that helmets do give some protection. Possibly more from minor injuries than serious or fatal. One stat in the report is that helmets would have prevented 10-16% of a sample of closely studied fatal accidents. In other words they will make cycling safer but are not a pancea. Things like route choice and rider skill are far more important.


That TRL report and 10-16% statistic has a serious problem. The report basically says after reviewing the evidence that the effectiveness of helmets is unknown. They then say but lets assume anyway they are 50% effective and if they were, they would prevent 10-16% of accidents. They then headline that figure. So a conclusion which is not based on any evidence whatsoever.
Last edited by TonyR on 10 May 2011, 12:18pm, edited 1 time in total.

TonyR
Posts: 5390
Joined: 31 Aug 2008, 12:51pm

Re: How to ask a helmet question?

Postby TonyR » 10 May 2011, 8:27am

alicej wrote:People on here would be likely to know things like interesting stats and studies, maybe suggesting things like which journeys or which kinds of roads it would be most useful for me to wear a helmet on, and when it might be counterproductive.

...............

Which are the best designed studies on this subject? Which are the ones that could help me think about my own personal risk, or does evidence only really exist on a population-wide basis? Is it possible to have a sensible, helpful conversation about helmets?


The good news is that the risk from cycling is so low that whatever you choose won't really matter in practice. So go with what you feel most comfortable with but heed the advice of an expert on ski helmets who said if you do choose to wear one, act as if you weren't wearing one.

Because of the rarity of events, its very unlikely that we will ever have the evidence at other than the population level. For the UK context though the best designed studies on the subject are the two by Paul Hewson looking at the UK population data and which are very open about their limitations.
http://dx.doi.org/10.1080/15389580590931590
http://dx.doi.org/10.1016/j.aap.2005.03.020

Also in your consideration think about what you are worried about. A cycle helmet is designed to protect against simple falls at speeds up to 12.5mph. It is not designed to protect against being hit by a motor vehicle. The impact effect goes as the square of the speed so being hit at even just 20mph will exceed the helmet design specification by two and a half times. For those types of accidents your best bet, whether you wear a helmet or not, is to get cycle training to avoid the accident in the first place. So either go on a training course or read Cyclecraft.

Good luck.
Last edited by TonyR on 10 May 2011, 12:18pm, edited 1 time in total.

irc
Posts: 4673
Joined: 3 Dec 2008, 2:22pm
Location: glasgow

Re: How to ask a helmet question?

Postby irc » 10 May 2011, 9:04am

TonyR wrote:
irc wrote:The fairly recent TRL review of helmets, how they work, helmets studies, and protection given is worth a read.

http://www.trl.co.uk/online_store/repor ... idence.htm

My take on the subject is that helmets do give some protection. Possibly more from minor injuries than serious or fatal. One stat in the report is that helmets would have prevented 10-16% of a sample of closely studied fatal accidents. In other words they will make cycling safer but are not a pancea. Things like route choice and rider skill are far more important.


That TRL report and 10-16% statistic has a serious problem. The report basically says after reviewing the evidence that the effectiveness of helmets is unknown. They then say but lets assume anyway they are 50% effective and if they were, they would prevent 10-16% of accidents. They then headline that figure. So a conclusion which is not based on any evidence whatsoever.


They suggest helmets would prevent 10-16% of fatalities not accidents.

While I agree their assumption of 50% effectiveness is open to question it is a reasonable ballpark figure. The fact that using the assumption of 50% effectiveness only saves 10-16% of fatalities puts the helmet propoganda into perspective and proves that helmet wearing can only ever be a small part (if any) of the answer to increasing cycling safety.

Actually the TRL report didn't claim 50% overall effectiveness - that 50% assuption was for ground impacts. They assumed 10-30% for vehicle impacts. To clarify for anyone who hasn't read the full TRL report - part of it (page 48) looked in detail at 113 cycle fatalities to see whether helmets might have prevented them.

44 had fatal injuries elsewhere than the head. So obviously none of them would have been prevented.
3 Had fatal head injuries despite wearing a helmet.
11 were caught under or run over by a vehicle, so none would have been prevented.
7 had fatal head injuries from multiple causes so none would have been prevented.
31 had head injuries due an impact from a vehicle. The assumption was 10-30% fatalities may have been prevented.(between 3 and 9 of the 113)
And finally 17 had head injuries due to an impact with the ground. This is where the authors assumed 50% would have been prevented by helmet wearing. Or 9.

So the total estimated fatalities saved was 12-18 or 10-16%

I've looked at figures with different assumption for ground impacts (Keeping the vehicle impact fatals at between 3 and 9 lives saved). First, assuming 75% (12) of the 17 ground impact fatals were prevented would give 15-21 lives saved overall. Or 13-19% effectiveness. Assuming helmets were 25% effective for ground impacts saving 4 out the 17 of those deaths. Overall figures are now between 7 and 13 fatalities prevented. An overall effectiveness of between 6% and 12%

While the 50% assumption is open to debate the more relevant thing IMO is that no matter what effectiveness you assume for ground impact protection in the vast majority of fatal accidents a helmet won't save anyone's live.

Then of course the report does not estimate the increases in numbers of accidents involving helmeted cyclists due to risk compensation and by drivers perceiving them as protected and taking less care.
No one believes more firmly than Comrade Napoleon that all animals are equal. He would be only too happy to let you make your decisions for yourselves. But sometimes you might make the wrong decisions, comrades, and then where should we be?

TonyR
Posts: 5390
Joined: 31 Aug 2008, 12:51pm

How to ask a helmet question?

Postby TonyR » 10 May 2011, 12:17pm

irc wrote:
They suggest helmets would prevent 10-16% of fatalities not accidents.


You are correct.

While I agree their assumption of 50% effectiveness is open to question it is a reasonable ballpark figure.


Why is 50% a reasonable ballpark figure? Why not 0% or -10%? The report itself admits the effectiveness is unknown. The only basis for assuming 50% is that it fits with their preconceptions.

Actually the TRL report didn't claim 50% overall effectiveness - that 50% assuption was for ground impacts. They assumed 10-30% for vehicle impacts.


I was trying to keep it simple but you are correct that they do assume two different effectiveness rates.

alicej
Posts: 1301
Joined: 14 Oct 2010, 10:16pm
Location: Leeds, West Yorkshire

Re: How to ask a helmet question?

Postby alicej » 10 May 2011, 1:01pm

Just looking in to let you all know I haven't abandoned this thread yet :) just really busy today.

Some interesting stuff here and links to things that I'll find time to read through properly. Thanks for keeping it so civilized!
May get another chance to look in later on today so feel free to keep it coming.

Ellieb
Posts: 845
Joined: 26 Jul 2008, 7:06pm

Re: How to ask a helmet question?

Postby Ellieb » 10 May 2011, 1:29pm

The point is alicej, if the issue was in any way clear cut, we wouldn't be having these debates. Perhaps more importantly, even if the stats were agreed by all (& it is incredibly difficult to get an unbiased source for them) would you be able to tell how it imapcts on your personal risk level? There are so many variables involved: Your experience, your riding style, where you ride, when you ride, your own attitude to risk etc etc. As things stand you have almost no way of 'scientifically' working out the facts. If the studies were absolutely unequivocal then you could probably say that individual factors might not make a difference. But that isn't the case. I personally, on an individual basis think it is worth wearing a helmet, because I can see it does provide a form of protection. Whether it would save my life? Who knows. On a population basis is it safer? It depends how much you choose to believe wearing a helmet puts people off in the UK. I don't reallty find wearing a helmet to be a problem, so for me, I might as well wear one. On this particualr forum, you will find I am in a minority, but that wouldn't necessarily be the case if you went elsewhere on the internet.

User avatar
hubgearfreak
Posts: 8210
Joined: 7 Jan 2007, 4:14pm

Re: How to ask a helmet question?

Postby hubgearfreak » 10 May 2011, 1:36pm

Ellieb wrote:that wouldn't necessarily be the case if you went elsewhere on the internet.


out on the road, however :wink: