Crash and helmet

For all discussions about this "lively" subject. All topics that are substantially about helmet usage will be moved here.
DevonDamo
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Joined: 24 May 2011, 1:42am

Re: Crash and helmet

Post by DevonDamo »

mattheus wrote: 22 Sep 2022, 10:32amDo you have a citation - on THIS thread - for your first claim?

"... some of the assertions being made, e.g. that if your head is about to be hit hard by a blunt or sharp object, then having a helmet on your head won't offer any protection"
Who said this?
(I'm choosing not to quote the individual posts, as that would send each poster a notification which increases the likelihood that we'll end up regurgitating dormant discussions. I've stated the page number so you can find them.) The following posts in this thread have questioned whether helmets provided any benefit in cases where the impact had enough force to significantly damage the helmet itself. My point is that Joe Public would read this type of thing and say "what sort of person would not strongly prefer a helmet to a bare head when being exposed to such a high impact?" which detracts from your credibility and distracts from the very strong argument that can otherwise be made against mandatory helmet use:

“And you got concussion anyway, which is a failure too. So the helmet could have provided some benefit, but the evidence is far less impressive than if neither of those things had happened. And it also fits with no benefit at all.” Page 2. 7th post, made in response to someone recounting their experience of an off-road impact with a metal post which resulted in their helmet being smashed in two.

“Until you remember that all except a few full face MTB helmets are only tested for standing falls onto flat surfaces or kerb edges. The old test of falling onto a stone has gone. Other things like typical rough surfaces have never been tested. And if a helmet hits something like a stone, or walnut, it may well fail and split. Just as well none of the helmets talked about here split, isn't it?” 2nd page, 9th post, made in response to my assertion that the helmet’s role in the above accident was clearly better than nothing.

“I see a LOT of pictures of cracked helmets - so remember this is barely absorbing any energy at all. Think of car CRUMPLE zones - they are not made out of brittle materials, deliberately!” You, page 8, referring to the same incident whereby the helmet smashed after impact with a metal post.

“I'll try to put this simply; if you crack a protective helmet, it has not reduced* the decelerations involved. It is not crumpling. A thick cushion would be better protection. In fact thick cushions would be good protection for your head against blunt trauma, even though I haven't seen any tests for me to quote at you :) *Or perhaps only negligibly!” You, page 8

“You can flash your credentials all you like: I do know how energy conversion works (you're not the only cyclist that went to school my friend), and I know that a cracked helmet isn't doing a lot for you.” You, page 10.
Mike Sales
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Re: Crash and helmet

Post by Mike Sales »

The sort of evidence which convinces me that helmets are irrelevant, and which I think that I have repeated several times on this forum, is the real life results where helmets are seen as the answer to high cyclist casualty rates, and are mandated or intensively encouraged.
The mandation or high wearing rate countries remain high casualty rate countries.
It is understandable that cyclists resort to helmets in these dangerous jurisdictions, but they remain rather more dangerous than the UK.
Other countries have tried other ways of making cycling safe, and are rather safer than us per mile cycled.
Do I need to list the countries and their approach to cycling safety?
Edited to add that the countries in which helmet wearing is rare, are those where cycling is common and safe. Whereas the countries where wearing rate is high or mandated are those where cycling is uncommon, and often confined to "road warriors" or sporting cyclists. If we want cycling to contribute to a low carbon future, we need cycling to be seen as a routine way of getting about.
It occurs to me that there is an analogy with trying to move towards net zero CO2. Individual actions will not to the trick: we need governmental action.
I have no statistical training, or inclination to search the evidence, so I have to rely on experts like Spiegelhalter and Goldacre, who I have also referred to many times.
For others, this is an explicitly political matter, where an emphasis on helmets reflects a seductively individualistic approach to risk management (or even “victim blaming”) while the real gains lie elsewhere. It is certainly true that in many countries, such as Denmark and the Netherlands, cyclists have low injury rates, even though rates of cycling are high and almost no cyclists wear helmets. This seems to be achieved through interventions such as good infrastructure; stronger legislation to protect cyclists; and a culture of cycling as a popular, routine, non-sporty, non-risky behaviour.

In any case, the current uncertainty about any benefit from helmet wearing or promotion is unlikely to be substantially reduced by further research. Equally, we can be certain that helmets will continue to be debated, and at length. The enduring popularity of helmets as a proposed major intervention for increased road safety may therefore lie not with their direct benefits—which seem too modest to capture compared with other strategies—but more with the cultural, psychological, and political aspects of popular debate around risk.
So you see that I require much better evidence that helmet promotion or mandation are the way to go.
The real world experience shows that helmets are irrelevant, and serve as a diversion from the measures which actually produce safe roads for cycling.
Some object that evidence from mandation countries is not relevant to voluntary wearing, as if helmets fail to work for cyclists who are compelled to wear them!
dmrcycle
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Joined: 20 Sep 2022, 12:16am

Re: Crash and helmet

Post by dmrcycle »

mattheus wrote: 22 Sep 2022, 9:57am

*EDIT: I forgot one, sorry! I forget momentum, I hope (s)he forgives me. As you will know from your collision studies, momentum is conserved even when energy is being chucked around into noise and heat etc.)
Here is where understanding is flawed. You are totally incorrect about momentum. Momentum is not conserved if energy is lost in heat, noise etc. Thats the point of the helmet. Newtons 1st law is explicit its for a closed system not allowing for losses of energy. If you had conservation of momentum for a helmet impact we would be bouncing down the road. The helmet absorbs the momentum (speed x mass) and converts it to heat/sound in breaking the bonds in the helmet when it shatters. In most materials shattering and breaking bonds actually absorbs more energy than deformation (aka your crumple zones).
buryman
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Re: Crash and helmet

Post by buryman »

Oh dear, how wrong can one be.
mattheus
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Re: Crash and helmet

Post by mattheus »

DevonDamo wrote: 22 Sep 2022, 12:14pm
mattheus wrote: 22 Sep 2022, 10:32amDo you have a citation - on THIS thread - for your first claim?

"... some of the assertions being made, e.g. that if your head is about to be hit hard by a blunt or sharp object, then having a helmet on your head won't offer any protection"
Who said this?
(I'm choosing not to quote the individual posts, as that would send each poster a notification which increases the likelihood that we'll end up regurgitating dormant discussions. I've stated the page number so you can find them.) The following posts in this thread have questioned whether helmets provided any benefit in cases where the impact had enough force to significantly damage the helmet itself. My point is that Joe Public would read this type of thing and say "what sort of person would not strongly prefer a helmet to a bare head when being exposed to such a high impact?" which detracts from your credibility and distracts from the very strong argument that can otherwise be made against mandatory helmet use:

“And you got concussion anyway, which is a failure too. So the helmet could have provided some benefit, but the evidence is far less impressive than if neither of those things had happened. And it also fits with no benefit at all.” Page 2. 7th post, made in response to someone recounting their experience of an off-road impact with a metal post which resulted in their helmet being smashed in two.

<snipped your other examples for brevity>
Damo,
I really appreciate your lengthy editing/collating here, so it pains me to disagree with the main thrust; NOT ONE OF THEM says a helmet offers no protection.
I was very careful with my wording in the posts you quote, in addressing specific aspects. I stand by what I wrote, and in no case do I say " ... a helmet offers no protection."


If we look at the post Page 2 7th post [not by me], the poster says

"... the helmet could have provided some benefit, but the evidence is far less impressive than if neither of those things had happened"

So again, it's quite clear that (s)he did NOT write " ... a helmet offers no protection."
mattheus
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Re: Crash and helmet

Post by mattheus »

buryman wrote: 22 Sep 2022, 2:55pm Oh dear, how wrong can one be.
I blame the teachers :wink:
mattheus
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Re: Crash and helmet

Post by mattheus »

Jdsk wrote: 22 Sep 2022, 12:09pm
Jdsk wrote: 22 Sep 2022, 11:11am
mattheus wrote: 22 Sep 2022, 11:09am ...
You're reading this thread, right? We have highly vocal helmet compulsion fans right here...
...
Please could you give an example of that in this thread.
mattheus wrote: 22 Sep 2022, 12:05pm ...
It's this one:
viewtopic.php?p=1724500#p1724500
Thanks.

That isn't in this thread.

Jonathan
I know - please reread my post, I think you'll find it's accurate.
DevonDamo
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Re: Crash and helmet

Post by DevonDamo »

mattheus wrote: 22 Sep 2022, 2:57pmI really appreciate your lengthy editing/collating here, so it pains me to disagree with the main thrust; NOT ONE OF THEM says a helmet offers no protection.
You win. You didn't say 'no protection.' You said:
  • "barely absorbing any energy at all."
  • "it has not reduced* the decelerations involved. *Or perhaps only negligibly!"
  • "I know that a cracked helmet isn't doing a lot for you"
Neither did the other poster you've defended, however you forgot to quote the second part of his statement:
  • "And it also fits with no benefit at all"
So accept my sincere apologies for my outrageous misinterpretation of your statements. I feel it's only right for you to set the record straight here: how much protection do you believe the helmet offered in the metal-post-whacking incident?

(I'm looking forward to seeing what choice of words you use. You definitely can't say 'a lot' and you can't now say 'none' but you're going to have to back up what you've said in your other posts by saying something like 'almost none.' Might look like you're splitting hairs in your post above?)

For the record, my advice to everyone caught in this dilemma is simple: you don't need to die on this 'helmets don't protect you when you get smacked on the head" hill. It won't get you anywhere with the anti-cycling lobby other than calls to change standards to require heavier, wider, hotter etc. helmets. Instead, all you need to do is say: "yes, a helmet will help if you're going to whack your head, but (1) any safety benefit from helmet use pales into insignificance when compared with the provision of decent cycling infrastructure and (2) mandatory helmet use will result in more deaths and serious illness s due to the resultant reduction in cycling and those situations where the helmets themselves can result in an injury."
dmrcycle
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Joined: 20 Sep 2022, 12:16am

Re: Crash and helmet

Post by dmrcycle »

Some research
https://www.sciencedirect.com/science/a ... 7818300810
https://academic.oup.com/ije/article/48 ... ogin=false

In my own personal experience I wont go cycling unless I have a helmet, so far from discouraging cycling the use of a helmet in my case encourages it. Encouraging helmet use also ensures they remain cheap and easily available to those who are sensible enough to want to use one.

Having had similar impacts to hard earth falling off a mountain bike on the trail with and without a helmet I can tell you with the helmet (which shattered) the trauma was much less. No concussion or headache or lump/bruise and I didn't even feel the impact on my head as the polystyrene cracked and did its job and absorbed the energy of impact and also ensured it was not a blunt impact at a point of contact but spread the forces. It was nice also that the helmet manufacturer gave me a free replacement.
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horizon
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Re: Crash and helmet

Post by horizon »

dmrcycle wrote: 22 Sep 2022, 6:59pm Some research
https://www.sciencedirect.com/science/a ... 7818300810
https://academic.oup.com/ije/article/48 ... ogin=false

In my own personal experience I wont go cycling unless I have a helmet, so far from discouraging cycling the use of a helmet in my case encourages it.
In my own personal experience, I wouldn't go cycling if I felt I ought to wear one. I'm just not into high risk activities.

If it were compulsory, I would still cycle as I would still deem it safe enough. And that doesn't mean that I think cycling is 100% safe but to the extent that it isn't, I don't see a helmet helping much. And I also accept that I might be wrong.
When the pestilence strikes from the East, go far and breathe the cold air deeply. Ignore the sage, stay not indoors. Ho Ri Zon 12th Century Chinese philosopher
mattheus
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Re: Crash and helmet

Post by mattheus »

DevonDamo wrote: 22 Sep 2022, 5:02pm For the record, my advice to everyone caught in this dilemma is simple: you don't need to die on this 'helmets don't protect you when you get smacked on the head" hill.
Yes, I agree - and that's why I don't say it! Simples!
DevonDamo wrote: 22 Sep 2022, 5:02pm ...
It won't get you anywhere with the anti-cycling lobby
Are they represented on this thread? It seemed to me that I was responding to cyclists who promote helmets. Can you point out the anti-cycling lobbyists on this thread?
DevonDamo
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Re: Crash and helmet

Post by DevonDamo »

Thank **** for that! We finally appear to have emerged from the dark forest of bickering and point-scoring into the sunlit uplands of agreement.

I'm glad we're in agreement that a helmet will help if you're going to take a bash on the head anyway. Common sense isn't it? And the great thing is that acknowledging this fact saves you from an unwinnable argument and doesn't stop you from opposing mandatory helmet laws.

And I don't know where that suggestion came from, but I also agree with you: the anti-cycling lobby aren't represented on this thread - not as far as I've seen, anyway.
mattheus
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Re: Crash and helmet

Post by mattheus »

DevonDamo wrote: 23 Sep 2022, 9:52am We finally appear to have emerged from the dark forest of bickering and point-scoring into the sunlit uplands of agreement.
Sounds very dull ....
DevonDamo
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Re: Crash and helmet

Post by DevonDamo »

mattheus wrote: 23 Sep 2022, 11:25am Sounds very dull ....
NO IT DOESN'T!!!!!!

(Sorry I'll stop now.)
Mike Sales
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Re: Crash and helmet

Post by Mike Sales »

axel_knutt wrote: 12 Aug 2022, 10:00pm I wrote off a car in a crash I wouldn't have survived without a seatbelt, but that doesn't prove that there are more alive with seatbelt legislation than there would have been without it.
John Adams reviews the effects of seat belts.

http://www.john-adams.co.uk/2013/03/24/the-biggest-lie/
Significantly the Significance article did not make it into the Review's list of key references on seat belts. A significant omission because the authors, all defenders of the seat belt law, acknowledge an effect of the law of important consequence to vulnerable road users. They say the clear reduction in death and injury to car occupants is appreciably offset by extra deaths among pedestrians and cyclists.
seatbelts2.jpg
Seat belts transferred risk to the more vulnerable.

Significance is the journal of the Royal Statistical Society.
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