Anybody not wear a helmet? Discuss....

linsen

I wear a helmet because quite often when I get up and go out for a ride my hair is sticking up. By the time I then arrive at the pub, or tea shop, my hair is acceptable enough to be seen in public.

jedster

From the above we don't know if your head would have hit anything at all if you hadn't been wearing a helmet

oh come on!

I have slid my helmet across the road in other falls - you get a light scuffing. This is what happens in a fall when you would not have hit a bare head.

To hit a helmet on the ground hard enough to crush it, you can be absolutely confident that your bare head would have hit the ground. And hard.

On the population studies, I share your view that the lack of evidence really questions the value of helmets - I'm not someone who prefers anecdotes to statistics. The problem that I have with the research is that it seems to focus on fatalities. I'm not sure that a helmet is likely to save your life in a really bad accident (I would expect some cases but not all that many). I do think that it will usefully mitigate more moderate incidents.

In my case, the helmet didn't stop me from going to casualty and from a blow to the head being recorded. Assume for the moment that the helmet turned a nasty concussion into a minor headache - how would my incident show up in statistics?

J

always_tyred

WGWarburton wrote:

You do seem to be pressuring LiT.

I think that LiT will withstand the pressure. In addition, simply taking the position that I believe that helmets are worthwhile is no more pressurising, less I'd say, than the more bald peer pressurising that helmets are ugly, uncomfortable and useless and pro-riders hate them and they are our heroes.

always_tyred

WGWarburton wrote:

jedster,

There are any number of anecdotes like this, but no real evidence.

From the above we don't know if your head would have hit anything at all if you hadn't been wearing a helmet, nor whether your injuries would have been worse- plenty of people have come off their bikes under similar circumstances and not hit their head at all- maybe the headache was caused by the impact of the helmet on the road. Or maybe you would have died or been seriously brain injured if you hadn't been wearing it.

Population studies would surely show an improvement in KSI stats if helmets worked as they are purported to do.

I really struggle to get away from this- it's very counterintuitive and I worry that there's something sinister going on (eg increased risk of serious injury along with reduction in rate of relatively minor ones).

As I said earlier, I would really like to see some evidence that helmets actually work, in the absence of that it looks very like faith based reasoning.

Cheers,
W.

Look, I'll assume that you believe that wearing a helmet and smashing your head on the ground will have a different result to wearing a cloth cap and smashing your head on the ground, and that you are really concerned not in individual incidents, but the overall contribution of those incidents in the grand scheme of cycle safety.

I doubt that any of us are capable of understanding or truly appreciating the merits and shortcomings of the statistics. The fact that different statisticians come up with different conclusions is interesting. It rather suggests that the raw data is poor.

My concern over the population "studies" is that they aren't studies; they are highdsight analyses of data that is acquired for all incidents of all types in the general population. Nowhere have I seen any actual study of significant size which has been designed from the outset to probe cycle safety. The closest one can get to some form of designed scientific experiments are similar to (and including) the very safety tests so derided by the anti-helmet lobby. Those test seek to take the circumstances of blunt force trauma into a controled environment and measure them. The anti-helmet people then turn this around and say, well, its not in the real world so it doesn't mean anything. What, exactly, would be satisfactory then?

The very statement, "What you would expect from...." is an absolute red flag to suggest that an analysis is preconceived. Of course, no science in practice is uncontaminated by one's notion of how it ought to turn out, but the analysis of coarse data, in hindsight, is very very trecherous territory, and that it all we have. Frankly, there aren't enough cyclists and cycle safety is not important enough to justify the effort of having a large number of clinicians in a large number of hospitals for a long period of time record data relating to cycle accidents in any way differently from data relating to dropping HP sauce bottles on one's foot.

Therefore, I think it is only safe to say that it would be wrong to draw too many firm conclusions from available studies either way.

If you think about it, analyses of this type (i.e. of general A&E admissions information) gives rise to humourous stats indicating that one's toilet is more dangerous than a motor vehicle. I've suggested earlier in this thread that data that is so coarse (essentially box ticking, or keyword searching - e.g. injury = Y, toilet = Y) is fairly unhelpful.

So, after lunch, be careful in the Gents, okay?

il_principe

biondino wrote:

Once you get enough anecdotes about helmets doing their job, you have to start thinking there may be something to it, Buns. And there have been dozens on here alone, so by all means start on the prudent assumption that some are overstated or plain wrong but at some point you've got to take your head out of the sand.

What there ISN'T any evidence of - and I mean not one single example in every single helmet thread I've read - is helmets increasing injuries. Not one. There's a theoretical argument that in a very small window between serious injury and death, a helmet might exacerbate damage - and yet not one of the naysayers has found a single example.

As for jedster's accident, you're suggesting that if he hadn't been wearing a (crushed) helmet he might not have hit the road at all? Really? I dunno about your neck muscles but the extra inch breathing space not wearing a helmet gives doesn't sound enough to be able to bring however many pounds of skull, flesh and brain to a complete stop in a 20mph accident.

The depressing thing is that you're one of the most knowledgeable and wise posters on here and yet when someone gives you the CLEAREST POSSIBLE evidence - and yes it's anecdotal but I'm not sure an anecdote could be more cut and dried - you stick your fingers in your ears and start shouting "I'm not listening". It really doesn't help the rest of your argument, you know.

Sorry Blondie but anecdotes do not = evidence. It's very easy to say "if it wasn't for the helmet" but without evidence it's pointless. I might as well attribute the fact that I've walked away from my two crashes without serious injury to divine intervention. Just because a helmet was dinged, doesn't mean your skull would be if you were sans helmet. Incidentally I slipped down my stairs last night (thank you slippery cycling shoes) and banged my head - perhaps I should wear a helmet indoors?

Most BMW drivers I see drive like morons, does this mean that the majority of beemer drivers are morons - well no, but according to your reasoning it does. Lots of people on here post about BMW drivers being particularly bad, again this does not count as evidence.

As for the broken helmet argument that features in so many anecdotes:

Helmets work by the outer shell keeping the polystyrene in place whilst it absorbs the deceleration by being crushed. Counter-intuitively if the shell breaks in the initial contact the total energy absorbed is a lot less: a broken helmet is one that didn't work. This means above about 12.5mph the helmet has little effect; certainly it won't reduce a crash at, say, 30mph by an amount equivalent to crashing at 12.5mph.

If you really want to wear a helmet that will actually make a difference wear a motorcycle helmet. They are designed to protect the head in higher speed impacts (i.e above 12-15 mph) and collisions with other vehicles, cycle helmets aren't, can't and won't. Of course if you wear a motorcycle helmet your head will boil.

At the end of the day cycling is a safe activity, stats I've read suggest that walking in London is just if not more dangerous than cycling.

wgwarburton

Biondino:

> The depressing thing is that you're one of the most knowledgeable and wise posters on here and yet when someone gives you the CLEAREST POSSIBLE evidence - and yes it's anecdotal but I'm not sure an anecdote could be more cut and dried - you stick your fingers in your ears and start shouting "I'm not listening". It really doesn't help the rest of your argument, you know.

I'm listening. I'm just not hearing any evidence, or any explanation of why it is that so many people, who've spent so much money and tried so hard have failed to prove that helmets actually work at a population level.

It doesn't matter. Maybe my skepticism is as irrational as the helmet wearers faith,it'd just be nice if the people who advocate them could produce something other than "common sense" and anecdotes to support their view.

...and there's stll the point that cycling isn't actually that dangerous. We really should try and remember that one, because the argument about whether or not helmets are effective is actually pretty academic.

Cheers,
W.

prawny

Motorcyclists still die of head injuries though (RIP Jonesy) where to draw the line.

If your times up your times up, wear a helmet if you dont want to bump your head, if you don't want to die dont be born.

always_tyred

WGWarburton wrote:

...and there's stll the point that cycling isn't actually that dangerous. We really should try and remember that one, because the argument about whether or not helmets are effective is actually pretty academic.

As I say, you have evidence, you just don't like the answer.

If you say, "Give me evidence that the brakes of my car work" and I come back with measurements taken of a braking system recorded in a lab, of reducing the rotational inertia of a predetermined mass, calculated to be the equivalent of a vehicle, you'd say, "Oh, right, so that means that the braking system is adequate."

Given equivalent data of the effective reduction of peak force from impact to a head shaped object, you say, "well it might not happen like that so there".

I simply don't get it. Its not blind faith. We say "some" you hear "all" and think "none".

Cycling is approximately twice as dangerous as driving. I can't remember if that's per hour or per mile (hour, I think).

A given cyclist can be far safer on their bike than a given motorist is in their car. But taking the cycling population and the driving population as a whole, this isn't the case. You like your population studies right, WG?

DonDaddyD

Hi,

I've hit my head on the road twice without a helmet and once with a helmet. The first time I did it without a helmet I woke up to find people around me and the second time without a helmet I did it I woke in the recovery position with people around me. When I did it with a helmet, far worse fall, I got up and walked away. So in my experience I'd prefer tor hit my head on a curb with a working helmet as opposed to without one.

I haven't read the thread. Is there any definitive evidence that a helmet will increase the chances of injury while wearing it. Helmets weren't designed to protect me from all possible head injuries but wearing a helmet increases my safety and while it continues to increase (not decrease) my safety on a realistic and practical level, I'll always wear one.

Incidentally I was watching the Tour of Ireland. This guy skidded, came off the bike and slid down the road on his head for sometime. Given the speed, there is no way his head wouldn't have hit the ground. The helmet (i) taking the impact and (ii) protecting his head from the tarmac meant he could continue the race. Now a completely different type of collision may have resulted in him not being able to continue the race. A different type of impact may have resulted in the loss of his life but that doesn't mean wearing a helmet is any less safe than not wearing one in fact wearing a helmet that day increased his levels of safety.

So until someone can definitively prove that wearing a helmet actually decreases safety I'm not really seeing any arguments that can support the notion of not wearing one is better than wearing one.

However wearing or not wearing one remains the decision of the individual.

greg66_tri_v2.0

There is an end point in sight to this debate.

The non-helmet wearers will all eventually get their heads squashed, mashed, crushed, sliced a la the blancmange two-step.

Thus, their insidious stain on the gene pool will slowly be erased, leaving all children happily wearing helmets for life on the unimpeachable advice of their helmet wearing parents.

Easy.



As to the evidence-wanters, how about we do some field tests? Blindfold them with two blindfolds (I think that's what they do in double blind testing), put a helmet on them, and push them into a fast moving piece of traffic.

Pick them up, and repeat without the helmet.

Ta-dah! Instant empirical evidence.



Why has it taken 19 pages for me to think of this?

always_tyred

Greg66 wrote:

There is an end point in sight to this debate.

The non-helmet wearers will all eventually get their heads squashed, mashed, crushed, sliced a la the blancmange two-step.

Thus, their insidious stain on the gene pool will slowly be erased, leaving all children happily wearing helmets for life on the unimpeachable advice of their helmet wearing parents.

Easy.



As to the evidence-wanters, how about we do some field tests? Blindfold them with two blindfolds (I think that's what they do in double blind testing), put a helmet on them, and push them into a fast moving piece of traffic.

Pick them up, and repeat without the helmet.

Ta-dah! Instant empirical evidence.



Why has it taken 19 pages for me to think of this?

God, I thought you were going to mention Darwin for a moment there.

biondino

WGWarburton wrote:

Biondino:

It doesn't matter. Maybe my skepticism is as irrational as the helmet wearers faith,it'd just be nice if the people who advocate them could produce something other than "common sense" and anecdotes to support their view.

At least the pro-helmet lobby HAS "common sense"* and anecdotes. That's 1-0 to them I fear.

*yes, I know, "common sense" is often anything but. In this case, though, I think they've got it right.

Jash - in all the times I've fallen off my bike I've never hit my head, which is great, but I don't think I'd have hit my head even if I'd been wearing a helmet. So no difference. When I *do* have an accident where I hit my head, I'd very much like to be wearing a helmet please.

Also, jedster's helmet was crushed, not split.

greg66_tri_v2.0

Always Tyred wrote:

Greg66 wrote:

There is an end point in sight to this debate.

The non-helmet wearers will all eventually get their heads squashed, mashed, crushed, sliced a la the blancmange two-step.

Thus, their insidious stain on the gene pool will slowly be erased, leaving all children happily wearing helmets for life on the unimpeachable advice of their helmet wearing parents.

Easy.



As to the evidence-wanters, how about we do some field tests? Blindfold them with two blindfolds (I think that's what they do in double blind testing), put a helmet on them, and push them into a fast moving piece of traffic.

Pick them up, and repeat without the helmet.

Ta-dah! Instant empirical evidence.



Why has it taken 19 pages for me to think of this?

God, I thought you were going to mention Darwin for a moment there.

Yeah, well I thought about it. But I decided to play a straight bat and keep it factual. No sense getting everyone inflamed...

lost_in_thought

Hmmmmm, I agree that cycling is relatively safe, but I really can't see any strong arguments that it's better not to wear a helmet than to wear a helmet.

However, despite the pressure, no matter what all y'all say I still ain't wearin' one.

I laugh in the face of danger. Ha.

biondino

Greg, I dunno if you remember but I suggested to erstwhile poster meanwhile (I think it was) that he and I should do a lab-controlled test where I wore a helmet, he didn't, and we were both hit on the head with a blunt object with increasing force and our reactions were measured. He didn't fancy it, for some reason.

il_principe

I've come off my bike twice. Both times during my helmet wearing days. I hit my head once, but it was on the chin and nose, the helmet made sod all difference. I'm not convinced there are many (if any) scenarios when I'd be travelling at or below effective helmet speed, come off and manage to hit my head - not as a road cyclist (and I don't MTB). So i don't bother with one. I prefer not wearing one, and I'm not going to diminish the pleasure that cycling gives me in order to appease the hand wringers.

Incidentally my non cycling girlfriend used to give me grief for not wearing a helmet. I invited her to read around the subject (and did not provide her with any links at all), she's stopped bothering me about it now...

always_tyred

biondino wrote:

Also, jedster's helmet was crushed, not split.

Yes, it should be pointed out that from mere visual inspection of a crushed, cracked helmet, it is not possible to determine to what degree the crushing had occurred before the splitting commenced. Thus, a cracked helmet does not necessarily infer that the helmet failed to function.

steve-m

Always Tyred wrote:

There are a myriad of other materials available. I'm not a materials specialist, but were you to plot density of a foam vs. its shock absorbancy, not all materials would fall on a straight line (which in case you aren't following is the conclusion one would draw from your argument). Indeed, polystyrene is a foam, but the stuff they use in helmets is compromised since it is extruded as beads, and the weak point in the system is the association between the beads, not the shock absorbancy of the beads themselves.

Basic physics. Even if a super magic material were to exist, your brain still still going from 12mph to Zero in an short amount of time, do that to blancmange. Shock absorbency is irrelevant.

http://subtlebraininjury.com/shear1.html

Diffuse axonal injury can occur without any direct impact on the head, as it requires only the condition of rapid acceleration/deceleration such as takes place in whiplash injuries due to acceleration/deceleration resulting in rapid flexion-extension movement of the neck.

However, the likelihood of significant diffuse axonal injury increases when the head hits something, such as a windshield, as the change in momentum is greater because of the sudden stopping of the head. But in a shearing mechanism, it is not the contact phenomenon which cause the injury, but the change in momentum.

So no magic material is going to stop a change in momentum.

I am open to contra POV - and calling "rubbish" is not an answer.

always_tyred

jashburnham wrote:

I've come off my bike twice. Both times during my helmet wearing days. I hit my head once, but it was on the chin and nose, the helmet made sod all difference. I'm not convinced there are many (if any) scenarios when I'd be travelling at or below effective helmet speed, come off and manage to hit my head - not as a road cyclist (and I don't MTB). So i don't bother with one. I prefer not wearing one, and I'm not going to diminish the pleasure that cycling gives me in order to appease the hand wringers.

Incidentally my non cycling girlfriend used to give me grief for not wearing a helmet. I invited her to read around the subject (and did not provide her with any links at all), she's stopped bothering me about it now...

I just don't get this. you use anecdote to justify not wearing one, stating "I'm not sure there is any circumstances where...." but throw out as invalid anecdotal evidence demonstrating that indeed, it is possible to bang your head when cycling.

I fell off once, slid along a grass verge and smashed the TOP of me head against a tree. I knocked myself out. I have worn a helmet ever since.

I also came off as a kid and knocked myself out with a blow to the temple. Okay, the bike I was riding was about a 48cm frame and had 3 gears, but I'm pretty sure it qualified as a road bike and was being ridden on the road.

Sorry those are only anecdotes.

greg66_tri_v2.0

biondino wrote:

Greg, I dunno if you remember but I suggested to erstwhile poster meanwhile (I think it was) that he and I should do a lab-controlled test where I wore a helmet, he didn't, and we were both hit on the head with a blunt object with increasing force and our reactions were measured. He didn't fancy it, for some reason.

Great minds, Blondie, great minds

I've probably got some 4 by 2 lying around at home...

steve-m

Always Tyred wrote:

If you think about it, analyses of this type (i.e. of general A&E admissions information) gives rise to humourous stats indicating that one's toilet is more dangerous than a motor vehicle. I've suggested earlier in this thread that data that is so coarse (essentially box ticking, or keyword searching - e.g. injury = Y, toilet = Y) is fairly unhelpful.

LOL, also most accidents occur in the home, I myself was rushed to A&E and in theatre for 6 hours due to an accident involving a toilet.

A helmet would not have helped, - a shower mat would.

DonDaddyD

I just don't get it.

Please someone with a brain larger than mine explain.

There are instances when wearing a helmet is going to be more beneficial than not wearing a helmet.

Are there any or as many instances when not wearing a helmet is more beneficial than wearing one.

If not, then why choose not to wear a helmet when wearing one most certainly increases your safety in some instances.

always_tyred

steve-m wrote:

Always Tyred wrote:

There are a myriad of other materials available. I'm not a materials specialist, but were you to plot density of a foam vs. its shock absorbancy, not all materials would fall on a straight line (which in case you aren't following is the conclusion one would draw from your argument). Indeed, polystyrene is a foam, but the stuff they use in helmets is compromised since it is extruded as beads, and the weak point in the system is the association between the beads, not the shock absorbancy of the beads themselves.

Basic physics. Even if a super magic material were to exist, your brain still still going from 12mph to Zero in an short amount of time, do that to blancmange. Shock absorbency is irrelevant.

http://subtlebraininjury.com/shear1.html

Diffuse axonal injury can occur without any direct impact on the head, as it requires only the condition of rapid acceleration/deceleration such as takes place in whiplash injuries due to acceleration/deceleration resulting in rapid flexion-extension movement of the neck.

However, the likelihood of significant diffuse axonal injury increases when the head hits something, such as a windshield, as the change in momentum is greater because of the sudden stopping of the head. But in a shearing mechanism, it is not the contact phenomenon which cause the injury, but the change in momentum.

So no magic material is going to stop a change in momentum.

I am open to contra POV - and calling "rubbish" is not an answer.

Basic physics.

Go get some lego.

Take 10 bricks. Pile them up. How high are they? 10 bricks high. Okay, so that's how high a force of 1 brick duration is, corresponding to a momentum of 10 bricks.

Okay, now take your 10 bricks. Line them up. How high are they? 1 brick. Okay, so that's how high a force is, corresponding to the same 10 brick momentum, over a period of 10 bricks.

There, my friend, is the basic principle of the protective helmet, deformable crash structures in cars, your airbag, and hitting you over the head with a rubber mallet. The idea is that the helmet converts what might otherwise be a 1 brick long, 10 brick high impact into a 10 brick long, 1 brick high accident. but they might only convert the impact into a 2 brick high, 5 brick long impact, but i'll take that.

As for rotational brain injury. It is a known phenomenon. It is not clear to anyone, including you, that it is a significant issue in cycling accidents. It might be, in which case more compact, smoother helmets would be advisable.

always_tyred

steve-m wrote:

Always Tyred wrote:

If you think about it, analyses of this type (i.e. of general A&E admissions information) gives rise to humourous stats indicating that one's toilet is more dangerous than a motor vehicle. I've suggested earlier in this thread that data that is so coarse (essentially box ticking, or keyword searching - e.g. injury = Y, toilet = Y) is fairly unhelpful.

LOL, also most accidents occur in the home, I myself was rushed to A&E and in theatre for 6 hours due to an accident involving a toilet.

A helmet would not have helped, - a shower mat would.

That's anecdotal. It didn't happen. Home is safe.

il_principe

Always Tyred wrote:

jashburnham wrote:

I've come off my bike twice. Both times during my helmet wearing days. I hit my head once, but it was on the chin and nose, the helmet made sod all difference. I'm not convinced there are many (if any) scenarios when I'd be travelling at or below effective helmet speed, come off and manage to hit my head - not as a road cyclist (and I don't MTB). So i don't bother with one. I prefer not wearing one, and I'm not going to diminish the pleasure that cycling gives me in order to appease the hand wringers.

Incidentally my non cycling girlfriend used to give me grief for not wearing a helmet. I invited her to read around the subject (and did not provide her with any links at all), she's stopped bothering me about it now...

I just don't get this. you use anecdote to justify not wearing one, stating "I'm not sure there is any circumstances where...." but throw out as invalid anecdotal evidence demonstrating that indeed, it is possible to bang your head when cycling.

I fell off once, slid along a grass verge and smashed the TOP of me head against a tree. I knocked myself out. I have worn a helmet ever since.

I also came off as a kid and knocked myself out with a blow to the temple. Okay, the bike I was riding was about a 48cm frame and had 3 gears, but I'm pretty sure it qualified as a road bike and was being ridden on the road.

Sorry those are only anecdotes.

I know they are anecdotes. I'm not suggesting otherwise! The fact is that I balance the chances of coming off in a situation where a helmet would help versus my preference for riding without a helmet - and my preference wins out especially in light of my own experiences of coming crashes. I seriously have hit my head far more often off the bike than I ever have on it.

always_tyred

DonDaddyD wrote:

I just don't get it.

Please someone with a brain larger than mine explain.

There are instances when wearing a helmet is going to be more beneficial than not wearing a helmet.

Are there any or as many instances when not wearing a helmet is more beneficial than wearing one.

If not, then why choose not to wear a helmet when wearing one most certainly increases your safety in some instances.

Because they are uncomfortable and sweaty.

always_tyred

jashburnham wrote:

I know they are anecdotes. I'm not suggesting otherwise! The fact is that I balance the chances of coming off in a situation where a helmet would help versus my preference for riding without a helmet - and my preference wins out especially in light of my own experiences of coming crashes. I seriously have hit my head far more often off the bike than I ever have on it.

Which is absolutely fair enough.

But not the same as saying tha they don't do any good. Its a personal risk assessment excersise and for an experienced and alert cyclist, its a valid choice.

velorazzi

Right, I've been following this debate with interest and I'm getting a little upset that we're all getting angry with one another - like two kittens whose play fight has become suddenly more serious, and now were glowering at one another with ears back and tails flicking.

I'd like to ask a related question: Does anyone know the truth about age (of the helmet, before you start) affecting the effectiveness of cycle helmets? I have two; one between 12 to 14 years old, relatively cheap, British made (yes it did happen in days of yore) and the other a couple of years old, fairly pricey, which I bought as the other had next to no ventilation and was, well, old.

I don't really wear the old one any more but it appears perfectly sound and would probably do if I bent the other. So, should I keep it or ditch it - and when should I replace the newer one?

Thank you

Now, on another matter. I think that now is the time in the debate for a group hug...No? Aww, come on. You know you want to, yes you do. Yes you d...

...Oh, I'll get me coat... :oops:

GyatsoLa

I've been following this discussion with a certain amount of interest, not to mention despair. It seems people are incapable of stepping back and looking clearly at the evidence. For those who claim a scientific background, thats pretty discouraging. This is pretty well reflected in this (somewhat out of date) DoT summary of the arguments:

http://www.dft.gov.uk/pgr/roadsafety/re ... 26?page=11

Unfortunately, a lot of the papers are not accessible on the web, but there is an interestng, if inconclusive debate about risk compensation here:

http://www.mayerhillman.com/Articles/En ... aring.aspx

This is a little out of date, there has been a lot more evidence published since the debate, most notably Ian Walkers by now famous/notorious research.

I do find it interesting that a lot of the comments here along the lines of 'I wear a helmet because it makes me feel safer', actually supports Hillmans contentions (if you read it through you'll see why).

If we assume the argument is solely about an individuals choice to wear a helmet (as opposed to confusing it with the debate about compulsory helmet use), then really everything rests around an interpretation of risk compensation theory and how it applies to cycling (not just to cyclists, but to drivers passing cyclists). Any reasonable overview would conclude that there isn't any conclusive evidence on this either way. Some of the discussion here has (in my opinion) been downright wilful in the way some posters refuse to come to grips with the concept, which makes any discussion pointless.

wgwarburton

Hi,

Citing Malcolm Wardlaw:
....A British
cyclist who rides for 280 hours per year (2,300 miles) will face
an annual risk of death about double that of a British driver,
but the risk is low at 0.0083% per year. This risk corresponds
to an expectation of travelling 280 hours’ per year for 12,000
years – the same as for a German driver and safer than a Belgian
driver.

Does that help? It doesn't cover "SI"s, of course, only "K"s but gives some idea of the level of risk we're exposed to.

We can bat anecdotes and artificial experiments around 'till we're blue in the face. It isn't going to prove anything. As I said before, one of the things I find most compelling is that people are trying very, very hard to prove reliably that helmets are worthwhile (governments, helmet makers, safety bodies etc.) and failing to come up with anything compelling. That, in itself, is deeply suspicious.

I believe, from the studies I've read and the evidence I've seen that helmets are unnecessary and ineffective. I may be wrong, and will continue to keep an eye on developments in order to re-evaluate the situation.

What grates is that people who don't appear to have done much investigation into the matter want to tell others what to do on the basis of common sense and anecdote, when there is some credible evidence that the common sense judgement is unfounded and that the anecdotes are largely meaningless....

Cheers,
W.