CTT introduce compulsory helmets and front lights

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Steady rider
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Re: CTT introduce compulsory helmets and front lights

Post by Steady rider »

Actually there is a point as it provides sufficient data, plus adding cycling data on billion miles per year for each year, so that both admissions and head injuries per billion miles cycled can be calculated. It shows admissions increased, possibly supporting risk compensation, and it suggests some benefit in a lower proportion of head injuries. Younger children had a greater take up of helmets than teenagers but had less of a percentage reduction. Adults had the higher percentage reduction in head injuries but road safety improved, so that some of their reduction could be due to lower driving speeds perhaps.

I think we could speculate on risk compensation issues for years and perhaps looking at particular data may be more useful.

Overestimation of the effectiveness of the bicycle helmet by the use of
odds ratios. by Th. Zeegers , International Cycling Safety Conference 2015
15-16 September 2015, Hanover, Germany https://cyclist.ie/wp-content/uploads/2 ... elmets.pdf
It must be concluded that any case-control study in which the control is formed by hospitalized
bicyclists is unreliable and likely to overestimate the effectiveness of the bicycle helmet.
So the systematic review methods based mainly on hospital based reports can be considered unreliable.
drossall
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Re: CTT introduce compulsory helmets and front lights

Post by drossall »

Jdsk wrote: 18 Jan 2022, 6:23pm
drossall wrote: 18 Jan 2022, 6:05pmBut any idea that risk compensation completely negates the benefits of any safety measure is ridiculous.
I wouldn't use that word. But I would describe the belief that it inevitably happens in all circumstances or inevitably negates all of the benefits as dogma.

We'll find out when and where and how much it happens by studying it. As is happening already.
I'm not an expert, but it seems to me that it's a human behavioural thing, and it would be hard to see how it could happen in some circumstances and not in others. So, assuming that it happens at all, it would be more a case of it not being a significant effect in some circumstances.

It seems inherently reasonable if you think about it backwards. Imagine that I line up two bikes - your usual one, and one with brakes that feel really spongy. Assuming that you're prepared to ride with them at all, do you take more care with the spongy brakes than with your normal ones? And, after riding with those, do you take only normal care when you go back to your normal bike? Isn't that risk compensation in action? If I then gave you a third bike with even better brakes (and tyres), wouldn't it be logical to push things even a bit more down that brilliant descent?
Stevek76
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Re: CTT introduce compulsory helmets and front lights

Post by Stevek76 »

I think perceptions and perceived risk are better words than 'beliefs'. And yes, it is of course perceptions that drive behavioural choices, including where risk is part of that choice. Hence why getting mode shift to cycling is far more about providing an environment in which riders feel safe (also pleasant) rather than actually that much safer (GB fatality rate is less than 3 times higher than NL) and why training/vehicularism will never work. You can tell people that cycling is actually really quite safe until you're blue in the face, dry stats about casualty rates doesn't do much to change perceptions formed on a busy road.
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mattheus
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Re: CTT introduce compulsory helmets and front lights

Post by mattheus »

Stevek76 wrote: 19 Jan 2022, 12:17am I think perceptions and perceived risk are better words than 'beliefs'.
Can you provide evidence of that?

Thanks

/jdsk
drossall
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Re: CTT introduce compulsory helmets and front lights

Post by drossall »

They were my words, I think. I didn't mean to make that fine a distinction. You can call it what you like - it's the idea that mattered :D :D
thirdcrank
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Re: CTT introduce compulsory helmets and front lights

Post by thirdcrank »

I thought the RTTC "as was" was fundamentally opposed to fairings etc., and I also thought that helmets designed for time trialling tended to be bonce-fairings rather than protection.
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pjclinch
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Re: CTT introduce compulsory helmets and front lights

Post by pjclinch »

Studying risk compensation...

It's psychology, which while a science using scientific method has (at least so ISTM, as a non-psychologist) a huge pile of extra confounders over everything compared to physics and engineering disciplines. My BSc is in geophysics, and even there with completely deterministic processes we understand well there were sufficient unknowns to joke about how it was made up as we went along (joke my tutor told, engineer, mathematician and a geophysicist at a job interview which comes down to a final question, "what is 2+2?", engineer says 3.99 +/- 0.1, mathematician says exactly 4, geophysicist answers, "what would you like it to be?"). I learned from that that there are pretty big holes around what we can be sure of, and psychology is, I suspect, particularly prone to this, and also prone to being hilariously misunderstood and the problems underestimated by people outside the field, particularly those with a bee in their bonnet like Jake Olivier..
Would I trust a systematic review of risk compensation? That would depend on what was being reviewed, how good that work was (we all know just being published doesn't make something good), and who was doing it. I wouldn't trust it blindly just because it was a systematic review, and I wouldn't think it necessarily better than the work laid out in Risk which is fairly hedging of its bets in any case.

One thing I'm reasonably confident about is that different people respond very differently to risk, and that what one is looking for in policy is a very broad common denominator, i.e. this intervention will do significantly more good than harm. This makes psychological effects potentially very difficult to factor in to policy decisions beyond understanding that they will make the error bars bigger. But as anyone who's done physics knows, you do have to account for the size of the error bars when stating something with confidence. It's still science if we say "we don't know enough in here, and here are the wildly varying results we got that show we don't know enough, but there are effects in there we haven't learned to measure usefully yet".
I don't see raking over the coals of flawed reviews just because they happen to be available to be a good way to find those answers.

We can easily see risk compensation by looking around us. But predicting exactly what effect will be observed in a random individual, or population of random individuals, by an intervention like a lightweight crash helmet appears to me as a non-psychologist to be "non-trivial". There are just so many variables, even simple physical ones, with multiple layers of interacting psychologica//cultural/behavioural ones on top.

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Steady rider
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Re: CTT introduce compulsory helmets and front lights

Post by Steady rider »

Freestyle BMX may be one event that has added risks and without helmet use may not have been considered suitable for the Olympics.
mattheus
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Re: CTT introduce compulsory helmets and front lights

Post by mattheus »

Steady rider wrote: 20 Jan 2022, 10:04am Freestyle BMX may be one event that has added risks and without helmet use may not have been considered suitable for the Olympics.
The Olympics? Hmm, I wonder how they approach helmets ...

https://www.nytimes.com/2016/08/07/spor ... uards.html

"
...
Several studies, including one commissioned by the association, found that the number of acute brain injuries declined when head guards were not used. In the world championship tournaments overseen by the association from 2009 to 2013, the number of times a fight was stopped because of one boxer receiving repeated head blows fell 43 percent in bouts without head guards compared with fights with head guards.
...
"
thirdcrank
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Re: CTT introduce compulsory helmets and front lights

Post by thirdcrank »

Now that the thread has move on from the CTT rules, I feel ok about posting this here

SnowDome death: Helmet rule change would be 'legacy'

... Sutton Coldfield MP, Conservative Andrew Mitchell, (of Plebgate fame) has written to Culture Secretary Nadine Dorries to ask her to look at the issue.

Mr Mitchell also raised the issue in the House of Commons in December adding: "There is little doubt that a helmet would have saved Louis's life.

"His death was not only tragic but wholly avoidable." ...
https://www.bbc.co.uk/news/uk-england-s ... e-60068140
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pjclinch
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Re: CTT introduce compulsory helmets and front lights

Post by pjclinch »

Steady rider wrote: 20 Jan 2022, 10:04am Freestyle BMX may be one event that has added risks and without helmet use may not have been considered suitable for the Olympics.
Organised sport tends to be quite a long way up its own backside where "uniforms" are concerned, so we have beach volleyball where the men running the sport find it necessary to have the women playing in much less than the men, and in skiing the older racing is in skinsuits but the snowboarders apparently have to war baggy stuff (even though it'll slow them down...), you can only play snooker in a waistcoat and bow tie, football is impossible in leggings unless you're a goalie, and so on.
In other words, I would not be at all surprised if culture (of the competitors and the organising bodies) around the sport weren't playing at least as much part as any analysis of injury data in deciding what gets used.

Not that I wouldn't want a bit of extra protection of myself trying that sort of thing, if my fear-glands regressed to teenage levels of development. But I note that quite a few kids doing bonkers stuff seem happy without. More culture and psychology, I think.

Pete.
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Stevek76
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Re: CTT introduce compulsory helmets and front lights

Post by Stevek76 »

I've discussed some of the evidence in that Esmaeilikia/Oliver review most of the times it's been linked here (albeit indirectly in this particular case).

Most of the constituent studies it looks at aren't asking the right question as they're case control studies. Thus they answer questions about differences in behaviours between cyclists that choose to use helmets and those that do not. This entirely misses the point as risk compensation is about potential change in behaviour of the same cyclist(s) with and without helmets. Trying to establish this from case control studies shows a fundamental failure to understand risk perception and psychology.

The choice to wear a helmet or not is going to be strongly linked to a person's perception and attitude to risk so it's not even a situation where you can attempt to control for confounding variables with careful sampling or weighting, the very thing you're attempting to measure is guaranteed to differ between the two groups. And that's before we even look at the various rather arbitrary measures of 'risky behaviour' that most of these studies use.

The one study it looks at that does actually take groups of cyclists and assess their riding both with and without helmets, the review incorrectly classifies as showing risk compensation in the wrong direction.

Unfortunately I think a big issue here is that the kind of situation that would actually show the difference would probably fail any ethics approval. So embedded is the notion that helmets are a requirement means that actually asking volunteers to cycle without them in anything other than highly controlled and trivial situations isn't going get through.

A study that actually got a grasp on cycle helmet related risk compensation would need to be doing something like sending volunteers out with and without helmets on busy roads (which would be more reflective of transport cycling but with less control over random variation), or chucking them down a nice techy red run at bike park wales and seeing how fast they do it (less transport but very low random variation)
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pjclinch
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Re: CTT introduce compulsory helmets and front lights

Post by pjclinch »

Stevek76 wrote: 20 Jan 2022, 12:42pm <snip stuff I basically agree with>
A study that actually got a grasp on cycle helmet related risk compensation would need to be doing something like sending volunteers out with and without helmets on busy roads (which would be more reflective of transport cycling but with less control over random variation), or chucking them down a nice techy red run at bike park wales and seeing how fast they do it (less transport but very low random variation)
And even that brings you awkward confounders. Steady Rider has suggested various experiments to show that e.g. helmets affect balance by attaching all sorts of accelerometers to a rider and having them complete an obstacle course with and without a lid, but I shot the experiment design down in flames because it needs to be the same rider on the same course with lots of runs to give a working average but there can't be any learning between the runs, and the more technical it is I guess the more practice will affect it. And so on.

Science gives us tools but they're not always particularly well suited to all experiments. Case/control on bike crash accident victims to understand risk compensation is not a good match of tools to problem. Add in reviewers that don't seem to understand that and however systematic they are gets to be a bit of a moot point.

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Steady rider
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Re: CTT introduce compulsory helmets and front lights

Post by Steady rider »

Just adding a simple suggestion, layout two designs so a cyclist can ride between two lines, probably forming a circuit, use equipment to measure stability aspects, compare results per cyclist, with and without helmet. Having an index per individual, to measure how their balance is before cycling could be a starting point.
Some research from Scotland is available
https://ietresearch.onlinelibrary.wiley ... .2018.5181
Last edited by Steady rider on 20 Jan 2022, 1:50pm, edited 1 time in total.
Jdsk
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Re: CTT introduce compulsory helmets and front lights

Post by Jdsk »

interventional trials would help enormously, and it's an interesting point about Research Ethics Committees.

From the discussion above there would be much bigger problems than any pre-existing opinions of the Committee. Trials using placebo surgery have been approved, and at least one of not wearing masks in surgery has been performed. Not wearing a helmet shouldn't be impossible.

An application would be much more likely to succeed if it didn't rely on ad hominem criticisms and didn't suggest that a 20y old monograph based on a 30y old report outweighs all subsequent studies. And if it addressed specific questions. And any Committee would be looking for a systematic approach in the literature review.

And it's going to be difficult to run a study of adequate power because the rate of injury is so low.

Jonathan
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