"Denialism" and cycle helmets

[Vorpal]

I have never understood the principle where people see utility cycling as "safe" enough not to need. a helmet, yet faster rides a helmet becomes necessary.

To my logical way of thinking that is absurd

We have a helmet that is tested and certified for impacts at speeds up to about 12 mph...... so lets only wear it for activities outside the performance parameters!

If you wish to wear a helmet to "prevent" head injuries, then the logical thing is to operate within its proven design and not cycle above 12 mph when wearing one.

Otherwise it is a bit like having brakes designed to stop at 20 mph, and then expecting them to function at higher speeds as well

I don't think that is a very good analogy.

If we accept for the sake of argument that helmets have some capability to absorb energy, and reduce an injury, then they will absorb energy, up to their maximum capability whether the impact speed is 12 mph or 20 mph. It's just that a a 20 mph impact is more likely to exceed the energy absorption capability. That doesn't make it pointless to wear.

It also ignores that people might have other reasons to wear a helmet. The principle reason in my case is that I sometimes enter events that require them. If I want to do an event, I typically protest (once) helmet rules, just to make my point, then take my helmet along, and ride the event anyway. Why? Because I want to participate, and my not doing so out of protest will not be noticed by anyone, or contribute to any cultural changes.

[[XAP]Bob]

it occurs to me that if everyone just wore them (even in a small, representative locality), then their efficacy would soon be proven (or not). Either way the distraction would be over, and we could perhaps concentrate on more important matters.

Compare those with other road safety initiatives:

[[XAP]Bob]

I have never understood the principle where people see utility cycling as "safe" enough not to need. a helmet, yet faster rides a helmet becomes necessary.

To my logical way of thinking that is absurd

We have a helmet that is tested and certified for impacts at speeds up to about 12 mph...... so lets only wear it for activities outside the performance parameters!

If you wish to wear a helmet to "prevent" head injuries, then the logical thing is to operate within its proven design and not cycle above 12 mph when wearing one.

Otherwise it is a bit like having brakes designed to stop at 20 mph, and then expecting them to function at higher speeds as well

I don't think that is a very good analogy.

If we accept for the sake of argument that helmets have some capability to absorb energy, and reduce an injury, then they will absorb energy, up to their maximum capability whether the impact speed is 12 mph or 20 mph. It's just that a a 20 mph impact is more likely to exceed the energy absorption capability. That doesn't make it pointless to wear.

Depends on the absorption mechanism...

If the energy is absorbed by plastic deformation of the helmet (i.e. crushing the polystyrene) and high speed collision results in a brittle fracture, but not plastic deformation, then the amount of energy that is absorbed could be negligible.

So it genuinely could be pointless at speeds outside the design parameters. Particularly given that the energy is proportional to speed squared (so gets large pretty quickly) and that the devices are designed down to a weight and strength that is targeted for a low energy impact.

[pjclinch]

[
Depends on the absorption mechanism...

If the energy is absorbed by plastic deformation of the helmet (i.e. crushing the polystyrene) and high speed collision results in a brittle fracture, but not plastic deformation, then the amount of energy that is absorbed could be negligible.

So it genuinely could be pointless at speeds outside the design parameters. Particularly given that the energy is proportional to speed squared (so gets large pretty quickly) and that the devices are designed down to a weight and strength that is targeted for a low energy impact.

But as noted already, the real game is the rate at which KE is lost, not your headline speed on impact. As motorcycle racers sometimes demonstrate you can come off and slide at 100 mph and not do much damage thanks to nothing stronger than a decent set of racing leathers, because you're scrubbing off the KE relatively slowly. It's if you slow to a stop pretty much instantaneously that things break, and the thing that typically stops you dead is the ground, but only in the vertical plane.

In the vertical plane you're only likely to get much above 12 mph if Big Air or riding off drops are involved, because you just don't have far enough to accelerate to much more as you fall. So being pointless hitting the ground vertically at terminal velocity having jumped off a cliff head-first is a very different matter to travelling at the same speed horizontally but only dropping from head height. If you hit a wall, or perhaps an oncoming car, at the same speed horizontally that could well be curtains, of course, but again that's not the same as "useless at 40 mph"

Pete.

[Vorpal]

Depends on the absorption mechanism...

If the energy is absorbed by plastic deformation of the helmet (i.e. crushing the polystyrene) and high speed collision results in a brittle fracture, but not plastic deformation, then the amount of energy that is absorbed could be negligible.

So it genuinely could be pointless at speeds outside the design parameters. Particularly given that the energy is proportional to speed squared (so gets large pretty quickly) and that the devices are designed down to a weight and strength that is targeted for a low energy impact.

Well, that's fair enough, but not all helmet materials work that way, and even polystyrene is likely, in many circumstances, to absorb some energy before failing in a brittle mode.

There has been some independent testing of cycle helmets done.

And while some of them do not meet even the minimal requirements (I don't think too much of the alarmist writing style in the Copenhagenize article, but it discusses two helmets that don't meet basic standards), others have been demonstrated to absorb energy effectively under alternative (test) conditions, such as oblique impact, based on reducing risk of skull fracture (though not necessarily soft tissue damage), or higher energy (measured in g force) versus both linear shock and rotation damage, given various impacts.

Also, finite element analysis has been carried out under independent study
https://www.ncbi.nlm.nih.gov/pubmed/26974030
http://www.ircobi.org/wordpress/downloa ... 4/4_10.pdf
http://www.arpnjournals.org/jeas/resear ... 6_4448.pdf

In conclusion, although specific helmets may fail in brittle mode when the design (test) parameters are exceeded, this does not apply to helmets in general. I think that the absorption capabilities of helmets has been demonstrated for a variety of circumstances (including some crashes). I won't say that all of the studies are without problems, and some, in fact are open to considerable criticism, but for reasons other than the energy absorption of the helmets in the studies.

There are, of course many other factors, as we have discussed here many times, that affect the effectiveness (or not) of helmets.

[random37]

I've just got back to cycling after a long break. I can't believe this is still something we are arguing about.

I wear a helmet sometimes, but most of the time I don't. If I was riding an MTB and therfore more likely to come off I would. I respect the idea of a hairnet for road cycling, but think that in most road accidents, they are not capable of providing meaningful protection in the way they seem to be marketed. No one cares what I think about helmets, though.

The problem with cycling in the UK is the design of roads, the behaviour of some drivers, and as someone who's been looking at bikes a lot recently, most of the bikes non-cyclists are steered towards by the cycling industry. I don't think I should have to wear special clothes, or buy accessories that make my bike suitable for riding to work.

Squabbling over this issue does a great disservice to cycling.

[pjclinch]

Squabbling over this issue does a great disservice to cycling.

You're not wrong there. The thing is stopping the squabbling.

We have the situation where Chris Boardman presents a piece on prime time TV about something that will make a tangible difference to cyclist safety and public health, and when questioned the journo will ignore everything just said and bang on about helmets. For many people "cycle safety" and "helmets" are practically synonyms, and until that is dispelled great disservice will continue. If you can think of a way of dispelling it with no squabbling I'd be very interested to know!

Pete.

[The utility cyclist]

I've just got back to cycling after a long break. I can't believe this is still something we are arguing about.

I wear a helmet sometimes, but most of the time I don't. If I was riding an MTB and therfore more likely to come off I would. I respect the idea of a hairnet for road cycling, but think that in most road accidents, they are not capable of providing meaningful protection in the way they seem to be marketed. No one cares what I think about helmets, though.

The problem with cycling in the UK is the design of roads, the behaviour of some drivers, and as someone who's been looking at bikes a lot recently, most of the bikes non-cyclists are steered towards by the cycling industry. I don't think I should have to wear special clothes, or buy accessories that make my bike suitable for riding to work.

Squabbling over this issue does a great disservice to cycling.

Yes, shall we tell the denialists to simply shut up about wearing helmets and let people cycle helmet free without abuse, stop the denialists from ejecting people wishing to ride a bike helmet free from clubs due to helmet rules, tell the denialists to shut up about having to wear helmets at cycling events, tell the denialists to be quiet about forcing children to wear helmets for cycle training (or be excluded otherwise). The denialists include the police, government and others who bang the helmet drum.
There's only one group who are the problem on this matter and they are the ones that shout the loudest and force others to go by their rules or you are simply not welcome!
Until that time comes I and others will continue to 'squabble' or rather make salient points to the denialists that their forcing of others to their will is not welcome and is in fact dangerous, or would you rather 'they' win, because that's the way it's going if we don't face up to these bullies

[pjclinch]

Calling a huge cast of folk "denialists" probably won't help anyone. A lot of the people castigated there are simply working from pervasive cultural values, an entirely natural and normal thing to do. It needs to stop, but calling them names isn't the way to do it.

[Cunobelin]

Squabbling over this issue does a great disservice to cycling.

What does a disservice to cycling is the underhanded lies, misleading claims and emotive blackmail of the pro-helmet lobby

[The utility cyclist]

Calling a huge cast of folk "denialists" probably won't help anyone. A lot of the people castigated there are simply working from pervasive cultural values, an entirely natural and normal thing to do. It needs to stop, but calling them names isn't the way to do it.

The phrase was initially used toward non wearers up thread as I understood it, but the abuse one receives from the helmet lot (some of it frankly disgusting) is far in excess of being called a denialist.

[Cunobelin]

it occurs to me that if everyone just wore them (even in a small, representative locality), then their efficacy would soon be proven (or not). Either way the distraction would be over, and we could perhaps concentrate on more important matters.

Compare those with other road safety initiatives:

This is another confounding factor

It is unequivocal that when the helmet laws were introduced the number of head injuries increased when corrected for the decrease in cycling

However there were a range of other measures including breath testing, dangerous driving and checks on vehicle safety.

These produced large decreases in accidents and injuries. This SHOULD have presented a decrease in head injuries for cyclists regardless of helmets, what it does suggest is that the increase in head injuries post compulsion would be even greater if corrected for these factors as well

[Cunobelin]

I have never understood the principle where people see utility cycling as "safe" enough not to need. a helmet, yet faster rides a helmet becomes necessary.

To my logical way of thinking that is absurd

We have a helmet that is tested and certified for impacts at speeds up to about 12 mph...... so lets only wear it for activities outside the performance parameters!

If you wish to wear a helmet to "prevent" head injuries, then the logical thing is to operate within its proven design and not cycle above 12 mph when wearing one.

Otherwise it is a bit like having brakes designed to stop at 20 mph, and then expecting them to function at higher speeds as well

I don't think that is a very good analogy.

If we accept for the sake of argument that helmets have some capability to absorb energy, and reduce an injury, then they will absorb energy, up to their maximum capability whether the impact speed is 12 mph or 20 mph. It's just that a a 20 mph impact is more likely to exceed the energy absorption capability. That doesn't make it pointless to wear.

It also ignores that people might have other reasons to wear a helmet. The principle reason in my case is that I sometimes enter events that require them. If I want to do an event, I typically protest (once) helmet rules, just to make my point, then take my helmet along, and ride the event anyway. Why? Because I want to participate, and my not doing so out of protest will not be noticed by anyone, or contribute to any cultural changes.

It is because it is simple and factual.

If you were to use a set of brakes limited to 20 mph to stop from 60 mph then there would be a real danger and in reality an explanation that they may not function

If the brakes failed and you had an accident because you failed to stop, you would be seen as negligent or reckless in your actions.

Yet none of this simple visit to reality doesn't apply to helmets?

[pjclinch]

Calling a huge cast of folk "denialists" probably won't help anyone. A lot of the people castigated there are simply working from pervasive cultural values, an entirely natural and normal thing to do. It needs to stop, but calling them names isn't the way to do it.

The phrase was initially used toward non wearers up thread as I understood it, but the abuse one receives from the helmet lot (some of it frankly disgusting) is far in excess of being called a denialist.

Let's cut back to the point again: it needs to stop, but calling them names isn't the way to do it. That someone's called you worse doesn't make it helpful.

[pjclinch]

It is because it is simple and factual.

If you were to use a set of brakes limited to 20 mph to stop from 60 mph then there would be a real danger and in reality an explanation that they may not function

If the brakes failed and you had an accident because you failed to stop, you would be seen as negligent or reckless in your actions.

Yet none of this simple visit to reality doesn't apply to helmets?

I'm afraid Vorpal is right, it's an open-and-shut case for the Bad Analogy Police. Brakes are a basic control feature of a bike (even the fixie on a track bike), a helmet isn't, and control is fundamental. Beyond that, it's a bit like saying a parachute is pointless as a safety feature because you need to be at a certain height to use it, and planes don't always fly that high.

Pete.