Stop Headway - Campaign

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.
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anothereye
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Re: Stop Headway - Campaign

Postby anothereye » 24 Sep 2010, 5:25pm

snibgo wrote:Personally, I don't care if I pick up a few scrapes and bruises, but I do care greatly about getting a brain injury with effects of more than a day or so.

My position is:

- If I'm in an accident, a bike helmet may mitigate such an injury. Or it may exacerbate it.
- It may increase the chance of me being in such an accident.
- It is almost totally irrelevant to my safety while cycling. Factors under my control that are far more important include: bike roadworthiness, my cyclecraft, and my choice of when, where and how to ride.

I do sometimes wear a bike helmet. It is Snell-certified.

I never wear one while walking or in a car. Why not? My position here is difficult to defend. After all, my chances of brain damage as a car occupant or pedestrian are similar to that as a cyclist.
+1. well put snibgo, you just saved me the trouble of writing more. I'd only add; safety in numbers: wearing a helmet seems to discourage others from cycling.
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snibgo
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Re: Stop Headway - Campaign

Postby snibgo » 24 Sep 2010, 7:00pm

I agree that helmet-wearing and promotion encourages the mistaken view that cycling is significantly more dangerous than walking or being in a car, hence tends to reduce cycling numbers, hence increases the danger to remaining cyclists.

However, that doesn't affect my personal choice. If I believed a helmet was significantly safe (or unsafe) for me, I would always wear one (or never wear one).

mattheus
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Re: Stop Headway - Campaign

Postby mattheus » 24 Sep 2010, 7:41pm

Jonty wrote:... "scrapes and grazes".
You make these sound trivial but that depends on their severity.
What about lacerations and perhaps bruising? Would helmets not reduce these?
Are these not head injuries?
jonty

You're more likely to get lacerations and bruising on your knees, elbows, hands (and possibly shoulders and hips, but we cover those most of the time already) - just google for some pictures.
None of the above are life-threatening. I might worry about a bruised/cut cheek if I were a model, but at the moment they are a very low priority.

If you're worried about them, wear a helmet - (almost) noone is stopping you :) (But please also consider knee-pads, elbow pads, gloves, face-guard ... )

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Re: Stop Headway - Campaign

Postby SilverBadge » 24 Sep 2010, 10:08pm

MartinC wrote:Lacerations, bruising, etc. This is getting to the nub of one of the issues. What's a reasonable expectation from an effective helmet? Knowing that a helmet might mitigate some trivial injuries and then implicitly inferring that it might do much more beyond that is a leap of faith.

The reasonable expectation is that an EN1078 "cycle" helmet will prevent serious cranial injury in the sort of simple "fall from head height" no other vehicle involved accident that 95ish per cent of cyclists fatalities aren't.
DfT seem to have retreated a bit in their positioning (not surprising since the most recent research is considerably less favourable) - to me it now tries to not actually fib in a "probably better than not wearing one" message (also translatable as "wear one as DfT/Governement is too spineless to do anything else to combat cyclist injuries") - still sailing rather close to the wind with statements about fatality numbers closely following by phrases such as "cycle helmets would be expected to be effective in a wide range of . . . . the most common accidents" when fatalities is what they don't do well. It's a bit like saying you can still win the vast majority of national Lottery prizes if you only have three numbers on your ticket, omitting to mention that it's only a tenner you could win, not the multi-million jackpot.

I guess I might get classified as anti-helmet, but I don't think I am. What I am opposed to is the hypeing of helmets, for cyclists and no-one but cyclists, mainly by people who don't cycle and would rather not address their motoring complacency/negligence. If people choose to wear helmets as a personal choice on rational evaluation of the evidence of risk and mitigation, not only for cycling but for all other equally risky activities, and this doesn't dilute the other measures that could and should be taken for cyclist safety, that's just fine by me.

The BMA's position is interesting and I'm sure you'd be interested to google around and find out more about this. The BMA's position was fairly agnostic for a long time based on their Cycling and Health study from the mid nineties (google Mayer Hillman). They reversed this recently at a conference where a motion was pushed through with virtually no debate leaving many members unhappy with the outcome.

IIRC the numbers are swinging increasingly anti-compulsion, now at a majority but not big enough to reverse the policy yet?

Jonty

Re: Stop Headway - Campaign

Postby Jonty » 25 Sep 2010, 4:05pm

I see that James Cracknell believes that his helmet saved his life. He says "When the truck's wing mirror hit me on the back of the head some of the impact was absorbed my my helmet. Has it not been, this article would have been submitted by a ""ghost"" writer".
A bit better than a scrape and a scratch I suggest.
But perhaps like doctors he too is misguided and easily mislead.
jonty

snibgo
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Re: Stop Headway - Campaign

Postby snibgo » 25 Sep 2010, 4:11pm

As is often pointed out: unless he repeats the experiment, we'll never know.

I have no problem believing the helmet mitigated the impact, and hence the injury. If he believes it saved his life, well, so be it.

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Si
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Re: Stop Headway - Campaign

Postby Si » 25 Sep 2010, 4:15pm

snibgo wrote:As is often pointed out: unless he repeats the experiment, we'll never know.

I have no problem believing the helmet mitigated the impact, and hence the injury. If he believes it saved his life, well, so be it.


I'm afraid that you are wrong. James Cracknell is a media personality / celebraty. Anything that celebs say must be true, for they are our gods and we must obey. :wink:

Jonty

Re: Stop Headway - Campaign

Postby Jonty » 25 Sep 2010, 4:30pm

snibgo wrote:As is often pointed out: unless he repeats the experiment, we'll never know.

I have no problem believing the helmet mitigated the impact, and hence the injury. If he believes it saved his life, well, so be it.


You could always repeat it but without wearing a helmet. I'm sure the truck and it's driver could be hired for the restaging. Then you could have your definitive proof, or rather we could have it.
Are you up for it? :wink:
jonty

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bovlomov
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Re: Stop Headway - Campaign

Postby bovlomov » 25 Sep 2010, 5:04pm

Surely that is an experiment that can be done in a laboratory.

The deceleration of the skull and of the brain, with an inch of polystyrene and again without. Or at least done with materials of similar mass.

It seems the most serious injury was the brain damage at the front rather than the fracture at the back. Is this like putting a dried pea in a cocoa tin and whacking it for six with a cricket bat? A bit of polystyrene might stop the tin from being dented, but it doesn't stop the pea from rattling around. Sorry if that's too technical!

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Re: Stop Headway - Campaign

Postby snibgo » 25 Sep 2010, 5:49pm

A lab experiment could find the deceleration, but wouldn't resolve the dead or alive question.

A brain is closer to a bowl of cold porridge than a pea.

When a head is bashed ("suffers a rapid deceleration") from one side, the brain compresses towards that side, and then it bounces back to the opposite side, and that bounce-back is where the damage commonly occurs. They call it "contre coup" or something.

Whack a person on the back of his head (like James), and the front is damaged. Whack a person on the right (like me), and the left gets damaged.

Jonty

Re: Stop Headway - Campaign

Postby Jonty » 25 Sep 2010, 6:16pm

[quote="snibgo"]A lab experiment could find the deceleration, but wouldn't resolve the dead or alive question.

A brain is closer to a bowl of cold porridge than a pea.

Surely if the "experience" is simulated in a lab and the comparative masses, velocities etc are realistically reproduced, thereby obviating the need for a restaging of the event, and it results in the dried pea/cold bowl of porridge/cocoa tin being virtually "decapitated", one could reasonably conclude that the dead or alive question would be resolved in favour of the former.
Do you not think this is a reasonable hypothesis or are you still inclined towards the need for definitive proof by restaging the event?
jonty :wink:

Jonty

Re: Stop Headway - Campaign

Postby Jonty » 25 Sep 2010, 6:24pm

Si wrote:
snibgo wrote:As is often pointed out: unless he repeats the experiment, we'll never know.

I'm afraid that you are wrong. James Cracknell is a media personality / celebraty. Anything that celebs say must be true, for they are our gods and we must obey. :wink:


Si, are you not a media celebrity as well?
Jonty :wink:

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Re: Stop Headway - Campaign

Postby snibgo » 25 Sep 2010, 6:35pm

Jonty wrote:Surely if the "experience" is simulated in a lab and the comparative masses, velocities etc are realistically reproduced, thereby obviating the need for a restaging of the event, and it results in the dried pea/cold bowl of porridge/cocoa tin being virtually "decapitated", one could reasonably conclude that the dead or alive question would be resolved in favour of the former.


What deceleration (and over what time) causes decapitation, or less spectacular death, or irreversible brain damage, or a mild headache? I don't know. Why does the Snell standard specify 300g rather than 200g or 400g? I don't know.

Perhaps the various standards that specify maximum allowed deceleration are based on some research. Or perhaps they are wild guesses.

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7_lives_left
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Re: Stop Headway - Campaign

Postby 7_lives_left » 26 Sep 2010, 12:04am

snibgo wrote:What deceleration (and over what time) causes decapitation, or less spectacular death, or irreversible brain damage, or a mild headache? I don't know. Why does the Snell standard specify 300g rather than 200g or 400g? I don't know.

Perhaps the various standards that specify maximum allowed deceleration are based on some research. Or perhaps they are wild guesses.

No they are not wild guesses. Don't know how to put this delicately, but at some point someone will have carried out a test on a cadaver. The results of that test will have been used as a benchmark so that when they do subsequent tests, they don't have to use a cadaver each time. Much more pleasant for the testers that way.

Wikipedia:Crash test dummy-Cadaver testing

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bovlomov
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Re: Stop Headway - Campaign

Postby bovlomov » 26 Sep 2010, 10:56pm

7_lives_left wrote: Don't know how to put this delicately, but at some point someone will have carried out a test on a cadaver.


Erk! Couldn't they just do it with a dried pea in a cocoa tin? Or cold porridge in a ming vase?