A few notes on helmet standards and injuries:
Firstly a bit of history - The Snell Memorial Foundation was started because
of the death of a driver in a SCCA sports car race.
Bell Helmet Company was founded and they discovered that the motorcycle
crowd was a more lucritive audience for the products. Around 1988 or so,
Bell had a legal opinion written that essentially said that helmets had no
effect on motorcycle deaths and injuries and so if they continued to market
to motorcyclist who were mostly young foolish individuals that Bell could
expect to be sued out of business for contributing to reckless driving of
motorcyclists.
Bell twigged that a helmet would be just as easily marketed to bicyclists, a
sport that was starting to grow again after years of hibernation. Since
serious bicyclists tend to be older individuals they would be a great deal
less likely to have outraged parents suing on their behalf. Moreover, since
serious and fatal injuries among bicyclists were some 400 times less common
per capita, the chance of someone blaming a helmet for increasing the
reckless behavior of the wearer would be rather small.
Bell used the standards set by the Snell Memorial Foundation. Let's say
this - although Bell and Snell BOTH know that bicycle helmets have a faulty
standard and are incapable of dealing with anything beyond a very minor blow
to the helmet, they both do an excellent job at what they do - Snell has
designed the very highest standard that is possible to obtain and Bell has
designed the very highest quality helmets to test to and maintain that
standard.
The problem is that the standard is totally inadequate.
For instance - effectively the test for impact is for a fallover. That is,
dropping your head some 6 feet and striking the ground. If you fall over at
a stop you acheive the maximum impact that a helmet could possibly be
designed for.
And the definitions for maximum impact that the standard sets is for a large
strong man whose skull can (just) withstand a 300 gee decelerative force
without breaking. Women and children as well as a significant proportion of
men, cannot withstand such a force without fatal decelerative skull damage.
Significantly - even this standard would leave a large strong man in a coma.
What's more - this is a full on straight contact. In real life the odd shape
of a "racing" helmet causes the head to twist on impact causing rotational
forces. The brain is injured fatally by rotational forces a small percentage
of those the helmet is tested to withstand.
Joe Moron wears a helmet, falls over, sticks out his hand and using his
muscles reduces the impact of his FACE to the ground to the point where he
recieves a bloody nose, scraps on his chin and a cut on his forehead from
the impact of the edge of the foam to his head. He then describes to
everyone how his life was saved by his helmet.
What he doesn't know is that Bell, in an effort to make helmets acceptable
to athletes have put so many vents in them that the foam had to be
significantly hardened. Interestingly, since the headform for the Snell
testing is metal, increasing the strength of the foam had no effect on the
acceptability of the helmet for the testing purposes. It still passes the
Snell standards.
However, because the foam now covers a much smaller area of the skull, local
pressures on a real skull can greatly exceed the forces necessary to break a
skull even within the range of the testing standards.
Not that it really matters of course since bicycle accidents of the sort
that would kill someone from an unassisted fall are almost nonexistant.
In fact - some 90+% of all serious and fatal accidents to bicyclists in the
USA involved collisions with motor vehicles with forces hundreds of times
larger than any helmet could possibly mitigate. Of the remaining 10% or
less - some 60 deaths a year across the USA - many of them are so obviously
asked for (downhillers hitting 100 mph through rocks) that no one has had
the temerity to try a lawsuit.
Moreover, although there is no research to back it up, there is a high
probability that helmets probably do reduce the severity of minor injuries.
Minor injuries are those that do not require at least an overnight stay in
the hospital. And since these sorts of injuries are fairly common it is
probably in society's interest to retain helmets manufacturers in the USA
and to promote the use of these helmets as somewhat effective.
The point of all this is that while helmets probably do some good, promoting
them as saving lives or as some sort of cureall for childrens injuries is
actively working against cycling.
"Simon Brooke" <[email hidden]> wrote in message
news:[email hidden]...
Quoted message said:in message <[email hidden]>, bar
(') said:Note that the two old farts ... er ... seasoned pros on the team (ie,
moninger and sayers) are the only tools not wearing helmets!! Surely
they can set a better example for the young guns than that.
Oh, for heaven's sake don't be silly.
Cycling is less than two thirds as dangerous as walking, and no-one wears
a
helmet when walking. On average a cyclist has one fatal accident for every
twenty one and a half million miles, or eight hundred and sixty three
complete circumnavigations of the earth. Cycling helmets are rated to
provide protection in falls up to 24Km/h. Fabio Casartelli was descending
at 100Km/h when he crashed and was killed. The force of impact scales with
the square of the speed, so Casartelli's fall exceeded the protective
specification of a bicycle helmet by a factor of sixteen times. Also - as
is typical in such cases - Casartelli's fatal injuries were not to the top
of his head, but to the side and front.
Quick summary: you'll never need it, and if you did ever need it it
wouldn't work.
Addendum: when I crashed while descending at 75Km/h, I was wearing a
cotton
cap. Now, OK, if I'd hit my head in that crash I would not be writing
this. But I didn't (I had a slight graze on the temple, some lacerations
to my legs, and a broken back, but...) What happens in a high speed crash
is a matter of luck, but getting killed isn't inevitable and it isn't even
very likely.
--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
;; Drivers in the UK kill more people every single year than
;; Al Qaeda have ever killed worldwide in any single year.
