Cooler Helmet?

[Mike Reed]

[email protected] wrote:
> Mike Reed wrote:
> > Michael Press wrote:
> > > ...they ride at 20+ miles / hour. ...
> >
> > That's a good point, but let's not forget that forward motion is only
> > one component of melon velocity in a bike crash. If you collapsed from
> > a standstill, you could still sustain a critical injury just from the
> > acceleration of gravity.
>
> In this context, "could" is pretty weak. Practically speaking, nobody
> ever does sustain a critical injury that way.

Neither of us have any data to refute or support my assertion. However,
practically speaking, what about a child falling off a nearly
stationary bike? How about an elderly person? How about somebody who
was riding slowly off-road, bumped their unhelmeted head off a tree
limb, and fell unconcious to the rocks he was riding over?

Just because it's rare doesn't mean it's not "practical."

> When toppling off a
> stationary bike, even if you somehow failed to break the fall with an
> outstretched arm, you'd absorb most of the energy with your elbow and
> shoulder.

That's where the injury comes in. Your elbow and shoulder compress
under the force of the fall, your neck bends, and your head accelerates
like the end of a whip into the ground.

> Practically speaking, you're as likely to suffer critical injury by
> tripping over a sidewalk crack when walking.

If you walk around holding a set of handlebars, I agree. You need a
little initial distraction for your hands to start things off. Your
feet are effectively taken out of the equation by your last step and
the crack, so it's pretty similar.

How about people falling from their feet on ice? That's more similar
because it's a less familiar recovery than trip-falling you've been
doing since you were 12 months old.

> > Moving forward fast will add additional significant impacts, but that
> > first one is pretty much just a function of falling over/sliding
> > out/going over the bars/etc.
>
> Although the risk of serious HI is always low when biking, I think it's
> significantly lower when not racing or training. The heat of
> competition (even just for fun) makes guys much more likely to touch
> wheels, or not notice the railroad track's flange slot, or run out of
> road on a fast turn, etc.
>
> Slow cycling is, by any rational standard, boringly safe - despite all
> the hype to the contrary.

Critical injuries in general are relatively unlikely for an individual,
so talking about how rarely some activity causes them is exercising the
obvious.

My whole point was not to forget the falling portion of a crash. The
forward portion is still important, but the fall itself is dangerous,
and that applies to anyone perched on one or two wheels, at any speed.

-Mike

 

[[email protected]]

Mike Reed wrote:
> [email protected] wrote:
> > Mike Reed wrote:
> > > Michael Press wrote:
> > > > ...they ride at 20+ miles / hour. ...
> > >
> > > That's a good point, but let's not forget that forward motion is only
> > > one component of melon velocity in a bike crash. If you collapsed from
> > > a standstill, you could still sustain a critical injury just from the
> > > acceleration of gravity.
> >
> > In this context, "could" is pretty weak. Practically speaking, nobody
> > ever does sustain a critical injury that way.
>
> Neither of us have any data to refute or support my assertion.

Given the intense interest the "safety" lobby applies to every source
of injury, if it were a problem, we'd _have_ data!

> However,
> practically speaking, what about a child falling off a nearly
> stationary bike?

Every child falls off bikes many times, and this has been true since
roughly 1890. Until bike helmet marketing began, it was correctly
judged to be as worrisome as a skinned knee caused by playing
hopscotch. It's _not_ serious.

> How about an elderly person? How about somebody who
> was riding slowly off-road, bumped their unhelmeted head off a tree
> limb, and fell unconcious to the rocks he was riding over?

If you've got a significant number of actual instances as examples,
please give them. Without such real examples, you're just wildly
hypothesizing.

For contrast, see
http://books.guardian.co.uk/review/story/0,,1753521,00.html?gusrc=rss

where they describe this 70-year-old's tough experiences in over 40
years of bicycle travel. Scary indeed - except for this part: "The
list extends back to her first and last attack of amoebic dysentery, in
Pakistan in 1963. But in all that time it does not include a single
cycling injury, despite the tens of thousands of miles she has pedalled
since setting off for India..."

We have an enthusiastic "safety" contingent who have tried hard since
at least 1990 to convince everyone that cycling is dangerous.
Obviously, they've done that. When people believe that a stationary
topple is likely to be really serious, people have been thoroughly
duped.

>
> My whole point was not to forget the falling portion of a crash. The
> forward portion is still important, but the fall itself is dangerous,
> and that applies to anyone perched on one or two wheels, at any speed.

<sigh> And perhaps anyone perched on two feet.

"You there! Either get that walking helmet on, or get crawling!"

- Frank Krygowski

 

[Werehatrack]

On Wed, 26 Apr 2006 09:09:07 -0300, "jtaylor"
<[email protected]> wrote:

>
>"Werehatrack" <[email protected]> wrote in message
>news:[email protected]...
>>
>> Besides, from a strictly actuarial standpoint, given the magnitude of
>> the risk *if* an event occurs, and the small cost of reducing it,
>> what's the payoff rate on average?
>
>The "payoff", as you put it, is (slightly) negative.

That's subjective. To me, the payoff's just positive enough to make
the helmet worthwhile, but then, I don't buy expensive lids or replace
them often...and the number of tree branches they've kept off my scalp
has been enough to make the personal payoff pretty good. Others can
do as they wish, what they do is no skin off my nose either way, but
I'll keep using the lid.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

 

[Mike Reed]

[email protected] wrote:
> > My whole point was not to forget the falling portion of a crash. The
> > forward portion is still important, but the fall itself is dangerous,
> > and that applies to anyone perched on one or two wheels, at any speed.
>
> <sigh> And perhaps anyone perched on two feet.
>
> "You there! Either get that walking helmet on, or get crawling!"

You obviously have a wonderful opportunity to save yourself $189.00 in
cycling gear by not wearing a helmet.

Enjoy!

-Mike

 

[jtaylor]

"Werehatrack" <[email protected]> wrote in message
news:[email protected]...
> On Wed, 26 Apr 2006 09:09:07 -0300, "jtaylor"
> <[email protected]> wrote:
>
> >
> >"Werehatrack" <[email protected]> wrote in message
> >news:[email protected]...
> >>
> >> Besides, from a strictly actuarial standpoint, given the magnitude of
> >> the risk *if* an event occurs, and the small cost of reducing it,
> >> what's the payoff rate on average?
> >
> >The "payoff", as you put it, is (slightly) negative.
>
> That's subjective.

No, actually, it's not.

The stats show that there is a slight increase in the risk of injury when
helmet laws, and consequent increased helmet wearing, are introduced.

There is also the probablility of the increase in population health costs
due to decreased cycling, noted by, among others, the BMA.

And as for the "magnitude of the risk" in cycling accidents, helmets do
little or nothing to protect, and possibly have a negative impact on, anyone
who is wearing one whist they are struck by an automobile (the most common
form of this most uncommon accident) in such a way as to cause serious
injury or death.

In sum:

Helmets don't work.

Cycling is not dangerous.

Helmets laws increase injury rates.

Helmet laws probably increase health costs.

 

[Sorni]

jtaylor wrote:
> "Sorni" <[email protected]> wrote in message
> news:[email protected]...
>
>>
>> I still maintain that MY chances of falling in a manner that would
>> cause me to hit my head on a hard and quite possibly sharp object
>> are much greater when I'm suspended 4+ feet off the ground on a
>> fast-moving thin-framed skinny-tired vehicle (controlled by...ME!)
>> than when I'm JWA or going down stairs or driving or whatever.
>> Therefore, I wear a helmet when engaging in the former activity and
>> don't when I'm not.
>>
>
> a) why do you think that you are different from the rest of the
> population?

I don't.

> b) do you also think, in light of a), that your (mis)perception sould
> be a reason for the rest of the population to adopt your solution?

Who said THAT?

 

[Mike Kaiser]

[email protected] wrote:

> Er, let's see . . .1,000,000,000/25.9 = 38,610,038.61 km/UK
> cyclist fatality, or 24 million miles.

Does anyone know what the equivalent number is for the automobile?

 

[[email protected]]

On 26 Apr 2006 05:32:23 -0700, "Mike Reed"
<[email protected]> wrote:

>
>[email protected] wrote:
>> Mike Reed wrote:
>> > Michael Press wrote:
>> > > ...they ride at 20+ miles / hour. ...
>> >
>> > That's a good point, but let's not forget that forward motion is only
>> > one component of melon velocity in a bike crash. If you collapsed from
>> > a standstill, you could still sustain a critical injury just from the
>> > acceleration of gravity.
>>
>> In this context, "could" is pretty weak. Practically speaking, nobody
>> ever does sustain a critical injury that way.
>
>Neither of us have any data to refute or support my assertion. However,
>practically speaking, what about a child falling off a nearly
>stationary bike? How about an elderly person? How about somebody who
>was riding slowly off-road, bumped their unhelmeted head off a tree
>limb, and fell unconcious to the rocks he was riding over?
>
>Just because it's rare doesn't mean it's not "practical."
>
>> When toppling off a
>> stationary bike, even if you somehow failed to break the fall with an
>> outstretched arm, you'd absorb most of the energy with your elbow and
>> shoulder.
>
>That's where the injury comes in. Your elbow and shoulder compress
>under the force of the fall, your neck bends, and your head accelerates
>like the end of a whip into the ground.
>
>> Practically speaking, you're as likely to suffer critical injury by
>> tripping over a sidewalk crack when walking.
>
>If you walk around holding a set of handlebars, I agree. You need a
>little initial distraction for your hands to start things off. Your
>feet are effectively taken out of the equation by your last step and
>the crack, so it's pretty similar.
>
>How about people falling from their feet on ice? That's more similar
>because it's a less familiar recovery than trip-falling you've been
>doing since you were 12 months old.
>
>> > Moving forward fast will add additional significant impacts, but that
>> > first one is pretty much just a function of falling over/sliding
>> > out/going over the bars/etc.
>>
>> Although the risk of serious HI is always low when biking, I think it's
>> significantly lower when not racing or training. The heat of
>> competition (even just for fun) makes guys much more likely to touch
>> wheels, or not notice the railroad track's flange slot, or run out of
>> road on a fast turn, etc.
>>
>> Slow cycling is, by any rational standard, boringly safe - despite all
>> the hype to the contrary.
>
>Critical injuries in general are relatively unlikely for an individual,
>so talking about how rarely some activity causes them is exercising the
>obvious.
>
>My whole point was not to forget the falling portion of a crash. The
>forward portion is still important, but the fall itself is dangerous,
>and that applies to anyone perched on one or two wheels, at any speed.
>
>-Mike

Dear Mike,

Actually, "just because it's rare" is often used to argue
against helmets.

Despite the tragedy below my signature (from my morning
newspaper), I doubt that anyone will be calling for women
over 60 to start wearing helmets to back their cars into the
alley.

I base my prediction on the fact that no one called for
pedestrian helmets last year when my retired fourth-grade
teacher tripped at the library, fell, hit her head, and died
a few days later.

On a less tragic note, it's worth pointing out that Simon
Brooke reported a similar incident:

"I've run over myself with my own car, does that help? 'Twas
a dark and stormy night, and I drove down to the shore to
check my boat. Parked at the top of the lane down to the
beach, leapt out, ran down the lane and stared out into the
tossing darkness; and the car, parking brake all unset,
sidled quietly down the lane and knocked me over..."

http://groups.google.com/group/rec.bicycles.tech/msg/87dc4a6d29e64bbf

Cheers,

Carl Fogel

Canon City woman, 81, killed in freak accident
By TRACY HARMON THE PUEBLO CHIEFTAIN

CANON CITY - A freak accident Friday that seriously injured
an 81-year-old woman led to her death Tuesday at a Pueblo
hospital.

Marian Kupau died as a result of head trauma, according to
Pueblo County Coroner James Kramer.

Canon City police reports indicate that a call was made
reporting an abandoned car which was discovered up against a
fence and still running in the alleyway behind 910 College
Ave. Police tried to find the owner of the vehicle, who
turned out to be Kupau, a resident of 825 Rudd, but she was
not at home.

During an investigation police learned that Kupau had been
discovered by a youth, who called for help. She was taken to
the Pueblo hospital for emergency treatment.

Police believe Kupau was attempting to back her car out of a
carport when she got out of the car without placing it in
park. The car struck her and knocked her down, causing her
to hit her head.

http://www.chieftain.com/metro/1146036523/17

 

[Mike Reed]

jtaylor wrote:

> Helmets don't work.

Darwin works. Happy riding.

 

[Ozark Bicycle]

Mike Reed wrote:
> jtaylor wrote:
>
> > Helmets don't work.
>
> Darwin works.


Only if the subject departs this mortal coil prior to passing on it's
genes. ;-)

(Someone who believes "helmets don't work" is apt to think the same
about condoms.)



> Happy riding.

 

[[email protected]]

On 26 Apr 2006 12:11:13 -0700, "Mike Kaiser"
<[email protected]> wrote:

>[email protected] wrote:
>
>> Er, let's see . . .1,000,000,000/25.9 = 38,610,038.61 km/UK
>> cyclist fatality, or 24 million miles.
>
>Does anyone know what the equivalent number is for the automobile?

Dear Mike,

A quick search found this page:

http://hazmat.dot.gov/riskmgmt/riskcompare.htm

For motor vehicles, 1.7 deaths / 100 million miles, with a
footnote that this is based on 1 fatality per 60 million
miles.

While this makes cars look almost twice as safe as bicycles,
it should be remembered that the average bicycle goes far
more slowly than the average car.

That is, the same daily commute might take three times as
long on a bicycle. An hour-long commute at 12 mph on a
bicycle might take only 20 minutes in a car at 36 mph.
(Obviously, that's a rough figure.)

If we convert the miles/fatality to hours/fatality at that
36mph/12mph rate, we get:

(60 million miles/car-fatality) / (36 mph) =

1.67 million hours/car-fatality

(24 million miles/bike-fatality) / (12 mph) =

2.00 million hours/bike-fatality

Now the rates look roughly equivalent to one side of the
debate, but the other side can argue that bicycles are still
clearly more dangerous than cars.

(I hope no one is foolish enough to use my crude
back-of-the-envelope calculation.)

There are all kinds of problems here. What's the real hourly
ratio? My 36-to-12 ratio is obviously open to question. Are
we comparing UK to US rates? Were they rates from different
times that have since changed? Heavy trucks are excluded,
which skews things. What about motorcycles, which have a
separate category?

Again, a good place to find out what sort of details are
involved in the debate is Guy Chapman's site:

http://www.chapmancentral.co.uk/web/public.nsf/Documents/maxi-faq-helmets#risks

Half the fun is finding out things that you wouldn't think
of on your own.

Cheers,

Carl Fogel

 

[Werehatrack]

On 26 Apr 2006 13:06:23 -0700, "Ozark Bicycle"
<[email protected]> wrote:

>
>Mike Reed wrote:
>> jtaylor wrote:
>>
>> > Helmets don't work.
>>
>> Darwin works.
>
>
>Only if the subject departs this mortal coil prior to passing on it's
>genes. ;-)
>
>(Someone who believes "helmets don't work" is apt to think the same
>about condoms.)

I, for one, have a very hard time accepting that "helmets don't work"
because in my very direct personal experience, they definitely do work
well enough to be worth using. But as the "no one should wear a
helmet because I think they're worthless" proponents have clearly
decided that they're right and everyone else is nuts, I'm content to
let them go their own way; they, however, seem determined not to let
me go mine in peace.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

 

[Sorni]

Werehatrack wrote:
> On 26 Apr 2006 13:06:23 -0700, "Ozark Bicycle"
> <[email protected]> wrote:
>
>>
>> Mike Reed wrote:
>>> jtaylor wrote:
>>>
>>>> Helmets don't work.
>>>
>>> Darwin works.
>>
>>
>> Only if the subject departs this mortal coil prior to passing on it's
>> genes. ;-)
>>
>> (Someone who believes "helmets don't work" is apt to think the same
>> about condoms.)

> I, for one, have a very hard time accepting that "helmets don't work"
> because in my very direct personal experience, they definitely do work
> well enough to be worth using. But as the "no one should wear a
> helmet because I think they're worthless" proponents have clearly
> decided that they're right and everyone else is nuts, I'm content to
> let them go their own way; they, however, seem determined not to let
> me go mine in peace.

Bingo. (BTW, I won't "share" a mountain bike ride with a helmetless rider;
don't care to see scrambled brains frying on rocks. Hasn't come up for any
road rides yet -- every single person I know wears a lid.)

BS

 

[John Forrest Tomlinson]

On 26 Apr 2006 08:56:45 -0700, "Mike Reed" <[email protected]>
wrote:

>[email protected] wrote:
>> > My whole point was not to forget the falling portion of a crash. The
>> > forward portion is still important, but the fall itself is dangerous,
>> > and that applies to anyone perched on one or two wheels, at any speed.
>>
>> <sigh> And perhaps anyone perched on two feet.
>>
>> "You there! Either get that walking helmet on, or get crawling!"
>
>You obviously have a wonderful opportunity to save yourself $189.00 in
>cycling gear by not wearing a helmet.

"It's not that expensive -- after all, how much is your head worth?"

"$49.99 plus shipping on closeout at Bike Nashbar."

JT

****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************

 

[[email protected]]

Werehatrack wrote:

> I, for one, have a very hard time accepting that "helmets don't work"
> because in my very direct personal experience, they definitely do work
> well enough to be worth using.

AFAIK, nobody doubts that helmets "work well enough" to help prevent
minor bumps and scrapes. If, for you, that justifies using one, that's
perfectly fine.

However, the promoters of bike helmets sell them by an entire different
set of claims. They claim they prevent almost all head injuries. They
sometimes claim bike helmets will save many, many lives per year. They
often imply bike helmets will keep many, many people from becoming
vegetables - or, as we saw just upthread, will allow people to live
long enough to pass on their genes.

These are much different claims than just "work well enough for me."
And its _these_ claims that have been proven thoroughly false. They're
proven false by examination of the effects of widespread helmet use.
Also proven false is the related claim that cycling is so dangerous
that the typical rider actually needs a helmet to cycle safely.

> But as the "no one should wear a
> helmet because I think they're worthless" proponents have clearly
> decided that they're right and everyone else is nuts,

Isn't it obvious that you're turning reality on its head? I've never
heard of a helmet skeptic trying to outlaw the use of helmets; but
there have been many helmet proponents working energetically to outlaw
riding without one! Obviously, those proponents have decided that
"everyone else" is nuts - so much so that they should not have the
legal freedom to make their own decision!

And, FWIW, in all the hundreds of thousands of face to face
interactions I've had with other cyclists, I've never told anyone they
should stop wearing a helmet. I've let them "go in peace," as you put
it. But I've had many people tell me that I _should_ wear a helmet.
IOW, they don't return the favor.

I'd be happy to drop this topic entirely - once choice of hat is
treated the same way as choice of riding shorts. But as long as we
have people misstating Darwin's ideas, and claiming that it's foolish
to ride without a helmet, and claiming that cycling is an extremely
hazardous activity, I'll keep presenting evidence to the contrary.
Those whose opinions aren't set in concrete can read the evidence and
decide for themselves.

- Frank Krygowski

 

[Mark Hickey]

"jtaylor" <[email protected]> wrote:

>Helmets don't work.

http://www.habcycles.com/bikecrash.html

I beg to differ. They certainly can.

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame

 

[Bestest Handsander]

"Mark Hickey" <[email protected]> wrote in message
news:[email protected]...
> "jtaylor" <[email protected]> wrote:
>
>>Helmets don't work.
>
> http://www.habcycles.com/bikecrash.html
>
> I beg to differ. They certainly can.
>
> Mark Hickey
> Habanero Cycles
> http://www.habcycles.com
> Home of the $795 ti frame

Wow! Great to hear you're alright. So, did the truck owner yell at you for
generally being a cyclist? Something along the lines of, "How dare you bend
my mirror bracket by smashing your head into it?!"

 

[Sorni]

Mark Hickey wrote:
> "jtaylor" <[email protected]> wrote:
>
>> Helmets don't work.

> http://www.habcycles.com/bikecrash.html
>
> I beg to differ. They certainly can.

Anecdotal. {pause}

J/K!!!

Sadly, some on here will say your helmet CAUSED or at least exacerbated your
injuries -- with a straight face (unlike yours after that!) even...

I have that exact Bell model lid; it's my favorite even though I paid more
for a fancy "Cratoni" (GRS) one recently...

Bill "and no, JFT, I ain't braggin' " S.

 

[Mike Jacoubowsky]

> I'd be happy to drop this topic entirely - once choice of hat is
> treated the same way as choice of riding shorts. But as long as we
> have people misstating Darwin's ideas, and claiming that it's foolish
> to ride without a helmet, and claiming that cycling is an extremely
> hazardous activity, I'll keep presenting evidence to the contrary.
> Those whose opinions aren't set in concrete can read the evidence and
> decide for themselves.

"Dangerous" is in the eye of the beholder. Cycling can be dangerous, just as
driving a car can be dangerous, just as hang gliding, or walking through
some neighborhoods etc. When in a car, people may feel safer than otherwise
because they have a ton of steel wrapped around them, seatbelts, and
airbags. All of those items have been proven to provide added safety to the
occupant. It's not unreasonable for somebody on a bicycle to look for
something similar (in terms of an external gadget or design of some sort
that provides added safety). Helmets fit that category. By extension, people
believe that others (cyclists) should benefit from added safety in the same
manner people require that cars be safer than might otherwise be the case.

I truly do not know if I'm arguing a case for, or against, bicycle helmets.
I think I have provided some rationale for why people have such
strongly-held beliefs for why people should wear them though.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


<[email protected]> wrote in message
news:[email protected]...
>
> Werehatrack wrote:
>
>> I, for one, have a very hard time accepting that "helmets don't work"
>> because in my very direct personal experience, they definitely do work
>> well enough to be worth using.
>
> AFAIK, nobody doubts that helmets "work well enough" to help prevent
> minor bumps and scrapes. If, for you, that justifies using one, that's
> perfectly fine.
>
> However, the promoters of bike helmets sell them by an entire different
> set of claims. They claim they prevent almost all head injuries. They
> sometimes claim bike helmets will save many, many lives per year. They
> often imply bike helmets will keep many, many people from becoming
> vegetables - or, as we saw just upthread, will allow people to live
> long enough to pass on their genes.
>
> These are much different claims than just "work well enough for me."
> And its _these_ claims that have been proven thoroughly false. They're
> proven false by examination of the effects of widespread helmet use.
> Also proven false is the related claim that cycling is so dangerous
> that the typical rider actually needs a helmet to cycle safely.
>
>> But as the "no one should wear a
>> helmet because I think they're worthless" proponents have clearly
>> decided that they're right and everyone else is nuts,
>
> Isn't it obvious that you're turning reality on its head? I've never
> heard of a helmet skeptic trying to outlaw the use of helmets; but
> there have been many helmet proponents working energetically to outlaw
> riding without one! Obviously, those proponents have decided that
> "everyone else" is nuts - so much so that they should not have the
> legal freedom to make their own decision!
>
> And, FWIW, in all the hundreds of thousands of face to face
> interactions I've had with other cyclists, I've never told anyone they
> should stop wearing a helmet. I've let them "go in peace," as you put
> it. But I've had many people tell me that I _should_ wear a helmet.
> IOW, they don't return the favor.
>
> I'd be happy to drop this topic entirely - once choice of hat is
> treated the same way as choice of riding shorts. But as long as we
> have people misstating Darwin's ideas, and claiming that it's foolish
> to ride without a helmet, and claiming that cycling is an extremely
> hazardous activity, I'll keep presenting evidence to the contrary.
> Those whose opinions aren't set in concrete can read the evidence and
> decide for themselves.
>
> - Frank Krygowski
>

 

[[email protected]]

On Thu, 27 Apr 2006 04:27:23 GMT, "Sorni"
<[email protected]> wrote:

>Mark Hickey wrote:
>> "jtaylor" <[email protected]> wrote:
>>
>>> Helmets don't work.
>
>> http://www.habcycles.com/bikecrash.html
>>
>> I beg to differ. They certainly can.
>
>Anecdotal. {pause}
>
>J/K!!!
>
>Sadly, some on here will say your helmet CAUSED or at least exacerbated your
>injuries -- with a straight face (unlike yours after that!) even...
>
>I have that exact Bell model lid; it's my favorite even though I paid more
>for a fancy "Cratoni" (GRS) one recently...
>
>Bill "and no, JFT, I ain't braggin' " S.

Dear Bill,

Can you tell us of any country whose bicycle head injury
trend rates changed to a significant degree during any
period in which bicycle helmet use increased by 50%?

That is, bicycle head injury rates trend gently downward
over time, but I know of no country in which massive
increases in helmet wearing have been accompanied by any
change in the gentle downward trend.

Here's a typical graph at half-year intervals showing
bicycle head injuries and helmet use, with a third line
showing non-bicycle head injuries:

http://www.chapmancentral.co.uk/web/public.nsf/b383cda8149ed78680256aaa00603759

No one could guess from the gently delcining bicycle head
injury rate that helmet use had risen from near 0% to almost
100% in New Zealand from March 1988 to March 1994.

And even the gentle downward trend in head injuries for
cyclists is not likely to be due to helmets, since it
practically mirrors the gentle downward trend in head
injuries for non-cyclists, who didn't start wearing helmets.

More details on that example and others can be found here:

http://www.chapmancentral.co.uk/web/public.nsf/Documents/maxi-faq-helmets?OpenDocument

That's why even dramatic examples aren't quite as convincing
as you'd expect them to be. Anyone looking at Mark's
pictures and description of his accident can certainly be
excused for assuming that his helmet saved him and that
helmets must therefore have a widespread and similar effect.

But no such widespread effect seems to show up. Either
there's something wrong with our assumptions about such
individual accidents, or else there's something amazing
missing from the nationwide bicycling accident statistics
for country after country, year after year.

When what we expect from individual cases fails to show up
in the general population, the individual cases are usually
found to be anecdotal, mis-interpreted, or somehow not
nearly as applicable as we thought.

A great deal of medicine, for example, depends on wide-scale
testing of what seems to be perfectly reasonable and even
works in small trials. The wide-scale testing has a nasty
habit of showing that the theory and limited testing gave a
false prediction.

Cheers,

Carl Fogel