Re: I crash into religion - Page 5

Re: I crash into religion

"Ozark Bicycle" > wrote in message > Mike Sales wrote:
> > "Ozark Bicycle" wrote in message
>
> Just to be clear: I did *not* write:
>
> > >> > Because the risk of head injury per trip is lower while walking?
> > > >
> > > >
> > >
> I did write:
>
>
> > > ....and I don't walk down twisty descents at ~35-40mph?
> >
> > And..
> > John Forrest Tomlinson wrote:
> >
> > > in a typical solo bike crash, the
> > > cyclists goes skidding or tumbling. But the cyclist's speed *toward
> > > the ground* is a lot less than 35mph. It's often not that different
> > > than a fall at low speed.
> >
> > Ozark agreed
> >
> > "Exactly."
> >
> >
> >
> And??
>
I thought your inconsistency was obvious, and that having it pointed out
that you are prepared to use any argument to support your position, whether
or not it contradicts one you previously used, would be embarrassing to you.
This was silly of me.
You say, that helmets are needed when cycling because one rides at 35
mph sometimes. Then you say ( or agree ) that a fall at this speed is often
not that different to a fall at low speed.
Mike Sales

Re: I crash into religion

In article <4d1anlF17sm2vU1@individual.net>, junk@raven-family.com
says...
> Espressopithecus (Java Man) wrote:
>
> > I agree that cycling is not very dangerous. And I disagree with
> > mandatory helmet laws, at least for adults. I don't know about the
> > stats for children.
>
> The UK stats for children is that three times as many are murdered by
> close friends or relatives compared with cycling accidents. Perhaps we
> should have mandatory taking into care in the UK
>
> > What I've been saying on this thread and others is
> > that those who make the gross assumption that population stats tell us
> > that ANYONE who wears a helmet is increasing his risk of head injury are
> > misusing the data. It's ironic to see this argument coming from those
> > who accuse MHL proponents of using faulty data to support their crusade.
> >
>
> The population stats tell you you are more likely to be increasing your
> risk by wearing a helmet.

Ignoring, of course, that helmets may be more protective in some types
of crashes and less in others. And ignoring that some individuals may
be more likely to have some types of crashes than others. And ignoring
risk compensation by those who know helmets are less likely to provide
protection in certain circumstances. Hmm -- a lot of ignoring is needed
to support that conclusion.

> Now you may be a very cautious rider which
> means you will minimise the chance of you having an accident in the
> first place but 90% of the deaths or serious injuries are caused by
> being hit by a motor vehicle. Will your caution change the way the
> driver drives and the speed and position of the impact? So in the vast
> majority of accidents you will be no different from anyone else because
> events are not in your control - if they were you would have avoided the
> accident in the first place.
>
> If you had an illness and the doctor offered you a pill that he said had
> performed well in limited clinical trials but that recent studies had
> shown that there was a worrying number of deaths in people on the pill
> would you take the pill and say, "I'll be alright doc, I'm not other
> people"?
>
I would be less worried if I knew that 90% of those who died were, say,
diabetics and I wasn't. Of course, we can't let those pesky details get
in the way of a good generalization, now can we?

Rick

Re: I crash into religion

In article <0Id*s0Tgr@news.chiark.greenend.org.uk>,
damerell@chiark.greenend.org.uk says...
> Quoting Espressopithecus (Java Man) <rickk@letterectomyTELUS.net>:
> >You are applying population statistics to an individual, which is an
> >error in logic. We do not know the underlying risk distribution for
> >individuals in the population, nor do we know the underlying risk
> >variance.
>
> Surely if we don't know that then we can use the population statistics.

Not to predict risk for specific individuals -- unless you think
individual risk propensity is all clustered around a very narrow, peaky
distribution curve with a very low sigma. Until the stats break out
subgroups based on km ridden per year, age, marital status, etc, I don't
think you can sensibly say anything about helmets and risk for
individuals. The data supports the proposition that MHLs have been a
mistake. It doesn't support the conclusion that specific individuals
are better off with or without a helmet.

> Only if we had some information about the individual's peculiarities and
> how they affect risk - and when we talk about, say, the relative odds of
> direct or tangential impacts, that's hard to know - do the population
> statistics become of limited use.

Which is exactly why I included the parts you snipped to make your
point. I WAS talking about individuals and their differences from the
population statistics.

Rick

Re: I crash into religion

Espressopithecus (Java Man) wrote:
>
> Ignoring, of course, that helmets may be more protective in some types
> of crashes and less in others.

Which and what types of crashes are those and where is the evidence?

> And ignoring that some individuals may
> be more likely to have some types of crashes than others.

Which individuals and what types of crashes are those and where is the
evidence?

> And ignoring
> risk compensation by those who know helmets are less likely to provide
> protection in certain circumstances.

Which individuals and what circumstances are those and where is the evidence


> Hmm -- a lot of ignoring is needed
> to support that conclusion.
>

Yes, like ignoring the fact that you are missing lots of information to
tell you whether you are in a "safe" group or "at risk" group


>>
>> If you had an illness and the doctor offered you a pill that he said had
>> performed well in limited clinical trials but that recent studies had
>> shown that there was a worrying number of deaths in people on the pill
>> would you take the pill and say, "I'll be alright doc, I'm not other
>> people"?
>>
> I would be less worried if I knew that 90% of those who died were, say,
> diabetics and I wasn't. Of course, we can't let those pesky details get
> in the way of a good generalization, now can we?
>

But you don't know that and you don't know what it was about those
people that led to their deaths, only that they died.


--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

Re: I crash into religion

In article
<mo6sj3-bm9.ln1@gododdin.internal.jasmine.org.uk>,
Simon Brooke <simon@jasmine.org.uk> wrote:

> Lesson two: when you've had a crash and you're jumping with adrenaline,
> and your friends say 'lie still and we'll call an ambulance', lie still
> and let them call an ambulance. Getting back on your bike and riding
> another mile isn't clever.

-- Are you OK?
-- No.

--
Michael Press

Re: I crash into religion

In article <4d1c87F187v9tU1@individual.net>, junk@raven-family.com
says...
> Espressopithecus (Java Man) wrote:
> >
> > Ignoring, of course, that helmets may be more protective in some types
> > of crashes and less in others.
>
> Which and what types of crashes are those and where is the evidence?

The evidence on this is not firm because not enough studies have been
done. But my reading suggests that in lower speed crashes helmets may
be more effective than none, while in higher speed crashes, they may be
less effective than none.
>
> > And ignoring that some individuals may
> > be more likely to have some types of crashes than others.
>
> Which individuals and what types of crashes are those and where is the
> evidence?

I don't have statistics on this. Failing that, I assume that all
cyclists are equally NOT likely crash on a per-km ridden basis. Do you
dispute this assumption?
>
> > And ignoring
> > risk compensation by those who know helmets are less likely to provide
> > protection in certain circumstances.
>
> Which individuals and what circumstances are those and where is the evidence

Again, no statistics, but if all cyclists risk compensate, those who
know helmets may not protect them in certain circumstances will ride
differently than those who don't know this.
>
>
> > Hmm -- a lot of ignoring is needed
> > to support that conclusion.
> >
>
> Yes, like ignoring the fact that you are missing lots of information to
> tell you whether you are in a "safe" group or "at risk" group

Would you ignore all these factors in making your own personal
decisions, instead relying on a simple whole population statistic?
>
>
> >>
> >> If you had an illness and the doctor offered you a pill that he said had
> >> performed well in limited clinical trials but that recent studies had
> >> shown that there was a worrying number of deaths in people on the pill
> >> would you take the pill and say, "I'll be alright doc, I'm not other
> >> people"?
> >>
> > I would be less worried if I knew that 90% of those who died were, say,
> > diabetics and I wasn't. Of course, we can't let those pesky details get
> > in the way of a good generalization, now can we?
> >
>
> But you don't know that and you don't know what it was about those
> people that led to their deaths, only that they died.
>
I'm sure you feel free to make your own judgements about when to let
statistics influence your decisions and when not. I certainly do.

Rick

Re: I crash into religion

in message <MPG.1ed52010571da377989792@shawnews.vc.shawcable.net>,
Espressopithecus (Java Man) ('rickk@letterectomyTELUS.net') wrote:

> In article <4d1c87F187v9tU1@individual.net>, junk@raven-family.com
> says...
>> Espressopithecus (Java Man) wrote:
>> >
>> > Ignoring, of course, that helmets may be more protective in some
>> > types of crashes and less in others.
>>
>> Which and what types of crashes are those and where is the evidence?
>
> The evidence on this is not firm because not enough studies have been
> done. But my reading suggests that in lower speed crashes helmets may
> be more effective than none, while in higher speed crashes, they may be
> less effective than none.

That's certainly my belief. But more evidence would be welcome.

--
simon@jasmine.org.uk (Simon Brooke) http://www.jasmine.org.uk/~simon/

'You cannot put "The Internet" into the Recycle Bin.'

Re: I crash into religion

Tony Raven wrote:
>
> The population stats tell you you are more likely to be increasing
> your risk by wearing a helmet.

That is one possible explanation of the population stats - but there are
others.

If the pre - post MHL cycling populations have different characteristics &
we know they change because some people stop cycling,
then it is possible that those stopping are low mileage/occasional cyclists
leaving the post MHL population more heavily weighted with high mileage-high
traffic cyclists.
Now we know that risk/accidents are more likely the result of driver error
than cyclist error, then on the introduction of a MHL rule you would expect
to see an increase in the risk per cyclist if there were zero or even
moderately positive benefit from a helmet.

I don't know, you don't know (and the CTC says it doesn't know) what the
correct interpretation of the population level data is, but you are wrong to
take it as a given that your preferred explanation is the only one possible.

pk

Re: I crash into religion

p.k. wrote:
> Tony Raven wrote:
>> The population stats tell you you are more likely to be increasing
>> your risk by wearing a helmet.
>
> That is one possible explanation of the population stats - but there are
> others.
>
> If the pre - post MHL cycling populations have different characteristics &
> we know they change because some people stop cycling,
> then it is possible that those stopping are low mileage/occasional cyclists
> leaving the post MHL population more heavily weighted with high mileage-high
> traffic cyclists.
> Now we know that risk/accidents are more likely the result of driver error
> than cyclist error, then on the introduction of a MHL rule you would expect
> to see an increase in the risk per cyclist if there were zero or even
> moderately positive benefit from a helmet.
>
> I don't know, you don't know (and the CTC says it doesn't know) what the
> correct interpretation of the population level data is, but you are wrong to
> take it as a given that your preferred explanation is the only one possible.
>

Lets take your proposition and for the sake of argument assume its true.
You would agree that the number of cyclists has dropped so you would
expect the number of head injuries to drop for that reason and the
remaining high mileage cyclists are all now wearing helmets and should
be having less head injuries in the remaining accidents if helmets are
effective? Yes?

So you should easily be able to see the step downwards in the number of
head injuries at the time the helmet law was introduced? Yes?

OK, so now take the test that, every time I have posed it to helmet
supporters, they have all studiously ignored and avoided taking. On
http://www.cycling.raven-family.com/Helmet%20Graphs.jpg I have
reproduced the graphs of absolute head injury numbers in two countries
that have introduced helmet laws. So identify for me at which
horizontal tick mark the helmet law was introduced in each graph. It
should be very easy, just look for the downward step in head injuries.

Go on, be the first helmet supporter to dare to take the test (without
cheating and looking up the answer).

--
Tony

"The best way I know of to win an argument is to start by being in the
right."
- Lord Hailsham

Re: I crash into religion

In article <rfdsj3-rei.ln1@gododdin.internal.jasmine.org.uk>,
simon@jasmine.org.uk says...
> in message <MPG.1ed518b7b24d479598978f@shawnews.vc.shawcable.net>,
> Espressopithecus (Java Man) ('rickk@letterectomyTELUS.net') wrote:
>
> >>
> >> The population stats tell you you are more likely to be increasing
> >> your risk by wearing a helmet.
> >
> > Ignoring, of course, that helmets may be more protective in some types
> > of crashes and less in others.
>
> Yes, they may, and in fact almost certainly are. But until we
> know /which/ sorts of crashes those are, it's pretty unsafe to advise
> other people to wear helmets, don't you think?
>
Did I advise someone to wear a helmet?

Rick

Re: Question for Frank Krygowski

On 17 May 2006 12:23:05 -0700, "Ozark Bicycle"
<bicycleatelier@ozarkbicycleservice.com> wrote:

>
>frkrygow@gmail.com wrote:
>
><snipped>
>>
>> http://www.bicyclinglife.com
>>
>>
>
>On this site, you aver that some communities have limited bicycle
>traffic to sidewalks.
>
>IIRC, bicycles are given the same access to and responsibilities on
>roadways as is other traffic. It only took a few seconds to find a
>source that reinforced my recollection:
>
>http://tinyurl.com/rjrsy
>
>See the 14th paragraph:
>
>"Traffic laws in every US state....allows cyclists to travel on
>roadways in travel lanes as vehicle operators."
>
>Can you provide a reference to the communities limiting bicycles to the
>sidewalks?

Dear Oz,

I don't know of whole cities with bikes restricted to sidewalks,
but in Colorado bicycles are forbidden to use lots of roads:

(11) Where suitable bike paths, horseback trails, or other trails
have been established on the right-of-way or parallel to and
within one-fourth mile of the right-of-way of heavily traveled
streets and highways, the department of transportation may,
subject to the provisions of section 43-2-135, C.R.S., by
resolution or order entered in its minutes, and local authorities
may, where suitable bike paths, horseback trails, or other trails
have been established on the right-of-way or parallel to it
within four hundred fifty feet of the right-of-way of heavily
traveled streets, by ordinance, determine and designate, upon the
basis of an engineering and traffic investigation, those heavily
traveled streets and highways upon which shall be prohibited any
bicycle, animal rider, animal-drawn conveyance, or other class or
kind of nonmotorized traffic which is found to be incompatible
with the normal and safe movement of traffic, and, upon such a
determination, the department of transportation or local
authority shall erect appropriate official signs giving notice
thereof; except that with respect to controlled access highways
the provisions of section 42-4-1010 (3) shall apply. When such
official signs are so erected, no person shall violate any of the
instructions contained thereon.

http://198.187.128.12/colorado/lpext...ced&2.0#LPHit1

In theory, this means that bicycles can be forbidden only on
heavy-traffic roads.

In practice, this means that if I turn north when I reach the
Pueblo Dam, I'm forbidden to use the road and must use the
separate bike path that runs through hundred-foot dips below the
road.

If I turn south, I still occasionally have to explain to cops
that there are no bicycles-prohibited signs south of the river.

The road is through a state park, with the same speed limit in
both directions.

Cheers,

Carl Fogel

Re: I crash into religion

Tony Raven wrote:
>>
>
> Lets take your proposition and for the sake of argument assume its
> true. You would agree that the number of cyclists has dropped so you
> would expect the number of head injuries to drop for that reason and
> the remaining high mileage cyclists are all now wearing helmets and
> should be having less head injuries in the remaining accidents if
> helmets are effective? Yes?
>


I'm not going to get caught up in the fine detail of a not fully though out
scenario - I only put it forward to demonstrate that there are other
*possible* explanations than your posited:
"The population stats tell you you are more likely to be increasing your
risk by wearing a helmet"



> So you should easily be able to see the step downwards in the number
> of head injuries at the time the helmet law was introduced? Yes?
>
> OK, so now take the test that, every time I have posed it to helmet
> supporters, they have all studiously ignored and avoided taking. On
> http://www.cycling.raven-family.com/Helmet%20Graphs.jpg I have
> reproduced the graphs of absolute head injury numbers in two countries
> that have introduced helmet laws. So identify for me at which
> horizontal tick mark the helmet law was introduced in each graph. It
> should be very easy, just look for the downward step in head injuries.
>
> Go on, be the first helmet supporter to dare to take the test (without
> cheating and looking up the answer).

Flawed test! You would only expect a step change if you went from no MHL to
fully complied MHL overnight & with no prior warning.
There is no dispute ( from me) that the effect/benefit is smaller than is
often claimed, I would not expect to be able to see any clear change on
noisy data with many confounding variables.
Strip out the cases involving accident at speeds well beyond the design spec
of the helmet and we might see something

pk

Re: Question for Frank Krygowski

Ozark Bicycle wrote:
> frkrygow@gmail.com wrote:
>
> <snipped>
> >
> > http://www.bicyclinglife.com
> >
> >
>
> On this site, you aver that some communities have limited bicycle
> traffic to sidewalks.
>
> IIRC, bicycles are given the same access to and responsibilities on
> roadways as is other traffic. It only took a few seconds to find a
> source that reinforced my recollection:
>
> http://tinyurl.com/rjrsy
>
> See the 14th paragraph:
>
> "Traffic laws in every US state....allows cyclists to travel on
> roadways in travel lanes as vehicle operators."
>
> Can you provide a reference to the communities limiting bicycles to the
> sidewalks?

Here's one reference. http://www.crankmail.com/fredoswald/tour.html

- Frank Krygowski