Energy absorption and cycle helmets

[Derek C]

Those of you who follow Formula One motor racing may have seen an
horrendous looking crash in the European Grand Prix on Sunday, when
Mark Webber's Red Bull car was flipped upside down and then careered
at almost undimished speed into a tyre barrier set at 90 degrees to
the direction in which he was going. Despite a very heavy impact, the
tyre barrier absorbed the energy, so that the car was little further
damaged and Mark stepped out unhurt. See:

http://www.youtube.com/watch?v=adotu1JU8PA

The EPS foam in a cycle helmet does a basically similar job to a tyre
wall in absorbing energy. Therefore you are less likely to suffer a
fractured skull or traumatic brain injury, should your head hit
something hard, such as a vehicle, road surface or kerbstone.

I thought that the video showed the tyre wall compressing to absorb
the energy particularly well. The air bubbles in EPS foam will do
exactly the same sort of thing.

Derek C

[bugbear]

Derek C wrote:
> Those of you who follow Formula One motor racing may have seen an
> horrendous looking crash in the European Grand Prix on Sunday, when
> Mark Webber's Red Bull car was flipped upside down and then careered
> at almost undimished speed into a tyre barrier set at 90 degrees to
> the direction in which he was going. Despite a very heavy impact, the
> tyre barrier absorbed the energy, so that the car was little further
> damaged and Mark stepped out unhurt. See:
>
> http://www.youtube.com/watch?v=adotu1JU8PA
>
> The EPS foam in a cycle helmet does a basically similar job to a tyre
> wall in absorbing energy. Therefore you are less likely to suffer a
> fractured skull or traumatic brain injury, should your head hit
> something hard, such as a vehicle, road surface or kerbstone.
>
> I thought that the video showed the tyre wall compressing to absorb
> the energy particularly well. The air bubbles in EPS foam will do
> exactly the same sort of thing.

The principles are well known, and not in dispute (so extra
evidence isn't really very useful).

Absorbers in "tend to absorb" shock!

We just had a large, and quite detailed thread
about the circumstances under which such energy
absorptions makes a effective difference
in the outcome of an incident, and wether this
out weighs any negative consequences
of providing the absorbers.

One could conclude from the same incident that the same
harnesses used in formula one cars should immediately
be fitted to all vehicles, and their use made compulsory.

More safety can only be a Good Thing.

BugBear

[Derek C]

On Jun 28, 5:07*pm, bugbear > wrote:
> Derek C wrote:
> > Those of you who follow Formula One motor racing may have seen an
> > horrendous looking crash in the European Grand Prix on Sunday, when
> > Mark Webber's Red Bull car was flipped upside down and then careered
> > at almost undimished speed into a tyre barrier set at 90 degrees to
> > the direction in which he was going. Despite a very heavy impact, the
> > tyre barrier absorbed the energy, so that the car was little further
> > damaged and Mark stepped out unhurt. See:
>
> > *http://www.youtube.com/watch?v=adotu1JU8PA
>
> > The EPS foam in a cycle helmet does a basically similar job to a tyre
> > wall in absorbing energy. Therefore you are less likely to suffer a
> > fractured skull or traumatic brain injury, should your head hit
> > something hard, such as a vehicle, road surface or kerbstone.
>
> > I thought that the video showed the tyre wall compressing to absorb
> > the energy particularly well. The air bubbles in EPS foam will do
> > exactly the same sort of thing.
>
> The principles are well known, and not in dispute (so extra
> evidence isn't really very useful).
>
> Absorbers in "tend to absorb" shock!
>
> We just had a large, and quite detailed thread
> about the circumstances under which such energy
> absorptions makes a effective difference
> in the outcome of an incident, and wether this
> out weighs any negative consequences
> of providing the absorbers.
>
> One could conclude from the same incident that the same
> harnesses used in formula one cars should immediately
> be fitted to all vehicles, and their use made compulsory.
>

As bikes and motorbikes tend to fall over sideways if you lose
control, and have no protective structure, I'm not sure that seat
harnesses would help very much. Perhaps something to stop you going
over the handlebars if you stop suddenly might be a good idea. All
modern cars are fitted with seat belts that are perfectly adequate for
everyday speeds, and have a protective steel cage.

I very much doubt that Mark Webber would have walked away from that
accident if that tyre barrier hadn't been there. He would have at
least suffered broken legs, even with a full harness seat belt.

Derek C

[Ian Smith]

On Mon, 28 Jun 2010 09:38:16, Derek C > wrote:
>
> I very much doubt that Mark Webber would have walked away from that
> accident if that tyre barrier hadn't been there. He would have at
> least suffered broken legs, even with a full harness seat belt.

So now you propose mandatory tyre-walls at every corner on every road?

--
|\ /| no .sig
|o o|
|/ \|

[Derek C]

On Jun 28, 7:46*pm, Ian Smith > wrote:
> On Mon, 28 Jun 2010 09:38:16, Derek C > wrote:
>
> > *I very much doubt that Mark Webber would have walked away from that
> > *accident if that tyre barrier hadn't been there. He would have at
> > *least suffered broken legs, even with a full harness seat belt.
>
> So now you propose mandatory tyre-walls at every corner on every road?
>

No, just energy absorbing helmets to be worn by cyclists on a
voluntary basis. By the way, Mark Webber considers himself very lucky
to be alive and uninjured after that crash. See:

http://news.bbc.co.uk/sport1/hi/motorsport/formula_one/8766344.stm

Derek C

[Bill]

"Ian Smith" > wrote in message
. ..
> On Mon, 28 Jun 2010 09:38:16, Derek C > wrote:
>>
>> I very much doubt that Mark Webber would have walked away from that
>> accident if that tyre barrier hadn't been there. He would have at
>> least suffered broken legs, even with a full harness seat belt.
>
> So now you propose mandatory tyre-walls at every corner on every road?

It would solve the problem of how to dispose of millions of worn out
tyres...............

[Tosspot[_3_]]

On 28/06/10 16:27, Derek C wrote:
> Those of you who follow Formula One motor racing may have seen an
> horrendous looking crash in the European Grand Prix on Sunday, when
> Mark Webber's Red Bull car was flipped upside down and then careered
> at almost undimished speed into a tyre barrier set at 90 degrees to
> the direction in which he was going. Despite a very heavy impact, the
> tyre barrier absorbed the energy, so that the car was little further
> damaged and Mark stepped out unhurt. See:
>
> http://www.youtube.com/watch?v=adotu1JU8PA
>
> The EPS foam in a cycle helmet does a basically similar job to a tyre
> wall in absorbing energy. Therefore you are less likely to suffer a
> fractured skull or traumatic brain injury, should your head hit
> something hard, such as a vehicle, road surface or kerbstone.
>
> I thought that the video showed the tyre wall compressing to absorb
> the energy particularly well. The air bubbles in EPS foam will do
> exactly the same sort of thing.

Indeed, all cyclists should wear the same helmets as F1 drivers, and, if
possible, only cycle in cycle lanes that are protected by tyre walls.
Recumbent riders will of course already have monocoques.

Car drivers of course don't need to bother, because as Webber
demonstrated, you don't need all that **** driving a car.

1/10 must try harder.

[Squashme]

On 28 June, 20:10, Derek C > wrote:
> On Jun 28, 7:46*pm, Ian Smith > wrote:
>
> > On Mon, 28 Jun 2010 09:38:16, Derek C > wrote:
>
> > > *I very much doubt that Mark Webber would have walked away from that
> > > *accident if that tyre barrier hadn't been there. He would have at
> > > *least suffered broken legs, even with a full harness seat belt.
>
> > So now you propose mandatory tyre-walls at every corner on every road?
>
> No, just energy absorbing helmets to be worn by cyclists on a
> voluntary basis. By the way, Mark Webber considers himself very lucky
> to be alive and uninjured after that crash. See:
>
> http://news.bbc.co.uk/sport1/hi/motorsport/formula_one/8766344.stm
>
> Derek C

Thanks for the advice. I'm certainly going to avoid cycling at 200 mph
in the future, you can be sure.

[DavidR[_2_]]

"Derek C" > wrote
>
> I thought that the video showed the tyre wall compressing to absorb
> the energy particularly well. The air bubbles in EPS foam will do
> exactly the same sort of thing.

Air is very elastic under compression and compression of the air will not
the
mechanism by which helmets absorb energy.

A tyre wall is also elastic which can be seen by the car bouncing back. The
properties of a single chamber of air (forming a nearly lossless spring) is
what has made pneumatic tyres so succesful compared to solid or cellular
alternatives.

For low rolling resistance, casing and rubber losses are also designed out
as much as possible. In that respect, that's why Michelin patented steel
bracing - until the patent ran out in 1985, other manufacturers had to make
do with lossy textiles.

So tyres and helmets have quite different properties.

[Derek C]

On Jun 29, 12:20*am, "DavidR" > wrote:
> "Derek C" > wrote
>
>
>
> > I thought that the video showed the tyre wall compressing to absorb
> > the energy particularly well. The air bubbles in EPS foam will do
> > exactly the same sort of thing.
>
> Air is very elastic under compression and compression of the air will not
> the
> mechanism by which helmets absorb energy.
>
> A tyre wall is also elastic which can be seen by the car bouncing back. The
> properties of a single chamber of air (forming a nearly lossless spring) is
> what has made pneumatic tyres so succesful compared to solid or cellular
> alternatives.
>
> For low rolling resistance, casing and rubber losses are also designed out
> as much as possible. In that respect, that's why Michelin patented steel
> bracing - until the patent ran out in 1985, other manufacturers had to make
> do with lossy textiles.
>
> So tyres and helmets have quite different properties.

Both tyre walls and EPS helmets are designed to brings things to a
more gentle, less damaging halt in a crash than would otherwise be the
case. Tyre walls are not totally ideal because there is some elastic
rebound; as you can see in the video Mark Webber's car does bounce
back a few feet after the impact. However old tyres are an economic
way of providing an energy absorbing barrier.

The EPS foam in helmets will crush under load without rebounding,
which is why it is an ideal material for its purpose.

I see that I have got all the expected sarcastic replies from the
helmet sceptics!

Derek C

[bugbear]

Tosspot wrote:
> On 28/06/10 16:27, Derek C wrote:
>> Those of you who follow Formula One motor racing may have seen an
>> horrendous looking crash in the European Grand Prix on Sunday, when
>> Mark Webber's Red Bull car was flipped upside down and then careered
>> at almost undimished speed into a tyre barrier set at 90 degrees to
>> the direction in which he was going. Despite a very heavy impact, the
>> tyre barrier absorbed the energy, so that the car was little further
>> damaged and Mark stepped out unhurt. See:
>>
>> http://www.youtube.com/watch?v=adotu1JU8PA
>>
>> The EPS foam in a cycle helmet does a basically similar job to a tyre
>> wall in absorbing energy. Therefore you are less likely to suffer a
>> fractured skull or traumatic brain injury, should your head hit
>> something hard, such as a vehicle, road surface or kerbstone.
>>
>> I thought that the video showed the tyre wall compressing to absorb
>> the energy particularly well. The air bubbles in EPS foam will do
>> exactly the same sort of thing.
>
> Indeed, all cyclists should wear the same helmets as F1 drivers, and, if
> possible, only cycle in cycle lanes that are protected by tyre walls.
> Recumbent riders will of course already have monocoques.
>
> Car drivers of course don't need to bother, because as Webber
> demonstrated, you don't need all that **** driving a car.
>
> 1/10 must try harder.

I think it also demonstrates risk compensation.

Given all this safety equipment, formula 1 drivers
have been seen driving VERY fast.

BugBear

[bugbear]

Derek C wrote:
>
> I see that I have got all the expected sarcastic replies from the
> helmet sceptics!

If you post "what is 2+2" you will
probably get a lot of "4" replies.

BugBear

[Derek C]

On Jun 29, 9:15*am, bugbear > wrote:
> Tosspot wrote:
> > On 28/06/10 16:27, Derek C wrote:
> >> Those of you who follow Formula One motor racing may have seen an
> >> horrendous looking crash in the European Grand Prix on Sunday, when
> >> Mark Webber's Red Bull car was flipped upside down and then careered
> >> at almost undimished speed into a tyre barrier set at 90 degrees to
> >> the direction in which he was going. Despite a very heavy impact, the
> >> tyre barrier absorbed the energy, so that the car was little further
> >> damaged and Mark stepped out unhurt. See:
>
> >> *http://www.youtube.com/watch?v=adotu1JU8PA
>
> >> The EPS foam in a cycle helmet does a basically similar job to a tyre
> >> wall in absorbing energy. Therefore you are less likely to suffer a
> >> fractured skull or traumatic brain injury, should your head hit
> >> something hard, such as a vehicle, road surface or kerbstone.
>
> >> I thought that the video showed the tyre wall compressing to absorb
> >> the energy particularly well. The air bubbles in EPS foam will do
> >> exactly the same sort of thing.
>
> > Indeed, all cyclists should wear the same helmets as F1 drivers, and, if
> > possible, only cycle in cycle lanes that are protected by tyre walls.
> > Recumbent riders will of course already have monocoques.
>
> > Car drivers of course don't need to bother, because as Webber
> > demonstrated, you don't need all that **** driving a car.
>
> > 1/10 must try harder.
>
> I think it also demonstrates risk compensation.
>
> Given all this safety equipment, formula 1 drivers
> have been seen driving VERY fast.
>
> * * BugBear- Hide quoted text -
>
So can you ride your pedal cycle at 200mph then? Even allowing for
risk compensation, motor racing has become very much safer than it was
twenty or thirty years ago, due to various technical safety measures
such as better helmets. Back in the 1950s and 1960's maybe 20 drivers
a year were killed in the various formulas, but it is now rare to get
even one.

Derek C

[David[_11_]]

"Derek C" > wrote in message
...
> > So now you propose mandatory tyre-walls at every corner on every road?
> >
>
> No, just energy absorbing helmets to be worn by cyclists on a
> voluntary basis.

They are.

[Paul - xxx[_2_]]

On 28/06/2010 20:10, Derek C wrote:
> On Jun 28, 7:46 pm, Ian > wrote:
>> On Mon, 28 Jun 2010 09:38:16, Derek > wrote:
>>
>>> I very much doubt that Mark Webber would have walked away from that
>>> accident if that tyre barrier hadn't been there. He would have at
>>> least suffered broken legs, even with a full harness seat belt.
>>
>> So now you propose mandatory tyre-walls at every corner on every road?
>>
>
> No, just energy absorbing helmets to be worn by cyclists on a
> voluntary basis.

They often are, that's the thing with voluntary, you don't have to.

I mostly wear one off-road, but rarely on-road.

--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi
Dyna Tech Cro-Mo comp

[Derek C]

On Jun 29, 10:39*am, Paul - xxx > wrote:
> On 28/06/2010 20:10, Derek C wrote:
>
> > On Jun 28, 7:46 pm, Ian > *wrote:
> >> On Mon, 28 Jun 2010 09:38:16, Derek > *wrote:
>
> >>> * I very much doubt that Mark Webber would have walked away from that
> >>> * accident if that tyre barrier hadn't been there. He would have at
> >>> * least suffered broken legs, even with a full harness seat belt.
>
> >> So now you propose mandatory tyre-walls at every corner on every road?
>
> > No, just energy absorbing helmets to be worn by cyclists on a
> > voluntary basis.
>
> They often are, that's the thing with voluntary, you don't have to.
>
> I mostly wear one off-road, but rarely on-road.
>
> --
I understand that only about 33% of cyclists on the road wear cycle
helmets. I regularly use a rural road in Hampshire that is much used
by cycling groups or clubs. ALL of them wear cycle helmets and it
often looks like the poor man's version of the Tour de France.

Derek C

[Peter Clinch]

Derek C wrote:

> I understand that only about 33% of cyclists on the road wear cycle
> helmets. I regularly use a rural road in Hampshire that is much used
> by cycling groups or clubs. ALL of them wear cycle helmets and it
> often looks like the poor man's version of the Tour de France.

Welcome to the wonderful world of group behaviour.

Who you're with and the perceived nature of the excursion will play a
large role in what is worn. In the UK, cyclists will typically want to
be perceived as serious cyclists making a choice to have All The Right
Gear. Due to the level of misinformation about helmets in the UK (for
example, last week the BBC had a story suggesting it was illegal not to
wear one) it's not entirely surprising that a helmet is widely
considered part of "All The Right Gear" (it was certainly part and
parcel of why I always used to wear one). In the UK it's common for
cyclists to want to make a statement that they are serious about it. My
(Dutch) wife never realised she was "a cyclist" until she came to the
UK, it would be a bit like being labelled as "a pedestrian" would be
here to suggest it's some sort of lifestyle choice in NL.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

[Derek C]

On Jun 29, 11:20*am, Peter Clinch > wrote:
> Derek C wrote:
> > I understand that only about 33% of cyclists on the road wear cycle
> > helmets. I regularly use a rural road in Hampshire that is much used
> > by cycling groups or clubs. ALL of them wear cycle helmets and it
> > often looks like the poor man's version of the Tour de France.
>
> Welcome to the wonderful world of group behaviour.
>
> Who you're with and the perceived nature of the excursion will play a
> large role in what is worn. *In the UK, cyclists will typically want to
> be perceived as serious cyclists making a choice to have All The Right
> Gear. *Due to the level of misinformation about helmets in the UK (for
> example, last week the BBC had a story suggesting it was illegal not to
> wear one) it's not entirely surprising that a helmet is widely
> considered part of "All The Right Gear" (it was certainly part and
> parcel of why I always used to wear one). *In the UK it's common for
> cyclists to want to make a statement that they are serious about it. *My
> (Dutch) wife never realised she was "a cyclist" until she came to the
> UK, it would be a bit like being labelled as "a pedestrian" would be
> here to suggest it's some sort of lifestyle choice in NL.
>
> Pete.

Most of the misinformation seems to come from the <cyclehelmets.org>
website of the Bicycle Helmet Research Foundation. Fortunately 33% of
all cyclists and nearly 100% of the serious ones have either not read
it, or dismiss it for the nonsense that it is.

Derek C

[Paul - xxx[_2_]]

On 29/06/2010 11:08, Derek C wrote:
> On Jun 29, 10:39 am, Paul - > wrote:
>> On 28/06/2010 20:10, Derek C wrote:
>>
>>> On Jun 28, 7:46 pm, Ian > wrote:
>>>> On Mon, 28 Jun 2010 09:38:16, Derek > wrote:
>>
>>>>> I very much doubt that Mark Webber would have walked away from that
>>>>> accident if that tyre barrier hadn't been there. He would have at
>>>>> least suffered broken legs, even with a full harness seat belt.
>>
>>>> So now you propose mandatory tyre-walls at every corner on every road?
>>
>>> No, just energy absorbing helmets to be worn by cyclists on a
>>> voluntary basis.
>>
>> They often are, that's the thing with voluntary, you don't have to.
>>
>> I mostly wear one off-road, but rarely on-road.
>>
>> --
> I understand that only about 33% of cyclists on the road wear cycle
> helmets. I regularly use a rural road in Hampshire that is much used
> by cycling groups or clubs. ALL of them wear cycle helmets and it
> often looks like the poor man's version of the Tour de France.

I also might wear a helmet if I'm going to cycle in a group. My
reasoning would be that there's more chance of a multiple pile-up and
subsequent chances of 'something' hitting me on the head.

--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi
Dyna Tech Cro-Mo comp

[Paul - xxx[_2_]]

On 29/06/2010 11:27, Derek C wrote:

> Most of the misinformation seems to come from the<cyclehelmets.org>
> website of the Bicycle Helmet Research Foundation. Fortunately 33% of
> all cyclists and nearly 100% of the serious ones have either not read
> it, or dismiss it for the nonsense that it is.

By that definition there isn't much misinformation then ..

--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi
Dyna Tech Cro-Mo comp

[Peter Clinch]

Derek C wrote:

> Most of the misinformation seems to come from the <cyclehelmets.org>
> website of the Bicycle Helmet Research Foundation.

Of course it's a dominant force in information provision on the
matter... yeah, right.

> Fortunately 33% of
> all cyclists and nearly 100% of the serious ones have either not read
> it, or dismiss it for the nonsense that it is.

How can you be sure its nonsense without actually reading the source
material it comments on?

You might be well served by the 2007 article Chris Boardman wrote in Pro
Cycling, in which mag he'd been accused by many readers for being shown
"irresponsibly" without one while testing bikes. While noting (not
immodestly) his own reputation for getting to the bottom of things very
thoroughly he proceeded to outline the research that you can't be
bothered to read that showed the common myth among a lot of wannabe
racers that helmets make a significant safety difference to be on rather
shaky ground.

But, hey! why read actual work on the topic when you can make sweeping
assumptions based on gut feelings while pretending that access to a
library is some sort of undeserved privilege of no real account as
opposed to the place to get started in many scholarly endeavours?

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

[Derek C]

On Jun 29, 12:12*pm, Peter Clinch > wrote:
> Derek C wrote:
> > Most of the misinformation seems to come from the <cyclehelmets.org>
> > website of the Bicycle Helmet Research Foundation.
>
> Of course it's a dominant force in information provision on the
> matter... yeah, right.
>
> > Fortunately 33% of
> > all cyclists and nearly 100% of the serious ones have either not read
> > it, or dismiss it for the nonsense that it is.
>
> How can you be sure its nonsense without actually reading the source
> material it comments on?
>
> You might be well served by the 2007 article Chris Boardman wrote in Pro
> Cycling, in which mag he'd been accused by many readers for being shown
> "irresponsibly" without one while testing bikes. *While noting (not
> immodestly) his own reputation for getting to the bottom of things very
> thoroughly he proceeded to outline the research that you can't be
> bothered to read that showed the common myth among a lot of wannabe
> racers that helmets make a significant safety difference to be on rather
> shaky ground.
>
> But, hey! *why read actual work on the topic when you can make sweeping
> assumptions based on gut feelings while pretending that access to a
> library is some sort of undeserved privilege of no real account as
> opposed to the place to get started in many scholarly endeavours?
>

I can still spot dodgy use of statistics when I see it.

Derek C

[bugbear]

Derek C wrote:
> On Jun 29, 12:12 pm, Peter Clinch > wrote:
>> Derek C wrote:
>>> Most of the misinformation seems to come from the <cyclehelmets.org>
>>> website of the Bicycle Helmet Research Foundation.
>> Of course it's a dominant force in information provision on the
>> matter... yeah, right.
>>
>>> Fortunately 33% of
>>> all cyclists and nearly 100% of the serious ones have either not read
>>> it, or dismiss it for the nonsense that it is.
>> How can you be sure its nonsense without actually reading the source
>> material it comments on?
>>
>> You might be well served by the 2007 article Chris Boardman wrote in Pro
>> Cycling, in which mag he'd been accused by many readers for being shown
>> "irresponsibly" without one while testing bikes. While noting (not
>> immodestly) his own reputation for getting to the bottom of things very
>> thoroughly he proceeded to outline the research that you can't be
>> bothered to read that showed the common myth among a lot of wannabe
>> racers that helmets make a significant safety difference to be on rather
>> shaky ground.
>>
>> But, hey! why read actual work on the topic when you can make sweeping
>> assumptions based on gut feelings while pretending that access to a
>> library is some sort of undeserved privilege of no real account as
>> opposed to the place to get started in many scholarly endeavours?
>>
>
> I can still spot dodgy use of statistics when I see it.

How do you spot dodgy statistics in things you haven't read?

Tricky...

BugBear

[Peter Clinch]

Derek C wrote:

> I can still spot dodgy use of statistics when I see it.

With brilliant flashes like on balance more work says helmets are
effective than otherwise is enough to convince, and you've seen a
correlation but have made no effort at all to verify if it's causal
beyond it suits you, your own posts /should/ be setting off the alarm
bells left right and centre.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

[Paul - xxx[_2_]]

On 29/06/2010 12:29, Derek C wrote:

> I can still spot dodgy use of statistics when I see it.

Like the 'psycholists' thread where you introduced a set of stats which
included pedestrian casualties, then when someone else produced a
different set you said ..

"Hence comparisons with pedestrian casualties are not really valid."

It would seem you have a flawed viewpoint that moves goalposts a tad,
and then back pedals when asked further questions, somewhat like Doug .....


--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi
Dyna Tech Cro-Mo comp

[Derek C]

On Jun 29, 1:06*pm, Paul - xxx > wrote:
> On 29/06/2010 12:29, Derek C wrote:
>
> > I can still spot dodgy use of statistics when I see it.
>
> Like the 'psycholists' thread where you introduced a set of stats which
> included pedestrian casualties, then when someone else produced a
> different set you said ..
>
> "Hence comparisons with pedestrian casualties are not really valid."
>
> It would seem you have a flawed viewpoint that moves goalposts a tad,
> and then back pedals when asked further questions, somewhat like Doug ......
>
> --
> Paul - xxx
>
> '96/'97 Landrover Discovery 300 Tdi
> Dyna Tech Cro-Mo comp

In terms of reported road accidents, cyclists have about twice the
risk of being killed or seriously injured than pedestrians. I still
don't thank that pedestrians are an effective control group to assess
the effectiveness of helmets in preventing serious head and facial
injuries, because they don't travel nearly as fast and are less
exposed to vehicular traffic. Remember that most of them walk on the
footpath most of the time (if they have any sense that is) which is a
different environment.

I am told by the sceptics that I mustn't use correlations without
proving causation, such as me claiming that increasing use of helmets
has reduced cycling KSI figures over time, but they claim that because
pedestrian casualties have also fallen in the same period that
disproves the case. They can't have it both ways!

Derek C

[Just zis Guy, you know?[_2_]]

On Jun 29, 1:59*pm, Derek C > wrote:

> In terms of reported road accidents, cyclists have about twice the
> risk of being killed or seriously injured than pedestrians.

You'll need a source for that. Severity ratios and accurate measure of
exposure would be required in order to make such a statement.
--
Guy

[Peter Clinch]

Derek C wrote:

> In terms of reported road accidents, cyclists have about twice the
> risk of being killed or seriously injured than pedestrians. I still
> don't thank that pedestrians are an effective control group to assess
> the effectiveness of helmets in preventing serious head and facial
> injuries, because they don't travel nearly as fast and are less
> exposed to vehicular traffic.

But it's the speed and mass of the motor vehicle that'll do for you, not
that of the bike. Or the shoes.

> Remember that most of them walk on the
> footpath most of the time (if they have any sense that is) which is a
> different environment.

But it's on the road (for the most part) they get killed or seriously
injured. Often when they're not on a driver's radar having just
appeared from the pavement they're not bothered about, as opposed to
being a predictable part of the traffic on the road that they are
bothered about (a bit like cycle tracks just concentrate more casualties
at junctions between tracks and roads rather than make you safer). It's
not total exposure that's the problem for pedestrians, it's a sudden
spike in risk as soon as they step off the pavement.

Before you rule out pedestrians as a potential control you need to
determine why, at least in the UK, pedestrian and cyclist casualty
trends have always historically tracked one another. And your
arm-waving above doesn't help you, because it's getting hit by motor
vehicles on roads that gets most cyclists /and/ pedestrians into the
STATS19 figures.

> I am told by the sceptics that I mustn't use correlations without
> proving causation, such as me claiming that increasing use of helmets
> has reduced cycling KSI figures over time

That's right.

> but they claim that because
> pedestrian casualties have also fallen in the same period that
> disproves the case.

Nobody's saying it disproves the case, they're saying it's a clear
confounding factor that must be accounted for. And as yet you haven't
accounted for it.

> They can't have it both ways!

"They" are not trying to, because "they" are in the easier position of
saying you've not got the info for a safe conclusion. *You* are the
have-your-cake-and-eat-it merchant here.

Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net http://www.dundee.ac.uk/~pjclinch/

[Ian Smith]

On Tue, 29 Jun 2010 04:29:12 -0700 (PDT), Derek C > wrote:
>
> I can still spot dodgy use of statistics when I see it.

That's the best laugh I've had all day, thank you.


--
|\ /| no .sig
|o o|
|/ \|

[Derek C]

On Jun 29, 2:18*pm, Peter Clinch > wrote:
> Derek C wrote:
> > In terms of reported road accidents, cyclists have about twice the
> > risk of being killed or seriously injured than pedestrians. I still
> > don't thank that pedestrians are an effective control group to assess
> > the effectiveness of helmets in preventing serious head and facial
> > injuries, because they don't travel nearly as fast and are less
> > exposed to vehicular traffic.
>
> But it's the speed and mass of the motor vehicle that'll do for you, not
> that of the bike. *Or the shoes.
>
> > Remember that most of them walk on the
> > footpath most of the time (if they have any sense that is) which is a
> > different environment.
>
> But it's on the road (for the most part) they get killed or seriously
> injured. *Often when they're not on a driver's radar having just
> appeared from the pavement they're not bothered about, as opposed to
> being a predictable part of the traffic on the road that they are
> bothered about (a bit like cycle tracks just concentrate more casualties
> at junctions between tracks and roads rather than make you safer). *It's
> not total exposure that's the problem for pedestrians, it's a sudden
> spike in risk as soon as they step off the pavement.
>
> Before you rule out pedestrians as a potential control you need to
> determine why, at least in the UK, pedestrian and cyclist casualty
> trends have always historically tracked one another. *And your
> arm-waving above doesn't help you, because it's getting hit by motor
> vehicles on roads that gets most cyclists /and/ pedestrians into the
> STATS19 figures.
>
> > I am told by the sceptics that I mustn't use correlations without
> > proving causation, such as me claiming that increasing use of helmets
> > has reduced cycling KSI figures over time
>
> That's right.
>
> > *but they claim that because
> > pedestrian casualties have also fallen in the same period that
> > disproves the case.
>
> Nobody's saying it disproves the case, they're saying it's a clear
> confounding factor that must be accounted for. *And as yet you haven't
> accounted for it.

The reduction in pedestrian casualties is probably due to a better
infracture and more separation of pedestrians from vehicular traffic
due to railings and subways. More light controlled crossings have been
installed. Cars now have better ABS brakes, smoother shapes, crumple
zones and are a bit more pedestrian friendly in a collision with one.
Many people who might have walked in the past now drive cars. Medical
science has improved.

Is that enough good reasons to account for this reduction?
>
> > They can't have it both ways!
>
> "They" are not trying to, because "they" are in the easier position of
> saying you've not got the info for a safe conclusion. **You* are the
> have-your-cake-and-eat-it merchant here.
>
Neither have the helmet sceptics. Many responsible bodies including
the TRL, RoSPA and the BMA think that helmets are a good idea.

Derek C

[Paul - xxx[_2_]]

On 29/06/2010 13:59, Derek C wrote:
> On Jun 29, 1:06 pm, Paul - > wrote:
>> On 29/06/2010 12:29, Derek C wrote:
>>
>>> I can still spot dodgy use of statistics when I see it.
>>
>> Like the 'psycholists' thread where you introduced a set of stats which
>> included pedestrian casualties, then when someone else produced a
>> different set you said ..
>>
>> "Hence comparisons with pedestrian casualties are not really valid."
>>
>> It would seem you have a flawed viewpoint that moves goalposts a tad,
>> and then back pedals when asked further questions, somewhat like Doug ......
>
> In terms of reported road accidents, cyclists have about twice the
> risk of being killed or seriously injured than pedestrians. I still
> don't thank that pedestrians are an effective control group to assess
> the effectiveness of helmets in preventing serious head and facial
> injuries, because they don't travel nearly as fast and are less
> exposed to vehicular traffic. Remember that most of them walk on the
> footpath most of the time (if they have any sense that is) which is a
> different environment.
>
> I am told by the sceptics that I mustn't use correlations without
> proving causation, such as me claiming that increasing use of helmets
> has reduced cycling KSI figures over time, but they claim that because
> pedestrian casualties have also fallen in the same period that
> disproves the case. They can't have it both ways!

Whooosh ...

Who asked about the actual stats? I commented on your use then denial
of relevancy on one set.

Your inconsistency doesn't bolster your credibility much.

--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi
Dyna Tech Cro-Mo comp

[Colin McKenzie]

On Tue, 29 Jun 2010 13:59:23 +0100, Derek C >
wrote:

> In terms of reported road accidents, cyclists have about twice the
> risk of being killed or seriously injured than pedestrians.

The figures you yourself gave are:
KSI per billion passenger kilometres:
Bus or Coach 9, Car 20, Pedestrian 382, Pedal Cycle 541, ...

That's about a 40% greater chance, not double. And the killed figures
differ by a similar percentage, but the other way. In other words, you
trade a lower chance of serious injury for a higher chance of death, if
you walk instead of cycling.

> I still
> don't thank that pedestrians are an effective control group to assess
> the effectiveness of helmets in preventing serious head and facial
> injuries, because they don't travel nearly as fast and are less
> exposed to vehicular traffic. Remember that most of them walk on the
> footpath most of the time (if they have any sense that is) which is a
> different environment.

About 100 a year killed on the footpath, I think.

The recorded road casualty figures almost all involve one or more
vehicles. Pedestrians may not be a perfect control group, but they're the
best available and the risks come from the same source - motor vehicles.

> I am told by the sceptics that I mustn't use correlations without
> proving causation, such as me claiming that increasing use of helmets
> has reduced cycling KSI figures over time, but they claim that because
> pedestrian casualties have also fallen in the same period that
> disproves the case. They can't have it both ways!

Eh? Casualty rate reductions track each other over time. The cyclist
helmet-wearing rate has changed, the pedestrian helmet-wearing rate
hasn't. You are saying that some unknown factor, that only applies to
pedestrians, by an extraordinary coincidence is causing similar casualty
reductions to those produced by helmets for cyclists.

Actually, cyclists seem to be doing slightly worse than pedestrians over
the last 10 or so years. If I were to argue that that is a consequence of
increased helmet-wearing making cycle casualties worse, I would have as
much justification as you have in arguing that cycle helmets help - i.e.
not a lot.

Colin McKenzie

--
No-one has ever proved that cycle helmets make cycling any safer at the
population level, and anyway cycling is about as safe per mile as walking.
Make an informed choice - visit www.cyclehelmets.org.

[Derek C]

On Jun 29, 4:49*pm, Paul - xxx > wrote:
> On 29/06/2010 13:59, Derek C wrote:
>
>
>
>
>
> > On Jun 29, 1:06 pm, Paul - > *wrote:
> >> On 29/06/2010 12:29, Derek C wrote:
>
> >>> I can still spot dodgy use of statistics when I see it.
>
> >> Like the 'psycholists' thread where you introduced a set of stats which
> >> included pedestrian casualties, then when someone else produced a
> >> different set you said ..
>
> >> "Hence comparisons with pedestrian casualties are not really valid."
>
> >> It would seem you have a flawed viewpoint that moves goalposts a tad,
> >> and then back pedals when asked further questions, somewhat like Doug .......
>
> > In terms of reported road accidents, cyclists have about twice the
> > risk of being killed or seriously injured than pedestrians. I still
> > don't thank that pedestrians are an effective control group to assess
> > the effectiveness of helmets in preventing serious head and facial
> > injuries, because they don't travel nearly as fast and are less
> > exposed to vehicular traffic. Remember that most of them walk on the
> > footpath most of the time (if they have any sense that is) which is a
> > different environment.
>
> > I am told by the sceptics that I mustn't use correlations without
> > proving causation, such as me claiming that increasing use of helmets
> > has reduced cycling KSI figures over time, but they claim that because
> > pedestrian casualties have also fallen in the same period that
> > disproves the case. They can't have it both ways!
>
> Whooosh ...
>
> Who asked about the actual stats? *I commented on your use then denial
> of relevancy on one set.
>
> Your inconsistency doesn't bolster your credibility much.
>
> --
> Paul - xxx
>
> '96/'97 Landrover Discovery 300 Tdi
> Dyna Tech Cro-Mo comp- Hide quoted text -
>
> - Show quoted text -

You are attacking me purely because I am in favour of wearing cycle
helmets. A typical psycholist!

Derek C

[Just zis Guy, you know?[_2_]]

On Tue, 29 Jun 2010 07:20:24 -0700 (PDT), Derek C
> wrote:

>Many responsible bodies including
>the TRL, RoSPA and the BMA think that helmets are a good idea.

Logical fallacy: appeal to authority. We have had an opportunity to
examine their reasoning in some cases, and it turns out to be based on
exactly the same poor evidence as your opinion, with exactly the same
failure to account for conflicting evidence.

RoSPA have not always been so dim, mind - in an assessment of the
likely effect of measures to improve cycle safety, they put
engineering improvements to the cycle, including helmets, last.

Guy
--
http://www.chapmancentral.co.uk/
The usenet price promise: all opinions offered in newsgroups are guaranteed
to be worth the price paid.

[Just zis Guy, you know?[_2_]]

On Tue, 29 Jun 2010 15:06:42 -0700 (PDT), Derek C
> wrote:

>You are attacking me purely because I am in favour of wearing cycle
>helmets. A typical psycholist!

This response marks you out as a worthless case. Your *arguments* are
attacked because they are fallacious, weak or plain wrong, and using
pejoratives in this way is a classic religious gambit: the ungodly
attack me because I believe, typical heathens.

It's not the first time you've done this. It often seems to coincide
with your having painted yourself into yet another corner.

Let me put it more clearly: you're attacking Paul purely because you
are unable to best him in debate. A typical ****.

Guy
--
http://www.chapmancentral.co.uk/
The usenet price promise: all opinions offered in newsgroups are guaranteed
to be worth the price paid.

[Derek C]

On Jun 29, 11:23*pm, "Just zis Guy, you know?"
> wrote:
> On Tue, 29 Jun 2010 15:06:42 -0700 (PDT), Derek C
>
> > wrote:
> >You are attacking me purely because I am in favour of wearing cycle
> >helmets. A typical psycholist!
>
> This response marks you out as a worthless case. Your *arguments* are
> attacked because they are fallacious, weak or plain wrong, and using
> pejoratives in this way is a classic religious gambit: the ungodly
> attack me because I believe, typical heathens.
>
> It's not the first time you've done this. It often seems to coincide
> with your having painted yourself into yet another corner.
>
> Let me put it more clearly: you're attacking Paul purely because you
> are unable to best him in debate. A typical ****.
>
As you are resorting to personal insults, I have to assume that your
case is weak!

Derek C

[Tony Raven[_3_]]

Derek C wrote:

>> > wrote:
>>> A typical psycholist!

<....>

> As you are resorting to personal insults, I have to assume that your
> case is weak!
>

Oh the irony!!!

--
Tony

" I would never die for my beliefs because I might be wrong."
Bertrand Russell

[David[_11_]]

"Derek C" > wrote in message
...
> > You are attacking me purely because I am in favour of wearing cycle
> > helmets. A typical psycholist!
>
> As you are resorting to personal insults, I have to assume that your
> case is weak!

Was 'psycholist' a complement?

D

[Paul - xxx[_2_]]

On 29/06/2010 23:06, Derek C wrote:

> You are attacking me purely because I am in favour of wearing cycle
> helmets. A typical psycholist!

Where have I said that? I'm attacking you for inconsistency in your
arguments, it's got nothing to do with the actual debate .. you have a
flawed base from which you're arguing.

--
Paul - xxx

'96/'97 Landrover Discovery 300 Tdi
Dyna Tech Cro-Mo comp

[Just zis Guy, you know?[_2_]]

On Tue, 29 Jun 2010 16:36:59 -0700 (PDT), Derek C
> wrote:

>On Jun 29, 11:23*pm, "Just zis Guy, you know?"
> wrote:
>> On Tue, 29 Jun 2010 15:06:42 -0700 (PDT), Derek C
>>
>> > wrote:
>> >You are attacking me purely because I am in favour of wearing cycle
>> >helmets. A typical psycholist!
>>
>> This response marks you out as a worthless case. Your *arguments* are
>> attacked because they are fallacious, weak or plain wrong, and using
>> pejoratives in this way is a classic religious gambit: the ungodly
>> attack me because I believe, typical heathens.
>>
>> It's not the first time you've done this. It often seems to coincide
>> with your having painted yourself into yet another corner.
>>
>> Let me put it more clearly: you're attacking Paul purely because you
>> are unable to best him in debate. A typical ****.
>>
>As you are resorting to personal insults, I have to assume that your
>case is weak!

As previously noted, you plainly have no sense of irony whatever. You
also need to work on your comprehension skills and learn some
self-criticism otherwise you're going to keep laying yourself open to
the kind of flaying you're getting from Tony and Ian. Not that I mind
too much, I find it quite amusing to watch.

Guy
--
http://www.chapmancentral.co.uk/
The usenet price promise: all opinions offered in newsgroups are guaranteed
to be worth the price paid.

[Ian Smith]

On Wed, 30 Jun 2010, Paul - xxx > wrote:
> On 29/06/2010 23:06, Derek C wrote:
>
> > You are attacking me purely because I am in favour of wearing
> > cycle helmets. A typical psycholist!
>
> Where have I said that? I'm attacking you for inconsistency in your
> arguments, it's got nothing to do with the actual debate .. you have a
> flawed base from which you're arguing.

Derek finds it expedient to maintain that everyone thinks he's an
idiot because they can't face the truth that he alone promulgates.

Obviously there is no possible alternative explanation for the
observation that everyone who tries to engage with him rapidly
decides he is an idiot.

--
|\ /| no .sig
|o o|
|/ \|

[JMS]

On Tue, 29 Jun 2010 12:12:31 +0100, Peter Clinch
> wrote:

>Derek C wrote:
>
>> Most of the misinformation seems to come from the <cyclehelmets.org>
>> website of the Bicycle Helmet Research Foundation.
>
>Of course it's a dominant force in information provision on the
>matter... yeah, right.
>
>> Fortunately 33% of
>> all cyclists and nearly 100% of the serious ones have either not read
>> it, or dismiss it for the nonsense that it is.
>
>How can you be sure its nonsense without actually reading the source
>material it comments on?
>
>You might be well served by the 2007 article Chris Boardman wrote in Pro
>Cycling, in which mag he'd been accused by many readers for being shown
>"irresponsibly" without one while testing bikes.


He's so against them that he promotes them and sells them on his
web-site.

Perhaps he doesn't know that they are a waste of time.


--
Many cyclists are proving the need for registration by their contempt for the Highway Code and laws.

The answer:
All cyclists over 16 to take compulsory test, have compulsory insurance, and be registered.
Registration number to be clearly visible on the back of mandatory hi-viz vest.
Habitual law breakers' cycles confiscated and crushed.
(With thanks to KeithT for the idea)

[JMS]

On Tue, 29 Jun 2010 06:08:47 -0700 (PDT), "Just zis Guy, you know?"
> wrote:

>On Jun 29, 1:59*pm, Derek C > wrote:
>
>> In terms of reported road accidents, cyclists have about twice the
>> risk of being killed or seriously injured than pedestrians.
>
>You'll need a source for that. Severity ratios and accurate measure of
>exposure would be required in order to make such a statement.


If you look at the DfT stats it is pretty obvious that cycling as a
means of transport is more dangerous than walking:

2008 DfT Figures: Passenger casualty rates Per billion passenger
kilometers:

Killed or seriously injured: Pedal Cyclists : 541 Pedestrians 382
All casualties: Pedal Cyclists : 3814 Pedestrians : 1666


--

I have never said that I encourage my children to wear helmets.
I would challenge judith to find the place where I said I encourage my children to wear helmets.
I encourage my children to wear helmets. (Guy Chapman)

[The Medway Handyman[_2_]]

David wrote:
> "Derek C" > wrote in message
> ...
>>> You are attacking me purely because I am in favour of wearing cycle
>>> helmets. A typical psycholist!
>>
>> As you are resorting to personal insults, I have to assume that your
>> case is weak!
>
> Was 'psycholist' a complement?

Just a very accurate description.


--
Dave - intelligent enough to realise that a push bike is a kid's toy, not a
viable form of transport.

[The Medway Handyman[_2_]]

Just zis Guy, you know? wrote:
> On Tue, 29 Jun 2010 16:36:59 -0700 (PDT), Derek C
> > wrote:

>
> As previously noted, you plainly have no sense of irony whatever. You
> also need to work on your comprehension skills and learn some
> self-criticism otherwise you're going to keep laying yourself open to
> the kind of flaying you're getting from Tony and Ian. Not that I mind
> too much, I find it quite amusing to watch.

**** me. No argument left. You have him by the balls Derek!

Have you also noticed that these cyclict ****s, when faced by an argument
they can't counter, always resort to claiming that you "need to work on
your comprehension skills" and "learn some self-criticism" etc"?

Then they claim that everyone else agrees with them. Then they try to claim
you are slagging them off when they have spent to last two paragraphs doing
the same thing.

Last resort is to try & claim the high ground by using patronising phrases
like "I find it quite amusing to watch" - as if this makes their argument
more valid.

And they use sigs like "Just zis Guy, you know"? which makes them look like
even bigger *******.


--
Dave - intelligent enough to realise that a push bike is a kid's toy, not a
viable form of transport.

[The Medway Handyman[_2_]]

Ian Smith wrote:
> On Wed, 30 Jun 2010, Paul - xxx > wrote:
>> On 29/06/2010 23:06, Derek C wrote:
>>
>>> You are attacking me purely because I am in favour of wearing
>>> cycle helmets. A typical psycholist!
>>
>> Where have I said that? I'm attacking you for inconsistency in your
>> arguments, it's got nothing to do with the actual debate .. you
>> have a flawed base from which you're arguing.
>
> Derek finds it expedient to maintain that everyone thinks he's an
> idiot because they can't face the truth that he alone promulgates.
>
> Obviously there is no possible alternative explanation for the
> observation that everyone who tries to engage with him rapidly
> decides he is an idiot.

I'm afraid there is an entirely valid alternative explanation. The ****s
who try to argue with him are complete ****wits - constantly repeating the
cyclicts mantra.

The Psycholists argument breaks down to "safety helmets are unsafe" which is
clearly stupidity of the highest order.

Their real argument is "you can't make me do anything, I'm special, mummy
told me I was, I can do whatever I like".

Thats one reason why they all argue against regulation. The other is that
regulation leads to taxation - which causes their arseholes to pucker.


--
Dave - intelligent enough to realise that a push bike is a kid's toy, not a
viable form of transport.