Re: baffling

Adrian said:

spindrift (spindrift <[email hidden]>😉 gurgled happily, sounding
much like they were saying:

Quoted message said:

To do this pupils need to become familiar and confident in their
application of the equation 1/2 mv2

Finally, we get to a different - and this time correct - equation.

Shame it assumes neither driver or pedestrian are paying any attention,
and that therefore the collision is inevitable.

ITYF that Paul Smith was completely in agreement with the majority of
u.r.d in saying that the focus, shared by you, on speed instead of
attention is what causes collisions.

No such assumption is made.

Speed is the single most important factor in road safety as the links
demonstrate. Reduce speed and accident rates plummet. Look at Hull.

spindrift (spindrift <[email hidden]>😉 gurgled happily, sounding
much like they were saying:

Quoted message said:

Eliminating all deaths from the roads is what Sweden are attempting
though, with astounding success:

Shame they're still worse than the UK, despite MASSIVELY lower traffic
volumes.

If you think road conditions in Sweden and the UK are in any way
comparable, you've never been to Sweden.

spindrift (spindrift <[email hidden]>😉 gurgled happily, sounding
much like they were saying:

Quoted message said:

Quoted message said:

Quoted message said:

To do this pupils need to become familiar and confident in their
application of the equation 1/2 mv2

Quoted message said:

Quoted message said:

Finally, we get to a different - and this time correct - equation.

Shame it assumes neither driver or pedestrian are paying any attention,
and that therefore the collision is inevitable.

Quoted message said:

No such assumption is made.

Of course it is. It has to be, else the free-moving traffic speed is
irrelevant, in favour of the speed at impact, which will vary widely from
the same free-moving speed, dependent on driver attention.

Quoted message said:

Reduce speed and accident rates plummet.

Shame the national focus on "Speed Kills" seems to be proving the exact
opposite.

spindrift said:

For every 1% reduction in average traffic speed, crashes reduce by an
average of 5% (Taylor et al, TRL 421, 2000).

Wasn't it for every 1 *mph* reduction, not for every 1%?

OK, let's use that formula to tabulate how the number of crashes that
would occur in Central London would be affected if we reduced the
average speed. Transport Statistic GB 2006 gives the average traffic
speed in Central London in 2003-06 as about 11 mph off-peak. Assuming
100% accidents at 11 mph we get:

Speed Crashes
mph %
----- -------
11 100
10 95
9 90
8 86
7 81
6 77
5 74
4 70
3 66
2 63
1 60
0 57

What have we just proved? (clue: it *isn't* that 57% of accidents would
still occur even if all vehicles were permanently stationary in London).

--
Matt B

In article <7b4babf7-e8b9-437a-b268-
[email hidden]>, spindrift says...

Quoted message said:

(SteveH) said:

spindrift said:

On 22 Dec, 15:14, [email hidden] (SteveH) wrote:
> spindrift <[email hidden]> wrote:
> > > Do you *honestly* believe that driving at 29mph is safer than driving at
> > > 30mph?
> > Of course.

Quoted message said:

> > You understand basic physics:

Quoted message said:

> > Force (N) = mass (kg) ? acceleration (m/s2)

Quoted message said:

> Go-on, then.

Quoted message said:

> If you're so clever, please tell us all what difference there will be in
> the acceleration rate of a person hit by a car doing 29mph rather than
> 30mph.

Quoted message said:

> Obviously, you've failed to take into account the error tolerances in
> all these calculations, which mean that a 1mph decrease in speed isn't
> actually a measurable difference.

Quoted message said:

Mass?

Quoted message said:

Use the formula.

The formula doesn't really help.

If you can find a way to show a significant difference using the
formula, please enlighten us.

However, the 1mph difference in the speed of the car could easily be
compensated for by the difference in speed of other objects hit.

--
SteveH 'You're not a real petrolhead unless you've owned an Alfa Romeo'www.italiancar.co.uk- Honda VFR800 - Hongdou GY200 - Alfa 75 TSpark
Alfa 156 TSpark - B6 Passat 2.0TDI SE - COSOC KOTL
BOTAFOT #87 - BOTAFOF #18 - MRO # - UKRMSBC #7 - Apostle #2 - YTC #- Hide quoted text -

- Show quoted text -

Someone send out for a 16 year old school pupil:

You need to understand the science behind why the impact of a car
travelling at 40mph upon a pedestrian is about four times more likely
to kill the pedestrian than an impact with the same cart at 30mph.

The thread was discussing 2MPH increments...

--
Conor

I'm not prejudiced. I hate everyone equally.

In article <7b4babf7-e8b9-437a-b268-
[email hidden]>, spindrift says...

Quoted message said:

You need to understand the science behind why the impact of a car
travelling at 40mph upon a pedestrian is about four times more likely
to kill the pedestrian than an impact with the same cart at 30mph.

Too simplistic. It takes no account of the type of impact and
pedestrian safety features built into the vehicle.

For example, being hit head on by a fairly new car in such a manner
that your head hits the bonnet will result in far less damage to a
person than an older car due to the fact that there is now an increased
gap between the bonnet and the top of the engine which allows for more
deformity and dispersal of forces involved.

--
Conor

I'm not prejudiced. I hate everyone equally.

Adrian said:

spindrift (spindrift <[email hidden]>😉 gurgled happily, sounding
much like they were saying:

Quoted message said:

Quoted message said:

> To do this pupils need to become familiar and confident in their
> application of the equation 1/2 mv2
Finally, we get to a different - and this time correct - equation.

Quoted message said:

Quoted message said:

Shame it assumes neither driver or pedestrian are paying any attention,
and that therefore the collision is inevitable.

No such assumption is made.

Of course it is. It has to be, else the free-moving traffic speed is
irrelevant, in favour of the speed at impact, which will vary widely from
the same free-moving speed, dependent on driver attention.

Quoted message said:

Reduce speed and accident rates plummet.

Shame the national focus on "Speed Kills" seems to be proving the exact
opposite.

The impact doesn't differ in a 30mph collision, as posted above.It's a
30mph collision, nothing else. The claim was made that one mph faster
will not make any difference, the understanding of physics that 16
year olds are expected to display makes it clear this is nonsense.

Adrian said:

spindrift (spindrift <[email hidden]>😉 gurgled happily, sounding
much like they were saying:

Quoted message said:

Eliminating all deaths from the roads is what Sweden are attempting
though, with astounding success:

Shame they're still worse than the UK, despite MASSIVELY lower traffic
volumes.

If you think road conditions in Sweden and the UK are in any way
comparable, you've never been to Sweden.

I never said they were. Argue with what I've said.

And Sweden's roads are safer than the UK:

http://www.lboro.ac.uk/service/publicity/news-releases/2007/81_road_safety.html

The UK has made little progress on reducing road deaths between 2001
and 2005. It has reached a seven percent reduction over this period,
compared to around 25 percent in Sweden and the Netherlands, and 35
percent in France.

So far we've had bogus claims that fly in the face of basic physics
and lies about the efficacy of road safety measures, plus a few straw
men "Ah, you're saying a so you must mean b"!

Lower speeds make the roads safer.

Prove me wrong, post your evidence without the hilarious (and
irrelevant to vulnerable road users) references to motorways.

A recent study of the Government's trial 20 mph zones provides
overwhelming evidence of their benefits.(5) Average speeds fell by 9.3
mph and casualties fell 60%. Child pedestrian casualties fell 70%.

5. Webster and mackie (1996) "A review of traffic calming schemes in
20 mph zones". TRL report 215

spindrift said:

The UK has made little progress on reducing road deaths between 2001
and 2005.

Which coincides nicely with the reign of the "cost recovery" system for
speed cameras.

Is it just a coincidence?

--
Matt B

Quoted message said:

spindrift (spindrift <[email hidden]>😉 gurgled happily, sounding
much like they were saying:

Quoted message said:

Eliminating all deaths from the roads is what Sweden are attempting
though, with astounding success:

I see that you are so conident in what you say, that you will only say
it in a ghetto where you hope the majority will support your inane
drooling.

In article <f3dcd4fd-635f-4fee-874c-63a8a83cb601
@e10g2000prf.googlegroups.com>, [email hidden] says...

Quoted message said:

The impact doesn't differ in a 30mph collision, as posted above.It's a
30mph collision, nothing else.

So if a driver is doing 23mph, and a runner runs headlong it the car at
7mph, the car driver should have slowed down because 30mph was too fast?
--
Carl Robson
Audio stream: http://www.bouncing-czechs.com:8000/samtest
Homepage: http://www.bouncing-czechs.com

spindrift said:

The UK has made little progress on reducing road deaths between 2001
and 2005.

Yet oddly enough, there's been a massive campaign on reducing speed
throughout that period. IME, it's worked. *AT REDUCING SPEED*. We now
have a generation of drivers whose answer following an accident will be
'but I was only doing 30'.

spindrift (spindrift <[email hidden]>😉 gurgled happily, sounding
much like they were saying:

Quoted message said:

Quoted message said:

Quoted message said:

> > To do this pupils need to become familiar and confident in their
> > application of the equation 1/2 mv2
> Finally, we get to a different - and this time correct - equation.

Quoted message said:

Quoted message said:

Quoted message said:

> Shame it assumes neither driver or pedestrian are paying any
> attention, and that therefore the collision is inevitable.

Quoted message said:

Quoted message said:

Quoted message said:

No such assumption is made.

Quoted message said:

Quoted message said:

Of course it is. It has to be, else the free-moving traffic speed is
irrelevant, in favour of the speed at impact, which will vary widely
from the same free-moving speed, dependent on driver attention.

Quoted message said:

The impact doesn't differ in a 30mph collision, as posted above.It's a
30mph collision, nothing else. The claim was made that one mph faster
will not make any difference, the understanding of physics that 16 year
olds are expected to display makes it clear this is nonsense.

<sigh>

So - two drivers, identical cars.

One doing 40mph.
One doing 30mph.

Two pedestrians run out into the road an identical distance in front of
them.

The 40mph driver is paying attention, brakes hard, hits the pedestrian
still doing 20mph.
The 30mph driver is in a world of his own, doesn't brake, and hits the
pedestrian at 30mph.

Yet in your view of things, the second impact is the less serious.

spindrift (spindrift <[email hidden]>😉 gurgled happily, sounding
much like they were saying:

Quoted message said:

And Sweden's roads are safer than the UK:

http://www.lboro.ac.uk/service/publicity/news-

releases/2007/81_road_safety.html

Quoted message said:

The UK has made little progress on reducing road deaths between 2001 and
2005. It has reached a seven percent reduction over this period,
compared to around 25 percent in Sweden and the Netherlands, and 35
percent in France.

Don't care what reductions have been made in the last few years. We're
reducing from a lower base, and they haven't quite caught up.

They will very soon, because our figures have stopped reducing and are
starting to go back up, solely because of the utterly muddle-headed
emphasis on "Speed Kills".

spindrift said:

(SteveH) said:

spindrift said:

On 22 Dec, 14:25, Adrian <[email hidden]> wrote:
> Adrian (Adrian <[email hidden]>😉 gurgled happily, sounding
> much like they were saying:

Quoted message said:

>> There was an RAC press release t'other day which quoted 94% of
>> accidents as being due to "driver error or 'injudicious action'"

Quoted message said:

> <notices embargo>
> Ooops. Please don't click on the link until Monday. Thanks.

Quoted message said:

For every 1% reduction in average traffic speed, crashes reduce by
an average of 5% (Taylor et al, TRL 421, 2000).

That's manipulating the statistics to make them say what you want
them
to say.

Do you *honestly* believe that driving at 29mph is safer than
driving at 30mph?
--
SteveH 'You're not a real petrolhead unless you've owned an Alfa
Romeo'www.italiancar.co.uk- Honda VFR800 - Hongdou GY200 - Alfa 75
TSpark Alfa 156 TSpark - B6 Passat 2.0TDI SE - COSOC KOTL
BOTAFOT #87 - BOTAFOF #18 - MRO # - UKRMSBC #7 - Apostle #2 - YTC #

Of course.

You understand basic physics:

Force (N) = mass (kg) × acceleration (m/s2)

Negated by the driver not crashing - maybe we should think about improving
standards? Maybe we could have expert drivers checking over the rest of us
to have a word with the dangerous ones - I think they used to be called
traffic police in the olden days.
--
MrBitsy

spindrift said:

(Steve Firth) said:

Brimstone said:

A woman who suffers a clinical fear of driving was yesterday facing
a ban after police caught her crawling down a motorway at - 10mph.

But spindrift and Crispin assure us that the slower one drives the
safer it is for everyone. The court must have it wrong considering a
driving ban for a safe driver like this.

She ought to go to the A27 and drive at 10mph to improve the
standard of road safety there.

Motorways, who cares, raise the limit, there's no cyclists or peds
there.

To put the dangerousness of speed into perspective, how many drivers
care about or would notice a 2mph reduction in their average speed?

Yet, averaged across the entire road network, a mere 2mph reduction in
average speeds would prevent more than 200 deaths and 3,500 serious
casualties a year.

In that case, maybe thge speed limit ought to be reduced by 50% - all
cancers would be eliminated at a stroke.
--
MrBitsy

spindrift said:

(SteveH) said:

spindrift said:

On 22 Dec, 15:14, [email hidden] (SteveH) wrote:
> spindrift <[email hidden]> wrote:
>>> Do you *honestly* believe that driving at 29mph is safer than
>>> driving at 30mph?
>> Of course.

Quoted message said:

>> You understand basic physics:

Quoted message said:

>> Force (N) = mass (kg) ? acceleration (m/s2)

Quoted message said:

> Go-on, then.

Quoted message said:

> If you're so clever, please tell us all what difference there will
> be in the acceleration rate of a person hit by a car doing 29mph
> rather than 30mph.

Quoted message said:

> Obviously, you've failed to take into account the error tolerances
> in all these calculations, which mean that a 1mph decrease in
> speed isn't actually a measurable difference.

Quoted message said:

Mass?

Quoted message said:

Use the formula.

The formula doesn't really help.

If you can find a way to show a significant difference using the
formula, please enlighten us.

However, the 1mph difference in the speed of the car could easily be
compensated for by the difference in speed of other objects hit.

--
SteveH 'You're not a real petrolhead unless you've owned an Alfa
Romeo'www.italiancar.co.uk- Honda VFR800 - Hongdou GY200 - Alfa 75
TSpark Alfa 156 TSpark - B6 Passat 2.0TDI SE - COSOC KOTL
BOTAFOT #87 - BOTAFOF #18 - MRO # - UKRMSBC #7 - Apostle #2 - YTC #-
Hide quoted text -

- Show quoted text -

Someone send out for a 16 year old school pupil:

Good idea - we could educate him about crossing the roads safely. We could
tell them not to have the Ipod on at insane levels, not yakking on the phone
while crossing. Maybe even teaching them to look while crossing?

Quoted message said:

You need to understand the science behind why the impact of a car
travelling at 40mph upon a pedestrian is about four times more likely
to kill the pedestrian than an impact with the same cart at 30mph.

How about telling the driver to look out for pedestrians? How about telling
the pedestrian to look out for cars?

Quoted message said:

To do this pupils need to become familiar and confident in their
application of the equation 1/2 mv2

Oh, I see we are still stuck on slowing cars down, even though speed
accounts for a low percentage of crashes. Oh well.

--
MrBitsy

spindrift said:

Speed is the single most important factor in road safety as the links
demonstrate. Reduce speed and accident rates plummet. Look at Hull.

I don't get it - all the threads and posts from the cyclists have all been
about dangerous driving. All of the examples have been due to poor
observation, lack of anticipation, poor planning and poor attitude.

Why are they now going on about speed?

--
MrBitsy

MrBitsy ("MrBitsy" <[email hidden]>😉 gurgled happily, sounding much like
they were saying:

Quoted message said:

Oh, I see we are still stuck on slowing cars down, even though speed
accounts for a low percentage of crashes. Oh well.

First, find your desired conclusion.
Next, manipulate the "evidence" to fit it, ignoring that which can't be
twisted sufficiently.

Adrian said:

MrBitsy ("MrBitsy" <[email hidden]>😉 gurgled happily, sounding much like
they were saying:

Quoted message said:

Oh, I see we are still stuck on slowing cars down, even though speed
accounts for a low percentage of crashes. Oh well.

First, find your desired conclusion.
Next, manipulate the "evidence" to fit it, ignoring that which can't be
twisted sufficiently.

You have been reading the police manual on giving evidence.