Safespeed spoilsports

[Paul Smith]

On Tue, 04 Mar 2003 15:05:17 +0000, "Just zis Guy, you know?" <[email protected]> wrote:

>>If available, then fine, but we have to be realistic about side effects. See:
>>http://www.safespeed.org.uk/tiger.html

>There is a widely held belief that drivers can be exoected to drive safely within the speed limit,
>and some are so rash as to suggest that having been required to demonstrate this at the time of
>passing their driving test it is not unreasonable to suppose that they may continue to be required
>to do so without significant detriment to road safety as they become more experienced. Funny, that.

Some may. Some will. Some won't. The "won't" group is far too large to ignore.

>>Your number 1) as interpreted by the authorities at the present time, is actually reducing
>>drivers' performances at 2 and 3.

>Oops! Argument by assertion again. Where's the proof? Oh, yes, you have acknowledged you don't have
>any of course. Ah, well.

Lack of proof does not stop it killing 3 each day.

>>Canadian research put 2/3rds of excess speed accidents as taking place within the speed limit.
>>It's reasonable to expect that the same applies on UK roads.

>And equally reasonable to suggest that this is not an argument for not enforcing speed limits.

It's an important component of one of the arguments, and goes towards reducing the benefit side of
the changes that cameras bring.

>>speed cameras cost lives

>But only when combined with dangerous drivers who are prepared to put speed above safety.
>Obviously.

But that's most of us for some of the time.
--
Paul Smith Scotland, UK http://www.safespeed.org.uk please remove "XYZ" to reply by email speed
cameras cost lives

 

[Paul Smith]

On 04 Mar 2003 15:12:47 +0000, Alan Braggins <[email protected]> wrote:

>> >Obvious conclusion: since speed limits have always existed and always been enforced to some
>> >extent, those drivers who allow themselves to become so focussed on speed as to allow it to take
>> >first place over safety are dangerous drivers.

>[...]

>> On the dangerous driver point, I expect about 60% of drivers are dangerous by your definition

>You claim 99% of drivers exceed the speed limit, most of them safely, but now you claim 60% of them
>are so focussed on sticking to the speed limit that they put it above safety. What's wrong with
>this picture?

Drivers run a sort of rolling priority task list. Speed limit adherence now takes priority over real
safety considerations for many drivers some of the time.

And

No speed is inherently dangerous. Speed only becomes dangerous if it is excessive for the
circumstances. The speed limit is about the roughest possible guide to the circumstances, and
exceeding the speed limit is NEVER in itself dangerous.
--
Paul Smith Scotland, UK http://www.safespeed.org.uk please remove "XYZ" to reply by email speed
cameras cost lives

 

[Paul Smith]

On Tue, 04 Mar 2003 15:07:30 +0000, "Just zis Guy, you know?" <[email protected]> wrote:

>>You can't base a road safety strategy on idealised drivers. You have to base it on what we've got.

>And allowing the current dangerous drivers to continue flagrantly disobeying whatever parts of the
>law they find momentarily inconvenient is not the very best approach.

That rather depends on your definitions.

If an approach makes the average driver more dangerous then it's a bad bad bad strategy. And that's
exactly what the strategy you're defending is doing.
--
Paul Smith Scotland, UK http://www.safespeed.org.uk please remove "XYZ" to reply by email speed
cameras cost lives

 

[Paul Smith]

On Tue, 04 Mar 2003 14:59:35 +0000, "Just zis Guy, you know?" <[email protected]> wrote:

>>All that dancing around, and you haven't even considered the specific question. Is this supposed
>>to be distraction?

>All that dancing around and you still haven't considered the laws of physics. Are you supposed to
>be credible?

Oh look. Oh dear. You've forgotten to answer the question again. Never mind. Here it is again:

"What evidence have you got that pre-incident KE is a big contributor to average crash energy?"
--
Paul Smith Scotland, UK http://www.safespeed.org.uk please remove "XYZ" to reply by email speed
cameras cost lives

 

[Colin Blackburn]

In article <[email protected]>,
[email protected] says...
> On Tue, 04 Mar 2003 14:59:35 +0000, "Just zis Guy, you know?" <[email protected]> wrote:
>
> >>All that dancing around, and you haven't even considered the specific question. Is this supposed
> >>to be distraction?
>
> >All that dancing around and you still haven't considered the laws of physics. Are you supposed to
> >be credible?
>
> Oh look. Oh dear. You've forgotten to answer the question again. Never mind. Here it is again:
>
> "What evidence have you got that pre-incident KE is a big contributor to average crash energy?"

It's the only contributor unless there are otherwise unseen external forces.

Colin

 

[Paul Smith]

On Tue, 4 Mar 2003 16:29:51 -0000, Colin Blackburn <[email protected]> wrote:

>> >>All that dancing around, and you haven't even considered the specific question. Is this
>> >>supposed to be distraction?

>> >All that dancing around and you still haven't considered the laws of physics. Are you supposed
>> >to be credible?

>> Oh look. Oh dear. You've forgotten to answer the question again. Never mind. Here it is again:

>> "What evidence have you got that pre-incident KE is a big contributor to average crash energy?"

>It's the only contributor unless there are otherwise unseen external forces.

Why do you guys bother with all these microscopic pedantic semantic points? I'm quite sure you
understand exactly what was meant in the context of the thread and the discussion.

You know very well that I'm talking about the proportion of KE given up in the crash to the
proportion of KE dissipated harmlessly by the drive in average circumstances.
--
Paul Smith Scotland, UK http://www.safespeed.org.uk please remove "XYZ" to reply by email speed
cameras cost lives

 

[Tony W]

"Paul Smith" <[email protected]> wrote in message
news:[email protected]...
>
> >Oops! Argument by assertion again. Where's the proof? Oh, yes, you have acknowledged you don't
> >have any of course. Ah, well.
>
> Lack of proof does not stop it killing 3 each day.

Now forgive me if I am wrong -- I find some of your arguments very difficult to follow. However:

1. I take it that the statement above suggests you believe that 3 people per day are losing
their lives as a direct result of the government's policy of using speed cameras to detect
speeding drivers.

2. A total of about 7 people per day die from RTAs on British roads (DfT figures and your
Tiger page).

So you could be claiming that over 40% of all deaths on the road are due to speed cameras.

Is this, indeed, what you are saying?

If you are right it is clearly an outrage. If we scrapped cameras tonight (easily done, a government
minister stands up and says no-one will be charged based on camera evidence forthwith) we would cut
death on the road by 40+%.

I agree -- proof would be nice but those figures are too horrifying to wait for proof. Turn the
cameras off and watch the accident figures tumble.

T

 

[Colin Blackburn]

In article <[email protected]>,
[email protected] says...

> Why do you guys bother with all these microscopic pedantic semantic points? I'm quite sure you
> understand exactly what was meant in the context of the thread and the discussion.
>
> You know very well that I'm talking about the proportion of KE given up in the crash to the
> proportion of KE dissipated harmlessly by the drive in average circumstances.

It isn't clear at all. Your original question was meaningless. Semantic points are quite important
as your 12mph demonstrated. Perhaps if you ask semantically correct questions you might get a little
bit more respect.

Colin

 

[Just Zis Guy]

On Tue, 4 Mar 2003 15:24:57 -0000, "Ambrose Nankivell" <[email protected]> wrote:

>I take issue with this. I (inadvertantly) broke the speed limit during my driving test and still
>managed to pass. Of course, it's more likely that the examiner didn't notice it

I would say it is certain that he didn't, as it's an immediate fail.

>What's more, Paul Smith does have a point that low speeds can cause frustration and that
>frustration can cause collisions. Mainly because impatient hotheads lose their temper and drive
>into things or get out and hit people.

Congestion causes low speeds that cause frustration. Trundling along at 30 in a queue of traffic is
no stress, in my experience anyway. Even whe I used to speed I didn't much care as long as the
traffic was moving - and anyone who seriously can't tolerate driving at 30 in a 30 limit needs to be
taken off the road ASAP.

One collateral benefit of slowing down is that it increases the effective capacity of the road,
of course.

But you mustn't misunderstand: I am not advocating reducing all speed limits (that's one of Smith's
straw men), merely arguing with Smith's tired and discredited assertion that speed enforcement costs
lives while speeding doesn't. My view is that one shuld drive at a speed which is safe and legal.
This is not normally considered a controversial view.

And this entire thread was started by his 12mph page, which was a bizarre piece of misinformation,
and by Smith's oft-repeated claim that "cameras cost lives," for which he has no proof, and nor has
he provided any crdible evidence of having looked for any (such as plots of fatality rates against
other possible factors, a basic part of testing any hypothesis).

>However, I imagine that in most places the speed limits are sufficiently high to avoid this
>happening so this effect can be safely discounted. I'd be interested to know if this is the
>rationale behind Paul Smith's claim that driver ability increases with speed.

That is a foolish claim, and I think he knows it. A driver who is genuinely incapable of
concentrating sufficiently to drive within the speed limit is either too tired or too stupid to be
driving at all. One of the most fatuous reasons ever advanced for speeding was "to keep you awake" -
I've done that, driving along at 135mph in order to keep awake after a 120-hour week, and safe is
absolutely the last word I'd use to describe such behaviour.

>Furthermore, I'm not a hugely experienced driver, but I find that at speeds well within the speed
>limit, my senses are well saturated with inputs and potential hazards, perhaps with the exception
>of empty motorways.

Ah, there's a thing. I find that at my normal speeds - speeds close to but within the limit - I have
a far better appreciation of the road environment than I used to have when I drove faster. As an
example, there is a stretch of road where I regularly used to thrash through at 60, regarding the 40
limit as pointless and arbitrary. It was only when I started driving at 40 that I noticed a school
tucked back about 50 yards from the road.

I maintain that if a learner can reasonably be expected to drive safely and obey the speed limit, so
can an experienced driver.

Guy
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[Just Zis Guy]

On Tue, 04 Mar 2003 16:26:43 +0000, Paul Smith <[email protected]> wrote:

>Oh look. Oh dear. You've forgotten to answer the question again. Never mind. Here it is again:
>"What evidence have you got that pre-incident KE is a big contributor to average crash energy?"

Oh look. Oh dear. You've forgotten to read the answer again. Never mind. Here it is again:

First, the crash energy is formed of a component of pre-incident KE. Therefore, the pre-incident KE
contributes in the same way that a cow contributes to a steak. This much is obvious.

Second, if the pre-incident KE is, say, for the sake of illustration, 30% lower by virtue of the car
going at 70mph instead of 80mph THE CRASH MAY NOT HAPPEN AT ALL. This much is also obvious.

Work it any way you want. Start at the crash and work back, the car at 70mph can brake at the same
time but less sharply, reducing the chances of loss of control or being shunted by the tailgater
behind; the driver can brake at the same time with the same force and avoid the accident
altogether; or the driver has a brief extra margin for error can still reduce to the same speed at
the same point.

Guy
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[Paul Smith]

On Tue, 4 Mar 2003 17:10:31 -0000, "Tony W" <[email protected]> wrote:

>> Lack of proof does not stop it killing 3 each day.

>Now forgive me if I am wrong -- I find some of your arguments very difficult to follow. However:

>1. I take it that the statement above suggests you believe that 3 people per day are losing
> their lives as a direct result of the government's policy of using speed cameras to detect
> speeding drivers.

And all that has come with it. Yes. (including loss of traffic police, "speed kills" as a primary
road safety message, loss of focus and investment in other, better road safety strategies, etc)

>2. A total of about 7 people per day die from RTAs on British roads (DfT figures and your Tiger
> page).

It's about 10 who die daily in 7 accidents.

>So you could be claiming that over 40% of all deaths on the road are due to speed cameras.

A bit under 30%.

>Is this, indeed, what you are saying?

Yes.

>If you are right it is clearly an outrage. If we scrapped cameras tonight (easily done, a
>government minister stands up and says no-one will be charged based on camera evidence forthwith)
>we would cut death on the road by 40+%.

No chance. But we could immediately return to a 5% per annum improvement in fatality figures.

>I agree -- proof would be nice but those figures are too horrifying to wait for proof. Turn the
>cameras off and watch the accident figures tumble.

It doesn't work quite like that. The system has a great deal of inertia.
--
Paul Smith Scotland, UK http://www.safespeed.org.uk please remove "XYZ" to reply by email speed
cameras cost lives

 

[Dr]

"Paul Smith" <[email protected]> wrote in

>
> The point is that from the start to the finish of an average incident only about 2% of the KE ends
> up in the crash. Most of the rest is shed by driver response (braking etc).

No. You cannot assume that a crash is a single severe frontal impact. A crash can involve several
small impacts, metal grinding on road/other metal, destroying a hedge, cutting a furrow in a field
etc, etc. All of these damage the car but may keep severe acceleration off the occupants. It is low
acceleration only that allows people to survive crashes after travelling at speed; braking is not a
pre-requisite and very naive of you to consider it as the only possible reason.

David Roberts

 

[Just Zis Guy]

On Tue, 04 Mar 2003 17:06:54 +0000, Paul Smith <[email protected]> wrote:

>Why do you guys bother with all these microscopic pedantic semantic points? I'm quite sure you
>understand exactly what was meant in the context of the thread and the discussion.

Yes, unfortunately yu apparently don't.

>You know very well that I'm talking about the proportion of KE given up in the crash to the
>proportion of KE dissipated harmlessly by the drive in average circumstances.

What part of this are you having trouble understanding, because to me it seems very simple but I
have three Maths A levels, two physics A levels and an engineering degree, so perhaps I need to make
it simpler.

* Car A travels at 80mph
* Car B travels at 70mph
* Kinetic energy varies with speed squared, so car A has 30% more kinetic energy than car B.
* An incident occurs and car A crashes at 20mph

All other factors remain constant.

So, if car B dissipates the same amount of KE, it stops short of the incident. The 95% of car A's KE
which it sheds in braking is more than the total which car B started with.

Or you can use classical mechanics. Let's assume that driving at 70mph makes your reactions half as
fast as driving at 80 - a much bigger margin that I would credit, but let's allow it for the sake
of argument.

A hazard arises in front of car A. Allow 0.5s reaction time and posit an impact speed of 20mph.
That's a total distance of a shade over 94m
- few of us could do better, I think. Car A, then, waits an extra .5s before applying the brakes
with the same force and... stops nearly 6m short of car B.

Of course we could ignore the time at which the cars aply the brakes and *just* look at the energy
at impact - but that would be tantamount to saying that if two cars hit an object at the same speed,
they hit it at the same speed. Accurate enough, but not particularly instructive.

Guy
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[Just Zis Guy]

On Tue, 04 Mar 2003 16:19:26 +0000, Paul Smith <[email protected]> wrote:

>>There is a widely held belief that drivers can be exoected to drive safely within the speed
>>limit, and some are so rash as to suggest that having been required to demonstrate this at the
>>time of passing their driving test it is not unreasonable to suppose that they may continue to be
>>required to do so without significant detriment to road safety as they become more experienced.
>>Funny, that.

>Some may. Some will. Some won't. The "won't" group is far too large to ignore.

But you must accept that, on the evidence that they were able to manage it while they were still
unqualified and inexperienced, it is very definitely "won't" rather than "can't." And for those who
won't obey the law we have courts.

>>Oops! Argument by assertion again. Where's the proof? Oh, yes, you have acknowledged you don't
>>have any of course. Ah, well.

>Lack of proof does not stop it killing 3 each day.

Oops! Argument by assertion again. Lack of proof means precisely that: you can't prove that it has
ever killed a single person

>>And equally reasonable to suggest that this is not an argument for not enforcing speed limits.

>It's an important component of one of the arguments, and goes towards reducing the benefit side of
>the changes that cameras bring.

So what? So cameras only bring X amount of benefit instead of 2X or
3X. Big fat hairy deal. Speeding, by contrast, brings absolutely no benefit to safety.

>>>speed cameras cost lives
>>But only when combined with dangerous drivers who are prepared to put speed above safety.
>>Obviously.
>But that's most of us for some of the time.

By "us" do you include yourself? Are you prepared to put speed above safety? I came across three
people today who put /their/ speed above /my/ safety - is that OK? How about the time last week when
I was run off the road by someone whose speed was more important than my safety. Was that
acceptable?

Guy
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[Just Zis Guy]

On Tue, 04 Mar 2003 16:22:35 +0000, Paul Smith <[email protected]> wrote:

>>>You can't base a road safety strategy on idealised drivers. You have to base it on what
>>>we've got.

>>And allowing the current dangerous drivers to continue flagrantly disobeying whatever parts of the
>>law they find momentarily inconvenient is not the very best approach.

>That rather depends on your definitions.

Not as such, no. Remember, even learners are required to demonstrate that they can drive both safely
and legally at the same time.

>If an approach makes the average driver more dangerous then it's a bad bad bad strategy. And that's
>exactly what the strategy you're defending is doing.

Oops! Argument by assertion again. You have no proof, as ou ahve repeatedly admitted. I, on the
other hand, have conclusive proof that speeding is illegal, that even the newest drivers are
required to demonstrate that they can drive safely within the speed limit, and that the probability
of fatality if an accident does happen rises with speed. All these are facts, not unsupported
assertions.

You appear to be attempting to justify those drivers who are so determined to speed that they would
rather sacrifice safety than slow down. These are dangerous drivers. There is no other possible
conclusion.

Guy
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[Paul Smith]

On Tue, 04 Mar 2003 21:25:32 +0000, "Just zis Guy, you know?" <[email protected]> wrote:

>>Why do you guys bother with all these microscopic pedantic semantic points? I'm quite sure you
>>understand exactly what was meant in the context of the thread and the discussion.

>Yes, unfortunately yu apparently don't.

>>You know very well that I'm talking about the proportion of KE given up in the crash to the
>>proportion of KE dissipated harmlessly by the drive in average circumstances.

>What part of this are you having trouble understanding, because to me it seems very simple but I
>have three Maths A levels, two physics A levels and an engineering degree, so perhaps I need to
>make it simpler.

>* Car A travels at 80mph
>* Car B travels at 70mph
>* Kinetic energy varies with speed squared, so car A has 30% more kinetic energy than car B.
>* An incident occurs and car A crashes at 20mph
>
>All other factors remain constant.

And if all other factors are constant, what accounts for the difference in speed?

You do live in the real world don't you?
--
Paul Smith Scotland, UK http://www.safespeed.org.uk please remove "XYZ" to reply by email speed
cameras cost lives

 

[Paul Smith]

On Tue, 4 Mar 2003 20:33:37 +0000, Michael MacClancy <[email protected]> wrote:

>In message <[email protected]>, Paul Smith
><[email protected]> writes

>>"What evidence have you got that pre-incident KE is a big contributor to average crash energy?"

>The only source of "average crash energy" is "pre-incident KE". It's not only a big contributor,
>it's the only contributor.

True, but you know what I meant.
--
Paul Smith Scotland, UK http://www.safespeed.org.uk please remove "XYZ" to reply by email speed
cameras cost lives

 

[Tony W]

"Paul Smith" <[email protected]> wrote in message
news:[email protected]...

> >If you are right it is clearly an outrage. If we scrapped cameras
tonight
> >(easily done, a government minister stands up and says no-one will be charged based on camera
> >evidence forthwith) we would cut death on the
road
> >by 40+%.
>
> No chance. But we could immediately return to a 5% per annum improvement in fatality figures.
>
> >I agree -- proof would be nice but those figures are too horrifying to
wait
> >for proof. Turn the cameras off and watch the accident figures tumble.
>
> It doesn't work quite like that. The system has a great deal of inertia.

OK -- this is interesting. Can you clarify a couple of points, please?

I take it you are estimating the 3 deaths per day by extrapolating the trend line from 1992 on to
2003. i.e. if we had continued the with the same rate of improvement pre 1992 to today we would be
killing 7 per day on our roads rather than 10 (my apologies for getting the numbers wrong before, I
was working from memory rather than checking).

So these deaths cannot be directly related to cameras, per se -- but to the 'lost opportunity' to
continue the pre 1992 trend lines that cameras brought about?

T

 

[Just Zis Guy]

On Tue, 4 Mar 2003 20:58:28 -0000, "DR" <[email protected]> wrote:

> braking is not a pre-requisite and very naive of you to consider it as the only possible reason.

It's OK, the formula he used to derive the impact speed was misapplied anyway - I don't think a
little thing like that will sway him :-D

Guy
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[Paul Smith]

On Tue, 4 Mar 2003 20:58:28 -0000, "DR" <[email protected]> wrote:

>> The point is that from the start to the finish of an average incident only about 2% of the KE
>> ends up in the crash. Most of the rest is shed by driver response (braking etc).

>No. You cannot assume that a crash is a single severe frontal impact. A crash can involve several
>small impacts, metal grinding on road/other metal, destroying a hedge, cutting a furrow in a field
>etc, etc. All of these damage the car but may keep severe acceleration off the occupants. It is low
>acceleration only that allows people to survive crashes after travelling at speed; braking is not a
>pre-requisite and very naive of you to consider it as the only possible reason.

I'm not, and I have been considering those other factors. I'm reworking the 12mph page, and those
sorts of factors are already included.

I've been looking at various statistics, hoping to make deductions about the various places that
energy might be dissipated, on average.

At present there are too many assumptions, but the average KE remaining in the average injury crash
may well turn out to be under .5% of the average KE in pre incident conditions on A roads.

It's nothing if not remarkable, and I wonder why no one else appears to have taken this approach.

Even without trying to analyse accidents, it seems worthy to consider how much KE may be shed safely
by drivers braking each day and mentally compare it with the amount of KE expended in accidents.
It's probably millions to 1. Why do we think KE kills again? And what if those drivers hadn't
braked? Where would the KE have gone then?
--
Paul Smith Scotland, UK http://www.safespeed.org.uk please remove "XYZ" to reply by email speed
cameras cost lives