Velvet wrote:

Q. Does ABS reduce stopping distances?

A. Yes, in braking situations where the wheels on a non-ABS equipped
vehicle would lock up, ABS will generally provide shorter controlled
stopping distance. The amount of improvement in stopping distance
depends on many factors, including the road surface, severity of
braking, initial vehicle speed, etc. On some surfaces, such as gravel
roads, braking distances can be longer, but you will still have the
control benefits of ABS. The important capability of ABS is control.
ABS provides improved vehicle steerability and stability when braking.

In other words, yes and no, but for practical purposes no, unless the wheels
would be locking up. Which they generally don't. And, as stated, "the
important capability of ABS is control."

--
Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

Just zis Guy, you know? wrote:

Velvet wrote:


Q. Does ABS reduce stopping distances?


A. Yes, in braking situations where the wheels on a non-ABS equipped
vehicle would lock up, ABS will generally provide shorter controlled
stopping distance. The amount of improvement in stopping distance
depends on many factors, including the road surface, severity of
braking, initial vehicle speed, etc. On some surfaces, such as gravel
roads, braking distances can be longer, but you will still have the
control benefits of ABS. The important capability of ABS is control.
ABS provides improved vehicle steerability and stability when braking.


In other words, yes and no, but for practical purposes no, unless the wheels
would be locking up. Which they generally don't. And, as stated, "the
important capability of ABS is control."


Interesting that you made no comment on the second snippet I posted,
which came from the designers of the ABS system themselves...

Given the amount of people who know skidding = longer stopping
distances, they almost certainly will attempt to err on the side of not
inducing a skid, thus they will be braking less effectively than if they
had ABS and knew it would stop the skid.

I also uncovered some very interesting studies which showed that brkae
assist (something different to ABS) stops the problem of a driver
lifting the braking force to start the foetal curl reaction - again,
tends to indicate that in amny situations the car will not be travelling
at the point of skidding, and that again, would would take longer to
stop than if it *is* on the point, and has ABS, and they are, therefore,
engaged. Brake assist, in case you're unfamiliar, is where the car
takes over and KEEPS the pressure on the brakes even if the driver lifts
it off. Obviously, tends to be used in conjunction with ABS. WHich
tends to suggest that ABS is misused by quite a few people who've never
tried it to feel what it is like through a pedal, or who default (quite
dangerously) to pumping the brakes even though they have an ABS equipped
car.

The solution to the dirver confusion would seem to be to either fit all
cars or no cars with ABS, thus in the instant where you have to decide
if you tromp or pump, you get it right, and given the benefits of ABS on
mixed-surfaces/low grip etc, I think ABS on all is the way to go.

And it still stops me in a shorter distance on dry roads. And I'm sure
I'm not the only one who'll err the less-pressure side of the line in
that situation to avoid the skid. Which means that ABS does stop you
quicker, in that situation. If you've got excellent braking control
then granted it's probably not going to make a lot of difference, but
lets face it, how many people have - should we be devoting our sunday
afternoons to go do emergency stops repeatedly on the public roads, once
a month, just so we can claim we can stop in the same distance with a
non-abs car as we can with an abs one?

I think not.

--


Velvet

Velvet wrote:

Interesting that you made no comment on the second snippet I posted,
which came from the designers of the ABS system themselves...
Given the amount of people who know skidding = longer stopping
distances, they almost certainly will attempt to err on the side of
not inducing a skid, thus they will be braking less effectively than
if they had ABS and knew it would stop the skid.

So few people get anywhere near the limiting braking performance of their
cars that I don't see that being much of an issue.

But like I say, if you want to carry on pushing the fiction that ABS is
there to make you stop quicker, think carefully about the possible
repercussions. It is a commonly held view, and it is responsible for risk
compensation behaviour which means that overall what advantage there is is
consumed as a performance benefit. As ever.

The solution to the dirver confusion would seem to be to either fit
all cars or no cars with ABS, thus in the instant where you have to
decide if you tromp or pump, you get it right, and given the benefits
of ABS on mixed-surfaces/low grip etc, I think ABS on all is the way
to go.

I think the EU is already onto that one.

And it still stops me in a shorter distance on dry roads.

Lucky you. Not having managed to get the ABS to even cut in on a dry road,
it doesn't do that for me.

--
Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

Just zis Guy, you know? wrote:

Velvet wrote:


Interesting that you made no comment on the second snippet I posted,
which came from the designers of the ABS system themselves...
Given the amount of people who know skidding = longer stopping
distances, they almost certainly will attempt to err on the side of
not inducing a skid, thus they will be braking less effectively than
if they had ABS and knew it would stop the skid.


So few people get anywhere near the limiting braking performance of their
cars that I don't see that being much of an issue.

But like I say, if you want to carry on pushing the fiction that ABS is
there to make you stop quicker, think carefully about the possible
repercussions. It is a commonly held view, and it is responsible for risk
compensation behaviour which means that overall what advantage there is is
consumed as a performance benefit. As ever.

I'm not pushing the fiction. You very carefully say 'its not there to
stop you quicker', I say in a given circumstance it will. We aren't
talking about the same thing, and I know it, and I think you know it too.

I'm not generalising, I'm pointing out a specific instance where having
ABS fitted - WHETHER THEY CUT IN OR NOT - will lead to stopping faster.
That is NOT pushing the fiction that ABS is there to make you stop faster.

Whether I compensate for that or not I can't say for sure - whereas you
seem to know so much about my driving that you can say catagorically
that I would. Odd that, really.

I dislike generalisations, and the 'ABS wont make you stop faster' is
just such a generalisation. It's become abundantly clear you're only
interested in the generalisation though.

I'll continue to prefer a car with ABS. Cos at the end of the day, at
some point in the estimated 35,000 miles I'll do over the coming year
(all things being equal) I *might* just be in a situation where either
they, or my enthusiasm for applying brakes without worrying about the
potential for a skid, will stop me in time when a car without would not.

*I'd* rather have something that increases the safety. If you don't mind.



The solution to the dirver confusion would seem to be to either fit
all cars or no cars with ABS, thus in the instant where you have to
decide if you tromp or pump, you get it right, and given the benefits
of ABS on mixed-surfaces/low grip etc, I think ABS on all is the way
to go.


I think the EU is already onto that one.


And it still stops me in a shorter distance on dry roads.


Lucky you. Not having managed to get the ABS to even cut in on a dry road,
it doesn't do that for me.


I've explained it doesn't HAVE to cut in on a dry road to reduce my
stopping distance, please see above and try to understand, I'm
explaining it as clearly as I can!


--


Velvet

Velvet wrote:

You very carefully say 'its not there to
stop you quicker', I say in a given circumstance it will. We aren't
talking about the same thing, and I know it, and I think you know it
too.

Possibly. I guess it's like the difference between "my helmet saved my
life" and "helmets save lives".

I dislike generalisations, and the 'ABS wont make you stop faster' is
just such a generalisation. It's become abundantly clear you're only
interested in the generalisation though.

I am indeed. The generalisation is what people will be thinking about as
they consume the safety benefit of ABS as a performance benefit. "I can
stop quicker thanks to ABS" therefore "I don't need to leave as much space".

I'll continue to prefer a car with ABS. [...]
*I'd* rather have something that increases the safety. If you don't
mind.

I am extremely unlikely ever to buy another car without ABS. I do not
dispute that it improves my safety should an emergency situation is reached,
by allowing control under braking and by compensating for my indifferent
braking technique. Overall, the evidence is that I will subconsciously undo
that safety benefit by worse driving, but that's risk compensation for you.

Lucky you. Not having managed to get the ABS to even cut in on a
dry road, it doesn't do that for me.

I've explained it doesn't HAVE to cut in on a dry road to reduce my
stopping distance, please see above and try to understand, I'm
explaining it as clearly as I can!

Yes, you've given an example of compensating behaviour. I don't dispute it.
But it hasn't changed the capabiliites of the car, which is my point.

Like the two old women exchanging words across the Shambles, we are arguing
from different premises.

--
Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

On Tue, 22 Jun 2004 11:55:07 +0100, "Just zis Guy, you know?"
wrote (more or less):

Velvet wrote:

You very carefully say 'its not there to
stop you quicker', I say in a given circumstance it will. We aren't
talking about the same thing, and I know it, and I think you know it
too.

Possibly. I guess it's like the difference between "my helmet saved my
life" and "helmets save lives".

I dislike generalisations, and the 'ABS wont make you stop faster' is
just such a generalisation. It's become abundantly clear you're only
interested in the generalisation though.

I am indeed. The generalisation is what people will be thinking about as
they consume the safety benefit of ABS as a performance benefit. "I can
stop quicker thanks to ABS" therefore "I don't need to leave as much space".
....
Like the two old women exchanging words across the Shambles, we are arguing
from different premises.
....

But Velvet's generalisation is more generaly true that your
generalisation, Guy.

You say Guy 'ABS is not there to shorten braking distances'. In fact
it does.

/Generally/ by a lot for unskilled brakers who will lock up the tyres.
(This was its original selling point. Unlocked wheels stop faster than
locked wheels).

/Generally/ by a bit for highly skilled brakers who can keep their
wheels from locking up, but only by using the lowest common
non-locking braking force on all four wheels

It also will /generally/ extend braking distances on loose surfaces
where locked wheels may create wedges in front of the themselves.

Your main objection seems to be that if folk think of ABS as a way of
braking faster, they'll consume this as a performance benefit.

This is likely true.

But saying ABS does not provide braking distance benefits (in general)
is untrue, even if I agree with you that we should be trying to stop
drivers consuming all safety benefits in the form of increased
performance.


--
Cheers,
Euan
Gawnsoft: http://www.gawnsoft.co.sr
Symbian/Epoc wiki: http://html.dnsalias.net:1122
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On Tue, 22 Jun 2004 17:39:18 +0100, Gawnsoft
wrote in message
:

But Velvet's generalisation is more generaly true that your
generalisation, Guy.

You say Guy 'ABS is not there to shorten braking distances'. In fact
it does.

Actually we are both right. That's not what it's for, but as a side
effect it can.

Your main objection seems to be that if folk think of ABS as a way of
braking faster, they'll consume this as a performance benefit.

They do indeed. It's like telling people a helmet will save their
life. It could conceivably happen, but that's not what it's designed
for and you shouldn't rely on it.

Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk

88% of helmet statistics are made up, 65% of them at Washington University

In message , "Just zis Guy, you know?"
writes
It is a commonly held view, and it is responsible for risk
compensation behaviour which means that overall what advantage there is
is consumed as a performance benefit. As ever.
This is like saying "replace the airbag with a six inch steel spike."
the driver will be much more careful, though I not sure any safer.
--
Clive

On Wed, 23 Jun 2004 15:31:47 +0100, Clive
wrote (more or less):

In message , "Just zis Guy, you know?"
writes
It is a commonly held view, and it is responsible for risk
compensation behaviour which means that overall what advantage there is
is consumed as a performance benefit. As ever.
This is like saying "replace the airbag with a six inch steel spike."
the driver will be much more careful, though I not sure any safer.

Depend swhat you mean by 'safer'.

'Less likely to be involved in a fatality' is different from 'less
likely to die him/herself'
--
Cheers,
Euan
Gawnsoft: http://www.gawnsoft.co.sr
Symbian/Epoc wiki: http://html.dnsalias.net:1122
Smalltalk links (harvested from comp.lang.smalltalk) http://html.dnsalias.net/gawnsoft/smalltalk

Clive wrote:

It is a commonly held view, and it is responsible for risk
compensation behaviour which means that overall what advantage there
is is consumed as a performance benefit. As ever.

This is like saying "replace the airbag with a six inch steel spike."
the driver will be much more careful, though I not sure any safer.

It's more like telling someone a helmet will Save Their Life [tm]

--
Guy
--
May contain traces of irony. Contents liable to settle after posting.
http://www.chapmancentral.co.uk