Everything we know about traffic-calming is wrong - Page 5

taywood <taywood@deadspam.com> wrote:
> Marc Brett wrote:
>> Everything we know about traffic-calming is wrong
>
> But is there a proven alternative to speed bumps, round or
> flat tops, and the raised platforms our Council are
> fitting at each minor road junction?

Yes. No speed humps or platforms.

--
http://www.speedlimit.org.uk
"Banning things others enjoy is the only pleasure some people get."

On Mon, 21 Jun 2004 22:25:28 +0100, "PeterE"
<peter@xyz_ringtail.fsnet.co.uk> wrote in message
<cb7jo8$ik$1@news8.svr.pol.co.uk>:

>> But is there a proven alternative to speed bumps, round
>> or flat tops, and the raised platforms our Council are
>> fitting at each minor road junction?

>Yes. No speed humps or platforms.

Or paint or signage.

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

On Mon, 21 Jun 2004 21:10:50 GMT, Velvet <velvet@not.a.valid.domain>
wrote in message <u9IBc.2210$pC2.19786878@news-text.cableinet.net>:

>Look, I've explained how ABS could stop ME quicker, you'll
>note I've not said it'll stop EVERYONE quicker. Perhaps you
>overlooked that subtle point?

Nope, not overlooked. You really do need to read Risk: John
Adams says it far better than I can.

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

All snipped, since replying to myself rarely makes sense.

I quote from a few websites...

Q. Does ABS reduce stopping distances?

R. 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.

(from the General Motors website gm.com, who, presumably,
should understand this concept of ABS)

Rotational-speed sensors continuously monitor each wheel. As
soon as incipient lock-up is detected at a wheel, ABS
temporarily reduces the braking pressureat the wheel in
question to such a degree that lock-up is prevented.

ABS repeats this monitoring and control cycle in rapid
succession for each wheel. This form of electronic wheel-
slip control ensures optimum braking distances while at the
same time maintaining full steerability and stability.

“ABS substantially improves driving stability and usually
shortens the brake path as well,” says Wolfgang Drees,
member of the management board at Robert Bosch GmbH and head
of its Chassis Systems division.

(From bosch.de, who designed ABS)

The only data I can find (and I can find no actual study
data on any of this) indicates that ABS when incorrectly
used leads to longer stopping distances (user pumps brakes
when ABS is fitted - bad!), and that ABS on loose surfaces
can lead to longer stopping distances.

However, everything I'm reading says that in most situations
because it can keep the car on the limit of skidding more
accurately than a driver (who physically can't pump the
brakes 15 times a second, for example) it will perform at
least as well, and even on dry roads where the friction
coefficient is greatest, normally slightly better. On wetter
roads, or differing surfaces, it greatly outperforms the
driver with no ABS.

I'm now bored of this and have realised that I've spent a
good half an hour looking stuff up to find out if what I've
believed is correct (which it seems to be) so now I'm off to
get on my bike and burn some more calories, though of
course, I'll be making sure to find out if it's got ABS on
before I decide how I should brake in an emergency, of
course ;-)

--

Velvet

"Just zis Guy, you know?" <outlook.bugs@microsoft.com> wrote in message
news:buked05pa8hqm77duf1pcvdkhk9t98rjij@4ax.com...
> On Mon, 21 Jun 2004 22:25:28 +0100, "PeterE"
> <peter@xyz_ringtail.fsnet.co.uk> wrote in message
> <cb7jo8$ik$1@news8.svr.pol.co.uk>:
>
> >> But is there a proven alternative to speed bumps, round
> >> or flat tops, and the raised platforms our Council are
> >> fitting at each minor road junction?
>
> >Yes. No speed humps or platforms.
>
> Or paint or signage.
>

We can dream :-)

Tony Raven wrote:
> AndyMorris wrote:
>>
>> Dope messes with your perception of speed, smoke enough
>> and try to drive and the cops will pull you over for
>> doing 10 mph on a clear road.
>
> Sounds like that might have been personal experience
> there ;-)
>
> Tony

I wasn't driving, but I was giving the driver some stick for
doing 25 round Huddersfield ring road.

--
Andy Morris

AndyAtJinkasDotFreeserve.Co.UK

Love this:
Put an end to Outlook Express's messy quotes
http://home.in.tum.de/~jain/software/oe-quotefix/

On 21/6/04 6:57 pm, in article
skFBc.1998$K81.18184246@news-text.cableinet.net, "Velvet"
<velvet@not.a.valid.domain> wrote:

> I've braked on ice with ABS - it was interesting and I'm
> glad I did it gently. Stopped car from sliding but took a
> VERY long time to stop the car. On the other hand, braked
> once on snow and had to do a very abs-like recovery of it
> to stop in time (downhill on snow toward T junction).

Snow and ice are like that. Very slippery, ABS or not.

I used to live in Norway and even with winter tyres would
still take a long time to stop. In some situations it is so
slippery ABS won't help. In general though I do a brake test
and see how long it takes to stop. Despite being a very
cautious driver (I'm the one who enjoys the open road ahead
of them..) I almost always ended up slowing down further.

Having proper winter tyres on the bike is also a lot of fun.
Normal tyres will just slide on black ice.. studded tyres
are absolutely fantastic. I've towed the trailer up a 1 in
10 hill on sheet ice. Kind of mind blowing when you can
hardly walk up the hill.

..d

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

On 21/6/04 10:23 pm, in article 2jp20jF13iilkU1@uni-berlin.de, "taywood"
<taywood@deadspam.com> wrote:

> But is there a proven alternative to speed bumps, round or
> flat tops, and the raised platforms our Council are
> fitting at each minor road junction?

Impound speeding cars for a day per % over the speed limit
(after some arbitrary cutoff like 5mph). That'll soon
prevent speeding. Combine that with concealed cameras.

Priority to the left in residential streets (as per the
continent).

Both these two would make the roads much safer in
built up areas

(and scrap the speed bumps).

..d

outlook.bugs@microsoft.com schreef ...

> It is simplistic, of course; the reality is that given
> perfect braking technique a driver can stop at least as
> quickly in a non-ABS car; ABS makes no difference to the
> grip of the tyres or the power of the brakes.

A really
> expert driver can theoretically stop shorter in a non-ABS
> car, because ABS senses wheel slip, while a really expert
> driver won't allow that to happen. In practice few drivers
> have perfect braking technique, but as previously posted,
> on a dry road it is close to impossible to get the ABS
> even to cut in on my car - it grips too well. So, ABS
> prevents some skids due to poor braking technique, and
> allows steering while braking with less risk of loss of
> control, but it doesn't really improve the braking
> performance of the car.
>
> It's also a mistake to rely on it in ice or on gravel. If
> all wheels lock, the ABS thinks you've stopped and cuts
> out. Don't try this at home!

Yes, I know that one (in a demonstration situation). Funny
:-/

> So, it's important not to think (or to allow people to
> think) "ABS stops you quicker", because (a) technically it
> doesn't and (b) relying on that for safety margin is a
> Very Bad Idea.

Agreed.

--
Regards, Marten

On Tue, 22 Jun 2004 09:21:13 +0100, "Just zis Guy, you know?"
<outlook.bugs@microsoft.com> wrote (more or less):

>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.

You don't drive in the wet much, do you Guy?

>And, as stated, "the important capability of ABS is
>control."

--
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

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

Gawnsoft wrote:

>> In other words, yes and no, but for practical purposes
>> no, unless the wheels would be locking up. Which they
>> generally don't.

> You don't drive in the wet much, do you Guy?

I don't drive much at all these days. And I don't generally
drive close enough to the car in front that I need to brake
sharply in the wet or in the dry.

>> 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:
>
>
>>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