"Experienced driver pumping the brakes" is what I was referring to. That's
why I said it was "iffy" for the average driver. In no way did I imply that
locking up the brakes is generally the most effective method of braking; in
fact, maintaining each braked wheel at the very verge of lock-up is the most
effective method in almost every circumstance. "Pumping" (or automatic ABS
switching) is one method to achieve this.
While NOT locking up the wheels is correctly preferred in most (almost all)
conditions, as you noted, there ARE exceptions: "Squeegee effect", in
standing water. "Snowplow" effect, in loose snow.
ABS is unable to make this kind of determination; hence the tale of the
fellow who slid his BMW completely across the icy parking lot. One suspects
he was entering at too high of a speed in this case; but one also suspects
that this was because of his habitual dependency on his ABS braking. So
there are two sides to the question.
What frightens me are the people driving enormous modern luxury cars and
SUVs that habitually race up to stoplights at high speed, relying on their
equally enormous multi-piston disc brakes to stop them at the last possible
moment (usually with their bumper 5 feet into the crosswalk). Since they are
already using 95% of their maximum deceleration, it would only take the
slightest mischance to cause an accident; for instance, half a pint of
spilled antifreeze in the lane, and a little old lady stepping off the curb
unexpectedly. Apparently these people have never experienced even a partial
brake failure. Or perhaps they are just convinced that their 17-airbag
safety cocoon wil protect them no matter what (too bad about that LOL).
--
Max Heim
'66 MGB GHN3L76149
If you're near Mountain View, CA,
it's the primer red one with chrome wires
on 10/18/06 1:07 PM, Charles & Peggy Robinson at ccrobins@ktc.com wrote:
> Well, I don't think that's exactly what Paul said. I believe he
> added the caveat of an experience driver pumping the brakes. Well
> that's what ABS does FOR the driver. Also, I disagree that locking the
> wheel up provides the most effective braking. My experience and lots of
> studies say otherwise. Just think; if locking them up was most
> effective why pump the brakes?
>
> Cheers,
>
> CR
>
>
> Max Heim wrote:
>> Yes, but as Paul points out, in certain wet conditions, or on snow or ice,
>> locking up can be the most effective method of braking, provided you can
>> maintain directional stability. But that is a big "if", for the average
>> driver.
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