>> A competent authority has assessed that ABS brakes 
>> INCREASE stopping
>> distances on gravel (metal) surfaces by typically 20+ 
>> percent.

> Is that a surprise?

No.
I wrote that mainly for my son, who has recently purchased a 
car with ABS and was telling me how well it stopped on 
gravel.

> I thought the point of ABS was to increase
> CONTROL (steering) during heavy breaking, not so much to 
> decrease
> stopping distance.

Yes & No.
ABS generally decreases stopping distances and that is a 
major aim, as is increased control.

Optimum stopping typically occurs when the tyres are 
slipping at about 10 - 15% of their rolling speed. More than 
that and skid onset is imminent. Less than that and you 
could get more stopping. A really really really competent 
driver may be able to hold a vehicle in this region. Joe 
average hasn't a show. ABS allows you to do this with ease 
and concentrate on steering and avasion and ... .

> In fact, I'm surprised that ABS *ever* decreases
> stopping distance...

As above.

I've read that cars with ABS rates have a higher percentage 
of solo male fatalities than cars without. That makes sense 
:-) - but the reasons may not be what they first seem. eg it 
could be that males who drive by themselves are more likelt 
to buy cars with ABS brakes.


        Russell


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