Having lived for the past 15+ years in a state (Montana) where adverse 
driving conditions are a way of life for a large chunk of the year, I 
can say that I'm definitely familar with ABS vs non ABS.

With a few exceptions, driving in snow/ice (and I guess normal driving 
as well) is all about retaining "adhesion" to the road surface.  By 
adhesion I mean that the tire treads and the road surface are moving 
together (or I guess opposite to each other).   Any skid/slide in any 
direction means you are unadhered to the road.  I should also mention 
that I do use some words like stuck in their 'adhesive' meaning below - 
so be aware.

The reason why remaining adhered to the road is important is that 
without that adhesion, you have no control of the vehicle.  It goes 
where it wants to, no matter where you turn the wheels.  it should also 
be noted that once adhesion is lost, it is quite hard to get it back.  
All of the rules such as "turn your wheel into the skid" and similar are 
all about trying to get the wheels re-adhered to the road.

So, we're talking about braking here.  In a Non-ABS vehicle, if you hit 
your brakes really hard (or even barely in some conditions), the tires 
lock up, and become unstuck from the road.   As a result, you loose 
steering, and all control.   It is really easy to get into a skid in an 
non-abs vehicle.  Just hit the brakes on packed snow and ice.   Your 
wheels will lock up, even briefly, and you'll end up in a ditch.   A 
good driver can and will get used to how much pressure and/or in what 
manner to apply it and will actually simulate the action of an ABS system.

With ABS, it's harder to loose adhesion.  Yes, sometimes conditions are 
bad enough that even a slight tap will do it, and abs isn't fast enough 
on some vehicles to handle it.   But for the most part, braking an ABS 
vehicle will always help.   Yes, you can come unstuck doing things which 
involve lateral motion - yanking the wheel, or going around a corner too 
fast for conditions.   But when it's braking which is involved, becoming 
unadhered is a lot less of a concern.  

About the only place where ABS hurts is where you are trying to stop in 
the shortest amount of distance.   I'm not sure about dry-pavement, but 
I know that in sand and snow and other situations where a locked tire 
will tend to 'dig in', abs significantly increases stopping distances.  
This of course has to be balanced with retaining the ability to actually 
steer.  In an ABS vehicle one should apply firm pressure and do what 
they can to steer around the obstacle.   Contrast that with a non-abs 
system where one can either jam on the brakes, and hope they skid to a 
stop before the obstacle, or try to apply appropriate pressure to the 
brakes so that they can still steer around it.

Personally, I'm much more comfortable in an ABS-equipped vehicle.  It 
allows me to do less thinking in an emergency situation - in all 
situatitons the correct answer is hit the brakes and look for an escape 
path to drive around the problem area.

-forrest
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