From: tpickett@auspex.com (Tom Pickett)
Newsgroups: rec.autos
Subject: Re: Anti-Lock Brakes makes stopping SAFER?
Date: 30 Dec 92 16:22:01 GMT
Reply-To: tpickett@auspex.com (Tom Pickett)
Organization: Auspex Systems, Inc.  Engineering

In article <1992Dec29.212850.21199@pencom.com>, stecz@pencom.com (John 
Steczkowski) writes:
> Actually hitting the object with the front of the car is better than the 
side.  
> Try this...sit in your car, measure the distance from your nose to the 
drivers  
> side window.  Now measure the distance from your nose to the windshield.   
> Notice how there is a lot more car to smush in front than the side.  This 
is a  
> good thing.  Actually, one of the advantages to ABS is that it prevents you  

> from sliding sideways in a wreck.  
> 
> Remember, your tires have more traction not sliding, than sliding.  In your  

> scenario, without ABS, you would have slid sideways, and since your tires 
are  
> now sliding, you would have taken longer to stop, probably hitting the 
other  
> car with the passenger side door (at least that is how it sounds from the  
> description).  What if you would have had  a passenger?  Their head would 
have  
> hurt awfully bad after getting smashed into the window. (remember seatbelts 
and  
> airbags aren't as effective in a side collision as in a front collision).  
> > 
> > If the ABS had not been sufficient to stop me, I would have certainly
> > been prevented b\from using the skid to lessen the impact.  The skid
> > would have:
> > 
> > 	1. scrubbed speed off from the drag produced thereby reducing
> > 		impact.
> 
> Not as much as stopping straight without the tires sliding.
> 
> > 	2. Spread the impact over a wider surface area, causing the car to
> > 		take the impact instead of the human body.
> 
> yes, but with a lot shorter crumple zone (inches instead of feet), probably  

> injuring the people inside more.
> 
> > 	3. Might have allowed me to steer around the other car had they come
> > 		to a stop, by converting the skid into forward motion allowing
> > 		me to "drift" around the other car.
> 
> Not likely, once you are skidding, it is fairly difficult to recover.  Have 
you  
> ever autocrossed?  It's a lot tougher to do than you think.  I know, I know  

> you're a great driver, and you've done it before. But the question is, can 
you  
> do it again?


The impact is lessoned to the extent of making it fairly reasonable.  this is
all at low speed, and the scrubbing of the tires makes it even slower.

It is not necessary to make statements like "I know you are a great driver,"
I have no misconceptions about my ability to drive. I presume from your
statement that you have autocrossed, so perhaps you feel you are a better
driver than I, and you may be.  Perhaps I haven't been driving as long as
you have either.:-)

My concern is whether or not ABS is 
necessarily the best thing to have in certain situations where it might
be possible to reduce the impact of an accident in an unconventional
way.

I would not necessarily have taken longer to stop, I don't know.  There
is a lot of drag created by sliding sideways on yuour tires, but I have
to admit that such a maneuver is predicated on the assumption that an
impact is imminent and not avoidable.  That I was able to stop in this
case is a good point for ABS, but I'm not sure I would have been better
off going straight into the offending car.  By spreading the impact
over a larger area, I might have lessened the damage to the car.

Incidently I wouldn't use such a maneuver if the speeds were high or
if I had a passenger.

I also wonder if ABS actually does stop a car any faster than a good
driver can by simply modulating the pedal.  I also question the efficacy
of ABS on slippery surfaces such as grass, snow, ice, etc... .

I think for commuting (ie, in heavy traffic) ABS is probably a good
thing, but I definitely question its use under different circumstances.



Tom Pickett 
tpickett@auspex.com or 74616.2237@compuserve.com
SHO  GOZE