The poop on ABS

[Dan Brideau <dan@hobbyetc.com>]

Friends and neighbors,

ABS equipped cars see, on average, a 6.5% stopping distance benefit over similar non-ABS cars.

You non-believers in ABS got me worked up.  Month after month I see complaints that your cars are too slow, and what can I do to make it go faster.

There were a few of you who actually felt their cars stopping performance was too good.  If that's the case, I'm sure I could find a few of you who get laid too much, have too much cash, and too much time to wax your hoods.

Seems every racing organization I can think of doesn't allow ABS.  This gives me the impression that there may be some advantage to be had.

I figured I should do some research, and decide if ABS was a hoax, or if there was any merit to it.  It should be easy to determine.

A. Do some stops with ABS turned on
B. Do some more stops with ABS turned off
C. Write down which one is shorter more often

So, here are my findings:

First, car magazines never test "stripper" cars.  They always test nearly, or fully optioned cars.  Options that always include ABS.  This meant I would need to find some other source for hard data.  I don't like to speculate on things that can be easily measured. 

Second, the car manufactures I looked at don't publish stopping performance.  This includes VW, Toyota, BMW, Dodge, and Mercury.  This is based on a web site survey done by me.  Looking under both performance and safety listings for various models.  This doesn't surprise me.  I can imagine the suits that would emerge.  (This car is supposed to stop at this speed in this many feet - so how come I still ran over that little kid...)

The third place I looked was the NHTSA.  This is where I found the most information.  There I found several reports regarding to the safety history of cars with ABS vs. cars without.  Two points stood out from these:

A. The overall accident rate was unaffected by the introduction of ABS.
B. Many people use ABS incorrectly

However, this was not the purpose of my research.  I am interested in stopping distance.  However, I can see how the misconceptions of ABS can propagate seeing this information.  I'm not sure what "many people" amounts to, but that’s another project.

Further reading lead me to a report called "A TEST TRACK PERFORMANCE EVALUATION OF CURRENT PRODUCTION LIGHT VEHICLE ANTILOCK BRAKE SYSTEMS".  There was no date on the paper, but the model year of the cars tested was 1996.  This is a report on the findings of 8 test vehicles that employed 8 different types of ABS systems.  At the time there were 8 manufactures of ABS systems.

The bottom line on this report is this: 

A. On 13 surfaces, 2 (grass and loose gravel) saw a increase in stopping distance.
B. ABS equipped cars see, on average, a 6.5% stopping distance benefit over similar non ABS cars.

If you have any other statistical data on ABS, let me know.  You can read this report and find some links on my Scirocco web site: http://www.hobbyetc.com/scirocco


Dan Brideau
http://www.hobbyetc.com/scirocco


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