Unintended acceleration

Louis-Alain Richard laraa at sympatico.ca
Wed Oct 21 19:57:05 PDT 2009

I'm with you Brett : driver's error. Of all events like that, it was always
driver error. Not his car, a pushbutton to stop the engine, the gated
shifter, it screams driver error. Panic did the rest.

Little story that happened to me when I was younger : while driving mom's
car, a Chevette stick shift, I decided to try to depress clutch with my
right foot, just to see. Dumb idea, since I had to stop at an intersection,
and my left foot couldn't touch the brake pedal... While knowing that I had
just to release the clutch to recover braking power, I was so surprised that
I did nothing at all, just kept my right foot to the floor as in an
emergency braking. Panic was what froze me. There was no car at this very
moment, so I escaped uninjured but I learned that reflexes are very strong,
stronger than any will. At least for a few seconds.


-----Message d'origine-----
De : quattro-bounces at audifans.com [mailto:quattro-bounces at audifans.com] De
la part de Brett Dikeman
Envoyé : 21 octobre 2009 21:54
À : Ed Kellock
Cc : cobram at juno.com; quattro at audifans.com
Objet : Re: Unintended acceleration

On Wed, Oct 21, 2009 at 8:52 PM, Ed Kellock <ekellock at gmail.com> wrote:
> An interesting read... it discusses vacuum assisted braking systems and
> inability of a car's brake system to stop it at full throttle, regardless
> assist.

Except it's a load of crap; they all have check valves, and brakes are
MUCH stronger than engines.  Think about the kind of torque you'd need
to get from 0-60 in 150 feet.  That's barely across a large traffic
intersection.  Yet, your brakes can do the opposite handily...

My 'R has vacuum-assisted brakes.  I assure you, they work very well,
including full-throttle-to-hard-braking transitions.  Even if the
engine shuts off, there is an auxiliary vacuum pump which kicks in any
time the ignition is on and vacuum pressure drops.  I was bored one
evening waiting for someone and played with it- you have to work
pretty hard to use up the vacuum faster than the pump can replace it
and exhaust the vacuum reservoir.  That's better than the hydraulic
assist, technically- two completely independent sources of brake

It's also curious why the car, which surely was throttle-by-wire,
didn't shut off the throttle when the brake was applied.  That's very
common behavior, has been for nearly a decade.  Why didn't the driver
attempt to put the car in neutral, switch off the ignition, etc?

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