In the 80s, my mom had an Audi 5000. It’s value was destroyed by allegations of sudden, uncontrollable acceleration. No plausible physical mechanism was ever identified.

Today, Toyota’s suffering from the same fate. A more likely explanation? Operator error. Stepping on the gas instead of the brake transforms the normal negative feedback loop controlling velocity into a runaway positive feedback:

… A driver would step on the wrong pedal, panic when the car did not perform as expected, continue to mistake the accelerator for the brake, and press down on the accelerator even harder.

This had disastrous consequences in a 1992 Washington Square Park incident that killed five and a 2003 Santa Monica Farmers’ Market incident that killed ten …

Given time, the driver can model the situation, figure out what’s wrong, and correct. But, as my sister can attest, when you’re six feet in front of the garage with the 350 V8 Buick at full throttle, there isn’t a lot of time.

Read more at the Washington Examiner

5 thoughts on “Feedbackwards”

  1. I recall a different summary in Comp.risks, where I read:

    “… The study, “An Examination of Sudden Acceleration,” explored … electromagnetic and radio frequency interference and malfunctions in cruise control, electronic idle-speed control systems, computer-controlled fuel injection systems, transmissions, and brakes. The investigators could find no
    mechanism — besides actuation of the gas pedal — that would open the throttle sufficiently to accelerate any of the cars studied at full power.

    However, there was evidence of minor surges of about three-tenths of the Earth’s gravity for 2 seconds caused by electronic faults in the idle stabilizer systems of the Audi 5000 ….”

    It’s rather astonishing to me, having felt that much of a sideways jerk in an earthquake, just once, to know they dismissed an _acceleration_ of 3/10g. One of the readers at Risks said the same thing in clearer language:

    Minor?? .3G works out to roughly 10 feet/sec^2, or a zero-to-sixty acceleration time of about 9 seconds. This may not be considered “full power” or “major” acceleration for a sports-car, but my old Volvo has difficulty reaching highway speed (55) in 9 seconds even if I floor the accelerator.

    A .3G surge for 2 seconds would accelerate a car from a standstill to somewhere
    in the neighborhood of 20 feet/second, and would carry the car about 10 feet forwards. Startling? I should say so… especially to drivers who might have only recently switched to the Audi from an older, lower-powered car.

    Even if this fault in the idle stabilizer cannot invoke “full”
    acceleration by itself, it sounds substantially dangerous in and of itself. Coupled with poor pedal/linkage layout and design, it apparently adds up to a real hazard.

    Dave Platt FIDONET: Dave Platt on 1:204/444

  2. Oh, and don’t miss the two other comments immediately below Dave Platt’s at Risks. He wasn’t the only one to write in about the magnitude of the effect that was dismissed in the report.

  3. Definitely strange to blow off .3g, but it’s also a weird unit of measure for the reported finding. I guess that was a test of a car sitting at idle, in gear, with no foot on the brake?

    I remember reading at the time that one big issue was pedal layout: the 5000 had a typical European layout with close gas-brake spacing, and had an unprecedented crossover of buyers from cushy American sedans, who wouldn’t have been used to that.

  4. > I guess
    I dunno, but I found out what it’ll cost ya to find out:

    > Pollard & Sussman, “An Examination of Sudden Acceleration,”
    > NHTSA, 1/1989, report DOT-HS-807-365, NTIS reference
    > PB-89-158786, available for $70-$80 from NTIS

    I found that here:
    along with this definition–if I read this right, what you think is ruled out, but I can’t tell what they _would_ consider sudden acceleration:

    “… I recently received a mail from a fellow who insisted that he had experienced a sudden acceleration event for no apparent reason while he was stopped and lightly holding the brake pedal. The result was his car’s engine revving up 500 to 700 RPMs momentarily, which dragged him forward a car-length …. I explained to him that this was NOT a sudden acceleration as defined by NHTSA or myself (see above). Such engine idle speed changes can be commanded by the engine control module for a variety of reasons, and do not fall into the S/A catagory ….”

    I wonder what the other categories are?

  5. I have to admit that I’m interested, but not $80 interested.

    The sudden acceleration account seems strange. I drive a stick (one sure way to always be able to cut the engine out), but on the rental I had yesterday, revving the engine 1000rpm did nothing to move the car. “Lightly” would have to be really incredibly minimal braking.

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