Prius Unintended Acceleration: Electronic Faults Untraceable

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2009 Toyota Prius

2009 Toyota Prius

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A new report from a National Academy of Sciences panel has said that the NHTSA was justified in closing a probe into Toyota's 2009 and 2010 unintended acceleration cases.

More than 8 million Toyota and Lexus vehicles, including models like the Toyota Prius hybrid, were recalled worldwide to fix alleged faults that were claimed to be responsible for a spate of car accidents.

Automotive News reports that Louis Lanzerottie, a New Jersey Institute of Technology physics professor, explained that "It's impossible to prove a complete negative, but all the data available to us indicated the conclusion that there was no electronic or software problem".

Toyota launched an investigation into potential software and electronic throttle faults, but found no issues. The company did fix sticky gas pedals and relocate floor mats, that could potentially result in the throttle becoming jammed open.

Toyota also concluded that driver error was to blame in several instances, where drivers had pressed the gas pedal to the floor, rather than the brake pedal. The company had gathered data from the car's in-built black-box recorder, that stores data from the seconds before and after an accident.

However, the report does stress that an electronic cause for unintended acceleration hasn't been ruled out completely - only that it's completely untraceable.

The NHTSA closed its inquiry as no evidence was found that unintended acceleration causes were due to electronics. Critics claim this shouldn't be used to exonerate Toyota simply through lack of data.

We're not so sure - in a legal system that practices "innocent until proven guilty", absence of proof should really be enough to prevent a witch hunt...

Both Toyota and the NHTSA are determined to make improvements, even so. Toyota said "We share the goal of NAS and NHTSA to make America's vehicles even safer" in a statement on the company's website.

The NHTSA is looking into ways of ensuring similar situations aren't repeated, including failsafes that allow the brake pedal to override accelerator input. The design of gas and brake pedals is also being looked into.

Toyota is rightly still in the clear for the time being, but we're sure this is a debate that will continue to rumble on...


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Comments (3)
  1. Worth repeating. Prius owners (and others), if this does ever actually happen, move the shift lever to neutral and hold it there for one second. If that fails, press and hold the power button for three seconds until the car shuts off. This safe to do even if you are moving.

    What we should learn from this incident (real or not) is how to respond if it does happen.

  2. The most publicized case of acceleration turned out to be pure fraud for the San Diego fellow - awash in debt (based on news reports of his finances) and looking for a payday in my opinion. His car immediately stopped when investigators simulated the situation. And for the others, just like the elderly woman who floored her car and smashed my mother's in a parking lot, some people are just not aware enough to be safely driving. This all has hurt Toyota's reputation because people would rather demonize a well intentioned company than own up to real human frailties.

  3. You're right, it was a witch hunt. Businessweek said the same:
    A year later, after the NHTSA/NASA exonerated Toyota, B-week said "the media owe Toyota an apology."
    Regarding the so-called sticky pedals, Car and Driver said that the projected effect added a negligible risk of being in an accident, saying you were more likely to be in an accident of any another cause.
    Motor Trend dismissed allegations that electronic issues could cause unintended accel. or brake failure, a year before NHTSA released the report stating same.
    MT also tested recalled Priuses and tried to force brake failure and unintended accel.--and couldn't, casting doubt on the need for recalls.

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