Thoughts on Prius Acceleration

Tuesday, March 9, 2010 by darco
Posted in ,

I own a 2004 Toyota Prius, and it is the best car I have ever owned. The only car I want more than my current Prius is the 2010 model. And, yes, I have even experienced the "sudden unintentional acceleration" issue several years ago that so many people are up in arms about these days. Why am I still a loyal Toyota fan?

It was quite startling not having the gas petal bounce back to my foot after pressing down on it hard, but I survived because I am familiar enough with my car to know how to put it into neutral. At highway speeds the Prius requires you to hold it to neutral for a full half-second to engage. I was able to stop the car and figure out what happened.

It was the floor mat. It had come off the hooks when it was removed for cleaning and moved forward on the floor. The gas pedal had lodged under it. I fixed the floor mat and kept an eye on it after that, but never had any other issues.

I am convinced that most, if not all, of these sudden acceleration issues with the Prius are due to improperly installed floor mats. What shocks me is that these people don't know how to stop their vehicle. They may try putting it into neutral and it doesn't seem to work because they don't hold it in neutral long enough. They may try pressing the power button repeatedly (when they should be holding it down for three seconds) and they wonder why they keep accelerating. They pump on the breaks, smell something awful, flip out, and then they die.

Unless it can be proven that there is some sort of Prius "death mode" coded into the software (doubtful), I think that these deaths are best attributed as operator error rather than something that is the fault of Toyota. A properly installed factory floor mat will not cause "sudden unintentional acceleration", only a loose one.

All that being said, I think Toyota should make three software changes to help out those who panic or simply don't know how to operate their vehicle:

  1. If the throttle is at full, remove any delay on switching to neutral.
  2. Interpret repeated pressing of the power button as a signal to shut down the engine, even if the power button was not held down for three seconds.
  3. If the throttle is at full and the power button is pressed, immediately switch to neutral.

This will help save the lives of those people who would otherwise kill themselves.


I just wanted to comment on some stories that are relevant to this issue. It seems that in the most recent case of a run-away prius may be due to a jammed accelerator pedal (without interference from loose floor mats), contrary to my hypothesis in article above.

What I did find interesting is that despite repeated orders from the 911 dispatcher and the CHP officer to put the vehicle into neutral, the man absolutely refused to do so:

Leighann Parks, a 24-year-old dispatcher, repeatedly told him to throw the car into neutral but got no answers.


Neibert told Sikes after the CHP caught up with him to shift to neutral but the driver shook his head no. Sikes told reporters he didn't go into neutral because he worried the car would flip.
(Excerpt from The Associated Press)

In other words, none of the software additions that I mentioned in the article above would have helped this guy. Fear petrified him to the point of disobeying a police officer.

Just in case anyone is wondering, it is safe to put any car into neutral at any speed. It can save your life. It saved mine.

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