Sunday, March 14, 2010

Credibility issues with Sikes' Prius story?

An AP story titled Investigators raise questions in Prius incident includes the text:

During two hours of test drives of Sikes’ car Thursday, technicians with Toyota and the National Highway Traffic Safety Administration failed to duplicate the same experience that Sikes described

One would hope one could get a clear answer as to the events with Sikes' Toyota Prius.


Toyota, U.S. Can’t Replicate Prius Acceleration

Sikes’s Prius has brake override software, which cuts engine power “if the brakes are applied with moderate to heavy force,” said Mike Michels, a spokesman for Toyota’s U.S. sales unit, based in Torrance, California.

The carmaker will hold a media briefing to announce preliminary findings from its investigation into Sikes’s Prius at 12:30 p.m. in San Diego, it said in statement distributed by PR Newswire.
[on March 15??]

The WSJ reported:

The agency [DOT] added that the Prius driven by Mr. Sikes is equipped with a system that detects when both the accelerator and brake pedals are pushed down. When the brake application is "moderate or greater," the system will close the throttle, allowing the vehicle to slow down and stop, the agency said.

The system worked when engineers performed a test drive of Sikes's vehicle, the agency said. Engineers also noted that "there was very little left of the car's brakes," the agency said. The inboard front brake pads were completely gone and the outboard pads were down to about two millimeters to 2.5 millimeters, it said, and the rotors were damaged.

"We would caution people that our work continues and that we may never know exactly what happened with this car," the agency said.

UPDATE on 15 March 2010, from the WSJ:

Toyota spokesman Mike Michels said the driver would have had to repeatedly press and release the brakes, and press and release the accelerator, to defeat a brake-override system designed to prevent runaway acceleration. The system cuts off acceleration once the brakes are firmly pressed.

"So the on-and-off action would have been required to keep the car going at any kind of high speed," Mr. Michels said.

Toyota said it tested the accelerator pedal and found it to be working properly. The front brakes showed severe wear and damage from overheating, which could come from repeated light application, Toyota said.

"Toyota believes there were serious inconsistencies with the account of event of March 8 and the findings of this investigation," Mr. Michels said at the press conference. He cautioned that Toyota's investigation was preliminary and said federal safety regulators continued to conduct their own investigation.

The high-speed drama in California undercut a Toyota effort to discredit its critics and reassure drivers that the Japanese auto maker's vehicles are safe.

UPDATE by Joel S. Hirschhorn

Enormous media attention was given to tests on a Prius vehicle belonging to San Diego resident James Sikes, 61. These tests last week were conducted by people from Toyota and the next to useless National Highway Traffic Safety Administration. Technicians could not duplicate what Sikes experienced. Actually, all they tried to duplicate was the inability to stop the car when both acceleration and braking were produced. In fact, the car was stopped. So what? What they could not create was the core problem: unwanted sudden acceleration. Their tests proved nothing.

It is particularly relevant that a number of runaway Toyota incidents have occurred months apart on the same vehicles. This means that these cars could behave perfectly normally nearly all the time, but that sudden acceleration events also occur mysteriously and unpredictably. No one can duplicate these sudden acceleration events because no one, especially Toyota engineers, has a clue why these events happen. All the real evidence, though circumstantial, points to some bizarre problem with the electronic control system.

NHTSA bought the gas pedal, throttle and two onboard computers from the Sikes vehicle for $2,500. That means that there may be some hope that traditional failure analysis methods might be used to find out through exhaustive testing and analysis exactly what is really going on. Something that Toyota has not done. If there is a highly complex defect in, perhaps, a semiconductor chip, for example, that only manifests itself under certain conditions, then really sophisticated examination might find it.


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