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NASA report: Blame floor mats and pedals, Toyota already addressed acceleration problems

Consumer Reports News: February 08, 2011 05:09 PM

A series of accidents and reports of runaway acceleration in Toyota vehicles was not caused by electronic flaws, says a report today by the National Aeronautics and Space Administration (NASA), wrapping up a 10-month investigation.

"The verdict is in. There is no electronic-based cause for unintended high-speed acceleration in Toyotas. Period," said Transportation Secretary Ray LaHood in a press briefing in Washington this afternoon.

"As we stated last year, there are only two real-world causes of high-speed unintended acceleration in Toyotas. First, some Toyota floor mats entrapped drivers' gas pedals while their vehicles were in motion. Second, so-called 'sticky pedals' made some Toyota accelerators too slow to release."

Those were the two problems identified in separate recalls by the automaker in late 2009 and early 2010. NASA said that no cause was found in which a problem leading to unintended acceleration could also affect the brakes. But the space agency did acknowledge that pumping the brakes could render them ineffective, as demonstrated in our video.

In written response to the report Toyota said: "We believe this rigorous scientific analysis by some of America's foremost engineers should further reinforce confidence in the safety of Toyota and Lexus vehicles... We will also continue to cooperate fully with NHTSA and respected outside experts in order to help ensure that our customers have the utmost confidence in the safety and reliability of our vehicles."

NASA studied 40 Toyota vehicles, including several that the National Highway Traffic Safety Administration (NHTSA) had purchased from consumers after they were involved in unintended acceleration incidents. Among other tests, they bombarded them with radiation at a Chrysler facility in Michigan to test for electromagnetic interference. They also tore down several systems.

NASA principal engineer Michael Kirsch says they were given access to Toyotas design schematics and warranty claims data and didn't see the types of indications that would lead them to suspect an electronic problem. And they found no incidents or scenarios that could trigger unintended acceleration without also setting a trouble code in the vehicle's electronics.

NASA did find two instances in Toyota's warranty claims data in which an electronic problem did result in unexpected acceleration. In one such case, the throttle was only open 15 percent, a diagnostic trouble code was triggered, and in testing a car in such a state, NASA engineers described it as "undriveable."

Kirsch also noted that unlike in NASA spacecraft and other forms of transport, safety problems related to systems other than brakes do not trigger red warning lights or other warnings that would cause a driver to take immediate action.

In response to the study, NHTSA Administrator David Strickland identified three regulations the agency will consider implementing to combat potential unintended acceleration:
  • Require all cars to be equipped with brake override, which closes the throttle in the event the brakes and accelerator are applied simultaneously.
  • Pass standards for keyless ignition systems that will make it easier for drivers to know how to shut off a car in the event of a problem.
  • Implement standards requiring event data recorders in all cars. A 2006 NHTSA mandate defines detailed monitoring requirements for EDRs, including which systems should be recorded and for how long. These standards must be implemented in EDRs that are installed in the 2013 model-year cars. We encourage carmakers to apply these monitoring standards to their vehicles as soon as possible, with the appropriate privacy controls.

These are three of the recommendations Consumer Reports made following the tragic, high-profile acceleration incident in August 2009. (Read: "Consumers Union calls for changes to strengthen U.S. car-safety net.") We would also like to see transmission shifters that are more intuitive and better labeled, making it easier for drivers to engage Neutral in emergencies. We support NHTSA in moving forward on these rulemakings in a timely fashion.

Longer term, NHTSA plans to hire more engineers with electronics and human factors expertise. This sounds like a smart investment. In fact, Consumer Reports employs a full-time human factors engineer at our own auto test track.

With accelerator pedal entrapment being one of the mechanical causes NASA identified as leading to unintended acceleration, NHTSA now sees pedal placement and design as critical safety issues and hopes to devise standards to govern them.

The NASA report is the first of two studies commissioned by NHTSA to investigate unintended acceleration. It focused on the design and performance of Toyotas. The second report, reviewing sudden unintended acceleration across the auto industry, is being conducted by the National Academies of Science and is due out later this year.

For more information on unintended acceleration and what lead to the investigation, visit our unintended acceleration guide.

—Eric Evarts and Ami Gadhia

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