In a follow-up story to the one the paper did last week (and one I also discussed) concerning the fatal sudden acceleration crash involving a ToyotaLexusES 350, the Sunday edition of the LA Times said that a National Highway Traffic Safety Administration (NHTSA) investigation into the accident found that the car's gas pedal design may have been a contributing factor.
As a result of the crash, Toyota recalled 3.8 million Toyota and Lexus cars last month to remove their floor mats which could jam the gas pedal in the full throttle position (also called "floor mat entrapment").
The LA Times article says that while the NHTSA has not drawn any conclusions about the cause of the San Diego car crash that killed California Highway Patrol Officer Mark Saylor and three members of his family, investigators did find that in regard to the design of the Lexus' accelerator,
"Beyond the main pivot, the lever is not hinged and has no means for relieving forces caused by interferences,"
The LA Times noted that Toyota is considering a redesign of its gas pedal as a solution to its current floor mat problem.
The NHTSA also said in its report that instructions for turning off the Lexus while it is engaged were "not indicated on the dashboard."
As I mentioned before, to turn off the Lexus ES 350 which has a electronic pushbutton ignition, you must hold down the start button for three seconds. The current Lexus ES 350 user's manual does state this fact, but I don't believe there is any requirement for placing a warning about this procedure on the dashboard, as far as I know.
For those readers who own or have driven cars with electronic ignitions, let me know if there is (or is not) any warning label on how to turn your car off in an emergency on the dashboard, if you would. Please include the make and model of the car.
A couple of tidbits of extra information related to this story I found in doing some background research.
Runaway cars has been a problem for at least thirty years, and has happened so often that it has a formal name: "sudden unintended acceleration" or SUA. A San Diego Union-Tribunestory says that there have been over 24,000 consumer complaints to the NHTSA regarding SUA over the past ten years involving almost every car manufacturer. The NHTSA has conducted some 20 investigations over that time and has ordered over 30 SUA-related recalls.
According to this blog post in the New York Times, in March 2007 the NHTSA undertook an investigation of 2007 model Lexus ES 350 after receiving SUA complaints from five drivers. As a result of their investigation, in September 2007, Toyota issued a recall of 30,500 2007 and early model 2008 Lexus ES 350 and 24,500 2007 and early model 2008 Toyota Camry optional All Weather Floor Mats because they could lead to possible accelerator entrapment.
The New York Times post said that the NHTSA continued after the recall was issued looking at the SUA problem in Lexus cars, and found that they could not find any electronic nor magnetic field source for the reported SUA. What they did find, however, was that the car's accelerator design allowed it to easily become entrapped by driver side floor mats when they were not secured properly.
In addition, the NHTSA found braking issues once a Lexus ES 350 experienced SUA: "With the engine throttle plate open, the vacuum power assist of the braking system cannot be replenished and the effectiveness of the brakes is reduced significantly;" stopping distance "increased from less than 200 feet to more than 1,000 feet."
More interestingly, the New York Times post says that the requirement to depress the start button 3 seconds to stop a Lexus ES 350 once it was moving apparently was not in the car's user's manual until the 2009 model.
It is in the 2009 Lexus user manual, but I would think that Toyota might want to send a notice to drivers of their older model cars.
It turns out that Toyota engineers choose the 3-second requirement on purpose. They didn't want drivers accidentally turning off the car's engine by inadvertently hitting the start button, which would make the car difficult to control because power to steering and other controls would be lost.
The USA Today story quotes a Toyota spokesperson as saying, "That feature [the 3-second deactivation requirement] is a safety feature in (and of) itself. We want to make sure the engine is not shut off inadvertently by touching the button."
However, the other half of the safety equation - desiring to deliberately shutting the engine off - apparently seemed to escape whoever was responsible for approving the Lexus user's manual.
The USA Today story also says that Toyota does not currently have plans to put a warning label near its starter buttons, and also that the NHTSA currently believes that it sees nothing intrinsically wrong with push button starters.
USA Today quotes an NHTSA spokesperson as saying that, "It's a new technology that drivers need to familiarize" themselves with.
I guess it would help if manufacturers bothered to explain fully how this feature and others did and didn't work to drivers of their cars.
Robert N. Charette is a Contributing Editor to IEEE Spectrum and an acknowledged international authority on information technology and systems risk management. A self-described “risk ecologist,” he is interested in the intersections of business, political, technological, and societal risks. Charette is an award-winning author of multiple books and numerous articles on the subjects of risk management, project and program management, innovation, and entrepreneurship. A Life Senior Member of the IEEE, Charette was a recipient of the IEEE Computer Society’s Golden Core Award in 2008.