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US DOT releases results from NHTSA-NASA study of unintended acceleration in Toyota vehicles; electronics not at fault

The US Department of Transportation released results from a ten-month study of potential electronic causes of unintended acceleration in Toyota vehicles. The National Highway Traffic Safety Administration (NHTSA) launched the study last spring at the request of Congress, and enlisted NASA engineers with expertise in areas such as computer controlled electronic systems, electromagnetic interference and software integrity to conduct new research into whether electronic systems or electromagnetic interference played a role in incidents of unintended acceleration.

NASA engineers found no electronic flaws in Toyota vehicles capable of producing the large throttle openings required to create dangerous high-speed unintended acceleration incidents. The two mechanical safety defects identified by NHTSA more than a year ago—“sticking” accelerator pedals and a design flaw that enabled accelerator pedals to become trapped by floor mats—remain the only known causes for these kinds of unsafe unintended acceleration incidents. Toyota has recalled nearly 8 million vehicles in the United States for these two defects.

We enlisted the best and brightest engineers to study Toyota’s electronics systems, and the verdict is in. There is no electronic-based cause for unintended high-speed acceleration in Toyotas.

—US Transportation Secretary Ray LaHood

In conducting their report, NASA engineers evaluated the electronic circuitry in Toyota vehicles and analyzed more than 280,000 lines of software code for any potential flaws that could initiate an unintended acceleration incident. At the Goddard Space Flight Center in Maryland, NASA hardware and systems engineers rigorously examined and tested mechanical components of Toyota vehicles that could result in an unwanted throttle opening. At a special facility in Michigan, NHTSA and NASA engineers bombarded vehicles with electromagnetic radiation to study whether such radiation could cause malfunctions resulting in unintended acceleration. NHTSA engineers and researchers also tested Toyota vehicles at NHTSA’s Vehicle Research and Test Center in East Liberty, Ohio to determine whether there were any additional mechanical causes for unintended acceleration and whether any of the test scenarios developed during the NHTSA-NASA investigation could actually occur in real-world conditions.

NASA found no evidence that a malfunction in electronics caused large unintended accelerations.

—Michael Kirsch, Principal Engineer at the NASA Engineering and Safety Center (NESC)

While NASA and NHTSA have identified no electronic cause of dangerous unintended acceleration incidents in Toyota vehicles or any new mechanical causes beyond sticking pedals and accelerator pedal entrapment, NHTSA is considering taking several new actions as the result of today’s findings, including:

  • Propose rules, by the end of 2011, to require brake override systems, to standardize operation of keyless ignition systems, and to require the installation of event data recorders in all passenger vehicles;

  • Begin broad research on the reliability and security of electronic control systems;

  • Research the placement and design of accelerator and brake pedals, as well as driver usage of pedals, to determine whether design and placement can be improved to reduce pedal misapplication.

NHTSA and NASA will also brief the National Academy of Sciences panel currently conducting a broad review of unintended acceleration and electronic throttle control systems on the reports released today.

Based on objective event data recorder (EDR) readings and crash investigations conducted as part of NHTSA’s report, NHTSA is researching whether better placement and design of accelerator and brake pedals can reduce pedal misapplication, which occurs in vehicles across the industry. NHTSA’s forthcoming rulemaking to require brake override systems in all passenger vehicles will further help ensure that braking can take precedence over the accelerator pedal in emergency situations.

The ongoing National Academy of Sciences study, which will examine unintended acceleration and electronic vehicle controls across the entire automotive industry, will also make recommendations to NHTSA. The NAS study was launched in spring 2010 alongside the NHTSA-NASA investigation and will be finalized later in 2011.

In 2009 and 2010, Toyota recalled nearly eight million vehicles as part of the sticky pedal and pedal entrapment recalls. Toyota also paid $48.8 million in civil penalties as the result of NHTSA investigations into the timeliness of several safety recalls last year. Across the industry, automakers voluntarily initiated a record number of safety recalls in 2010.




" require the installation of event data recorders in all passenger vehicles."

Unless this is just a few dollars for reprogramming/memory per car - forget it.


A simple basic low cost over ride mechanism should be sufficient.


"A simple basic low cost over ride mechanism should be sufficient."

OnStar already has this, they can disable the gas pedal by request from the police if your car is stolen.


The brake override should have been a design requirement from before day one. Any competent controls engineer would expect to have such a failsafe as a matter of course. The fact that many other carmakers included brake overides in their fundamental drive-by-wire designs, such as Chrysler, GM and Ford fully indicates this failure.

The absences of such routine safety design, is a management decision made for economic savings. For which error, Toyota should and will pay, dearly.

There is a Theorem of software design and development that you can never say there are no longer any bugs in a piece of software. All you can say is merely that none, (or very few instances), have been observed recently.

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