Radiation from space long has affected airplanes and spacecraft, and is known for triggering errors in computer systems, but has received scant attention in the auto industry.
The questions show how deep regulators and automakers may have to dig to solve the mysteries of sudden acceleration.
But at least half of more than 1,500 recent complaints to regulators involve other models, raising questions whether
An anonymous tipster whose complaint prompted regulators to look at the issue said the design of
"I think it could be a real issue with
Electronics makers have known for decades about "single event upsets," computer errors from radiation created when cosmic rays strike the atmosphere.
With more than 3,000 complaints to U.S. regulators of random sudden acceleration problems in
The phenomenon can trigger software crashes that come and go without a trace. Unlike interference from radio waves, there's no way to physically block particles; such errors typically have to be prevented by a combination of software and hardware design.
And an anonymous tipster told NHTSA last month that "the automotive industry has yet to truly anticipate SEUs."
Such radiation "occurs virtually anywhere," said
Testing for the problem would involve putting vehicles in front of a particle accelerator and showering them with radiation, a step that experts said would help resolve the question.
"Nobody wants to come out and say, 'We have issues, and we need to test,' " said Chung, president of the testing firm Eigenix.
The phenomenon was first noted in the 1950s to affect electronics at high altitudes; unlike electromagnetic waves, there are no ways to physically shield circuits from such particles. Airplane and spacecraft makers have long designed their electronics with such radiation in mind, through safeguards such as systems that triple-check data.
Only in the late 1970s did researchers discover that a minuscule portion of such radiation falls to earth. It's not enough to harm humans, but as circuits in computers and cell phones on the ground have shrunk to the width of several dozen atoms, the risk of errors has grown. "Five years ago, it was a problem in very few applications," said Olivier Lauzeral, general manager of IRoC Technologies, which tests chips and software for SEU resistance. "In the past couple of years, we've seen a rise in demand and interest."
In an anonymous e-mail last month to the
NHTSA added the tipster's information to its electronic investigative file on
Electronic throttle controls like the ones under scrutiny in Toyotas are widespread in the industry. They're more reliable than mechanical links; they save weight and space; and they make other technology, like stability control, possible.———
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