In a letter to the National Highway Traffic Safety Administration,
the Center for Auto Safety said that the computer code, or
algorithm, which determines when an air bag deploys in an accident,
may improperly turn off the air bag if the passenger is bounced in
his or her seat just before an accident.
Air bags are not designed to deploy when a passenger's weight is
below a certain amount, and a bouncing motion, even when the person
is belted, could reduce the weight registered by the seat sensor
linked to the air bag algorithm.
There have been 143 fatalities in front-impact crashes in 2000-2010
model year Impalas in which the air bags failed to deploy, according
to the center, and in 98 of them, the occupants were wearing safety
belts. It said it included the 2000-2002 models in the crash data
because it was possible that some of them contained the suspect
"We call on NHTSA to examine each of the fatal non-deployment
crashes to determine whether the air bag should have deployed and
why it didn't," Clarence Ditlow, the center's executive director,
said in the letter.
Ditlow credited accident investigator Don Friedman of Xprts LLC with
uncovering the alleged defect. Friedman in November had called on
NHTSA to open an investigation.
A NHTSA probe could ultimately lead to a recall.
"We will, of course, cooperate with NHTSA if it determines any
further action is needed regarding this petition," GM spokesman Greg
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NHTSA said in a statement it "has received and is evaluating a
petition about possible defects" in the deployment of air bags in
The air bag algorithm has also become part of the investigation into
a recall begun in February of 2.6 million Chevrolet Cobalts, Saturn
Ions and other GM models for a defective ignition switch that could
suddenly turn off the car's engine.
Questions have been raised about whether the largest U.S. automaker
was trying to conceal the problem, after years of consumer
complaints and at least 13 deaths linked to the faulty part.
NHTSA acting Administrator David Friedman told a congressional
hearing last week that his agency's investigators were surprised to
learn that turning off the engine caused the air bags to deactivate
immediately in the recalled GM cars.
He said the agency was examining what role, if any, the algorithm in
the recalled cars had in the air bags not deploying in accidents.
(Reporting by Eric Beech; editing by Peter Cooney and G. Crosse)
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