The National Highway Traffic Safety Administration proposed changing accelerator testing standards for most new cars and many trucks and buses. The override systems, which automatically activate if the accelerator and brake are touched simultaneously, would be required in passenger cars, trucks and buses weighing less than 10,000 pounds. Most large trucks and buses weigh more than that, however.
Many vehicle models already come equipped with such brake-throttle override systems, which give the brake primacy.
The proposal is an outgrowth of investigations two years ago into claims that electronic defects were causing unintended acceleration in some Toyota models. An investigation by NHTSA and a separate study by NASA concluded that there were no electronic defects, but that in some cases drivers had inadvertently pressed the brake and gas pedal at the same time or that gas pedals had become trapped.
One accident that gained attention was the August 2009 high-speed crash of a Lexus near San Diego that resulted in the deaths of four people. Investigators determined that the driver, a veteran California highway patrolman, had applied the brake of the loaned car but was unable to override the accelerator, which was trapped by a floor mat.
In February 2011, Toyota Motor Corp. recalled 2.17 million vehicles in the United States to address accelerator pedals that could become trapped in floor mats or jammed in driver's-side carpeting, prompting NHTSA to close its investigation. The agency also fined Toyota $50 million for not recalling millions of vehicles in a timely fashion.
The proposed standard aims to minimize the risk that drivers will lose control of their vehicles as a result of either accelerator-control system disconnections or accelerator-pedal sticking or floor-mat entrapment, the safety administration said.
"While NHTSA's defect investigation program will continue to monitor and consider consumer complaints of any potential vehicle safety issues, this proposal is one way the agency is helping keep drivers safe and continuing to work to reduce the risk of injury from sticky pedals or pedal entrapment issues," David Strickland, NHTSA's administrator, said in a statement.
The auto industry urged two years ago that override systems be standard on new vehicles, said Gloria Bergquist, vice president of the Alliance of Automobile Manufacturers. She said the alliance would review NHTSA's proposal.
But safety and industry experts said the proposal doesn't address the larger issue of drivers who mistakenly press down on the accelerator when they mean to apply the brake.
Such "pedal misapplication" is a much larger problem, said Clarence Ditlow, executive director of the Center for Automotive Safety. Relatively few drivers apply both the brake and accelerator at the same time, and cases of accelerators becoming jammed are not common, he said.
NHTSA has been working on regulations to address the placement of gas pedals relative to brakes to prevent such mistakes, but there has been no indication when a proposal might be offered, he said.
Jeremy Anwyl, vice chairman of car-shopping guide and automotive research publisher Edmunds.com, said NHTSA's proposal to require the override system "could provide a false sense of security for drivers, especially in cases where a driver accidentally applies the wrong pedal, and an override will do nothing to solve the problem."
The wording of NHTSA's 129-page proposal effectively gives automakers about three years before the requirement for brake-throttle override systems kicks in, Henry Jasny of Advocates for Highway and Auto Safety said.
The public has 60 days in which to comment.
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