With a federal investigation this week shifting much of the blame for Toyota's unintended-acceleration incidents onto drivers, the National Highway Traffic Safety Administration announced that it would study ways of designing car pedals to prevent people from confusing the brake and accelerator.

But similar efforts have fizzled in the past, in part because of industry opposition. In 1989, after unintended acceleration in Audis caused a similar furor, federal studies twice proposed changes to pedal size and placement.

The recommendations, the result of three collective years of research, never made it into law, and it took the agency decades to mandate another design recommendation that safely secures the brake before motorists start their engines.

NHTSA officials, in a statement, said there was "no basis for regulation" in the earlier recommendations for pedal configuration.

But critics, including a former chief of the agency, said NHTSA dropped the effort after protests from the industry. Similar opposition stalled auto safety legislation in Congress last year.

"They'll never institute a standard for pedal placement," said Joan Claybrook, former NHTSA chief. "And the reason is the industry doesn't want NHTSA to get involved in it. When it was proposed last year, they went crazy over that."

Auto Alliance spokesman Wade Newton said the safety benefits of pedal standardization are "still questionable" and that the industry supports further research instead of a legal mandate.

Incidents of unintended acceleration have claimed dozens of lives, and NHTSA officials have steadfastly said that, in the absence of a detectable vehicle defect, "pedal misapplication" is frequently the cause for such events.

The primary NHTSA report emerging from the sudden-acceleration complaints for Audi 5000 sedans in the 1980s - involving one out of every 155 vehicles - solidified this view and offered three recommendations to deal with it.

Two involved changing and standardizing the configuration of the pedals. A separate, 260-page pedal placement study proposed specific designs.

E. Donald Sussman, the lead author of the primary study, said automakers fought it because "it gets directly into their marketing. It would be the government designing cars for them."

And Michael Perel, chief of NHSTA's human factors division at the time, said it has been difficult to troubleshoot problems without creating new ones.

"If you set the pedals too far apart, you increase the reaction time you need," he said. "If you raise a pedal too high, then you have to be afraid of getting your foot caught."

At the time the report was issued, Perel wrote the agency's official response, saying it was a "good first step" but that further study was needed. But in an interview, Perel said the matter was dropped because Audi installed a brake transmission shift interlock, a device that forces the driver to apply the brakes before putting the car in motion, and the rate of complaints decreased.

"The noise level dropped. The issue had moved on in terms of notoriety, which does drive research budgets," said Robert Quinn Brackett, senior research scientist at the Texas Transportation Institute and lead author on the 1989 pedal placement study.

Legislation stalls

Auto safety legislation introduced last year, in response to reports of runaway Toyotas, originally proposed that the Transportation Department adopt rules for pedal placement that, once passed, would be required in all passenger vehicles within two model years.

After industry opposition, however, a provision was added allowing the transportation secretary to go through rulemaking and then decide against the standard, provided the secretary returns to Congress with an explanation.

"It basically gives them an out," said Clarence Ditlow, executive director of the Center for Auto Safety. Both the House and Senate versions of the bill made it through committee but stalled before reaching the floor.

In addition to pedal placement, the 1989 study made a third recommendation to help prevent driver error with the brake interlock.

Although Audis were quickly redesigned to include the safety device, NHTSA did not require it of automakers.

"NHTSA rarely requires industries to do design changes, even when it involves safety issues. They hope they they will voluntarily do the right thing," said Sussman, who is a retired division chief with a Transportation Department research center.

It wasn't until 2006 - 17 years later - that NHTSA had a voluntary agreement in place with 19 automakers to install brake interlock in all cars, sport-utility vehicles and light pickup trucks, National Transportation Safety Board records show.

Congress ultimately passed legislation requiring it in all passenger vehicles, but that mandate just took effect last fall.

NHTSA criticism

The safety board has been critical of NHTSA, saying it has been slow to embrace similar standards for heavy-duty vehicles, records show.

In response to a rash of runaway school bus and truck incidents that left several people dead and injured over the past seven years, the safety board has been pushing for NHTSA to require the brake interlock for the rest of the vehicles on U.S. roads. They have also requested that NHTSA look at pedal configuration in heavy vehicles, but the agency has so far declined, records show.

In a sharply worded report to NHTSA last year, the safety board said it was "disappointed" that the issue had not been included in the agency's Nov. 16, 2009, "action plan." The report was classified by the board as "unacceptable."

In a Jan. 11, 2010, letter to the board, Deputy Administrator Ronald L. Medford said the agency had identified other priorities, such as driver fatigue, for their action plan for heavy vehicles but that they would consider interlock and pedal placement recommendations in the future.

Safety board officials said it is unclear whether the report on Toyota vehicles this week might change things.

whoriskeyp@washpost.com kindyk@washpost.com