Toyota Motor Corp. defended its Toyota and Lexus vehicles and the validity of prior investigations.
Whatever the cause, Toyota and Lexus owners have grappled with the dangerous consequences.
* Jean Bookout awoke in an Oklahoma hospital a month after a crash in her 2005 Camry.
She said the car sped out of control on a freeway, then smashed into an embankment after she swerved it onto an exit ramp, leaving behind long skid marks from attempts to stop the vehicle with her brakes and emergency brake.
Bookout sustained permanent memory loss, and her best friend died.
"I did everything I could to stop the car," she said Tuesday.
* Nancy Bernstein, a vice president for a Long Beach community garden and former science teacher, said she was taken on an 8-mile high-speed ride by her 2007 Prius while she was following her husband in a group bicycle tour in Wisconsin. She said her Prius accelerated from 45 mph to 75 mph on a winding, two-lane highway crowded with 100 cyclists.
"I was sure I was going to kill someone on a bicycle or myself," she recalled. "I stood on the brakes with both feet. All of a sudden, I see fire. I thought, sure, my brakes are on fire. I thought about maybe trying to sideswipe a tree to slow down."
Eventually she was able to stop at the bottom of a hill, using her brakes and emergency brake. A local resident rushed out with a fire extinguisher.
* Dr. David. W. Smith, an emergency room physician from San Dimas, has yet to receive a satisfactory answer from Toyota about his Lexus GS 300. Smith said he was driving with his cruise control in Central California on Highway 99 last year, not touching the accelerator, when suddenly the vehicle accelerated to 100 mph.
The brakes did not release the cruise control or slow down the vehicle, Smith recalled. Finally, he shifted into neutral and shut off the engine. "I am sure it is the cruise control," he said. "I haven't used it since."
In reviewing consumer complaints during its investigations, the NHTSA relied on established "positions" that defined how the agency viewed the causes of sudden acceleration. Cases in which consumers alleged that the brakes did not stop a car were discarded, for example, because the agency's official position was that a braking system would always overcome an engine and stop a car. The decision was laid out in a March 2004 memorandum.
When asked to submit its own complaint data to the NHTSA, Toyota eliminated reports claiming that sudden acceleration occurred for "a long duration," or more than a few seconds. Elsewhere, the company said a fail-safe in its throttle system makes such an event impossible.
NHTSA officials acknowledged in a statement that the exclusions were made, but defended the practice.
"While some vehicles may be excluded from the scope of an investigation into a specific defect allegation, all are continuously reviewed, along with other relevant information, in order to identify other emerging issues of concern," the statement said.
A reduced pool of reports created the appearance that the problem was much smaller than the total number of complaints suggested, making a broader vehicle recall seem less necessary, critics say.
"NHTSA has ways of pigeonholing reports, categorizing them as brake failure rather than sudden acceleration," said attorney Edgar Heiskell of Charleston, W.Va., who is suing Toyota over a fatal crash in Flint, Mich. "By excluding these braking and long-duration events, they have taken 80% of the cases off the table."
In 2004, the NHTSA began a probe into a defect petition filed by Carol J. Mathews, a registered nurse who was then director of health services for the Montgomery County, Md., school system. Matthews reported that she had her foot on the brake of her 2002 Lexus ES when it took off and hit a tree.