Federal regulators uncovered stark evidence that some Toyota cars accelerated unexpectedly more than two years ago. But neither the government's safety agency nor the automaker apparently recognized at the time how broad the dangers would turn out to be.
During a little-noticed 2007 inquiry, investigators found that at least three of every 100 Lexus ES 350 owners in Ohio reported experiencing unintended acceleration, an unacceptably high percentage given the potentially fatal consequences, industry experts said.
"Anything over 1 percent would raise a red flag, particularly for the manufacturer," said James C. Fell, who worked at the National Highway Traffic Safety Administration for 30 years, and was chief of research for traffic safety programs.
The investigation opened formally in August 2007, one of the few times NHTSA commenced a full-fledged investigation into reports of Toyotas accelerating unexpectedly. More often, the inquiries have ended at the "preliminary evaluation" stage, meaning investigators reviewed the reports but didn't venture into engineering analysis. In this case, they acquired a Lexus ES 350 and attached instruments to it to monitor the operation of its accelerator and brake pedal. The investigators also exposed the accelerator system to magnetic fields.
In addition, investigators gathered accounts of drivers crashing in cars that sped out of control. Among those interviewed was a 70-year-old Illinois woman who was taken on a two-mile ride at 60 miles per hour before she collided with another vehicle in an intersection.
But agency officials only partially identified the cause of the problem and, moreover, concluded it affected a limited number of cars.
Reputation under assault
This week, as the automaker found its reputation for quality and reliability under assault, a reading of the Lexus inquiry raises questions about why the automaker and the safety agency failed to prevent the problem from causing the current furor.
Officials now seem intent on leaving no stone unturned, taking pains to err on the side of caution. On Wednesday, Transportation Secretary Ray LaHood he would urge Toyota owners to stop driving recalled vehicles immediately. He later backed off his remarks, but shares of Toyota plunged by more than 7 percent in the moments following the reporting of his statements.
Japanese officials, meanwhile, have directed Toyota to investigate the 2010 Prius braking system while their U.S. counterparts said they will conduct their own probe of the Prius's brakes. Of 171 complaints filed by 2010 Prius owners with the NHTSA, 111 involved brake problems, the agency's database shows, and at least two led to driver injuries.
Toyota representatives did not respond to a request for comment Wednesday.
If anything was learned from the 2007 inquiry, those lessons have not gotten the company very far, for Toyota today seems to be wrangling with the same issue: What exactly is causing the problem?
Last fall, Toyota announced that it had resolved the problem by issuing a recall of floor mats. The mats, the company said, sometimes trapped the accelerator in the depressed position.
Then in recent weeks, it announced that it had identified another cause — sticking accelerator pedals. Millions more vehicles were recalled.
The shifting diagnoses have left members of Congress and some auto safety experts questioning whether the company has fully identified the causes of the unintended acceleration incidents.
The 2007 inquiry suggests that identifying the root cause can be difficult.
As the investigation got underway, the safety agency had fielded 26 complaints about the Lexus and the Toyota Camry, according to agency records. Toyota, when asked, reported another 31.
The trouble with such complaints, at least from a research point of view, is that the group of people complaining may not represent the owners as a whole. A complaint can stem from a real problem, or perhaps the driver has a grudge against the company or may simply be trying to blame bad driving on the car.
So in addition to acquiring and testing a vehicle, the investigators decided to conduct a survey. As the investigation evolved, the focus narrowed to the 2007 Lexus ES 350.
It sent 1,986 surveys to registered owners of the cars, a group that encompassed the entire list of such owners in the state of Ohio, according to the agency.
The agency received back 600 responses. Of those, 59 said they had experienced episodes of unintended acceleration.
'Incredibly high percentage'
The figure represents 3 percent of the total population of Ohio Lexus 350 owners, and 10 percent of those who responded to the survey.
"That's an incredibly high percentage," said Clarence Ditlow, director of the Center for Auto Safety.
After the engineering review, Toyota and the regulators decided that the cause was that the accelerator had been stuck in the grooves of the all-weather floor mats some owners had put in. It was shown that the floor mats could trap the accelerator.
So the company declared a recall of approximately 55,000 such floor mats and the case was closed.
But for some consumers, the mystery remained.
Twenty-four of the 59 owners who reported acceleration episodes in the survey did not report having the floor mats: What caused the problem?
The investigation didn't speculate.
"It's hard to believe that a company with the reputation for engineering excellence that Toyota enjoys doesn't know what is going on. But if they do, they haven't shared what they know," Ditlow said.