updated 1/18/2012 5:54:23 PM ET 2012-01-18T22:54:23

A two-year study looking for possible causes behind Toyota’s rash of unintended acceleration issues has put primary blame on driver error — but the review by the National Academy of Sciences also cautioned that some problems may have been caused by inadvertent interactions involving vehicle electronics — an issue frequently cited by the automaker’s critics.

Though there was no hard evidence of specific electronic defects, the 139-page report cautioned that “the absence of evidence is not the evidence of absence.” Warning electronic faults may be “untraceable,” it calls for stricter government involvement in setting standards for the use of electronic control vehicle systems.

The new report completes a series of studies set in motion by the National Highway Traffic Safety Administration which, in March 2010, asked both the NAS’s National Research Council, as well as NASA, to see why there were so many complaints about what the media was referring to as “runaway Toyotas.”

The problem first made headlines in the summer of 2009, when a California Highway Patrol Officer and several members of his family were killed in a fiery crash involving a Lexus they had borrowed. The maker initially recalled several million vehicles due to a problem it described as “carpet entrapment,” but in January 2010 it added millions more due to a potentially sticky accelerator linkage.

Ultimately, more than 8 million Toyota and Lexus vehicles were recalled in the U.S. alone. But the NHTSA received numerous additional complaints — with plaintiffs’ attorneys lining up to file lawsuits against the automaker — alleging some unknown electronic gremlin was also at work.

Last February, the NASA panel issued its report, contending it had found no indication of electronic defects. The National Research Council study echoes that, putting the primary blame on driver error. That had been the conclusion of other investigators in a number of instances — in one, police investigators found that a woman driver involved in a crash had been pressing on the gas pedal, rather than the brake, so hard she had bent its linkage.

Nonetheless, the latest study does not rule out electronic issues, which it cautioned can result in “untraceable faults,” with no physical evidence — other than a crash — to show when there might have been a problem such as a momentary software glitch.

“Some failures of software and other faults in electronics systems do not leave physical evidence of their occurrence, which can complicate assessment of the causes of unusual behaviors in the modern, electronics-intensive automobile,” the report cautioned.

Nonetheless, Louis Lanzerotti, the chairman of the panel and a New Jersey Institute of Technology physics professor, said during a conference call that, “All the data available to us indicated the conclusion that there was no electronic or software problem” that may have caused the Toyota unintended acceleration reports.”

The new study called for a number of steps to be taken to reduce the likelihood that electronic hardware and software do cause problems in the future – a critical issue considering the increasing use of digital technology in modern automobiles. Among the recommendations:

  • NHTSA should convene an advisory panel to set uniform industry testing standards for electronic systems;
  • New vehicles should be equipped with aircraft-style black boxes to make it easier to trace and identify defects;
  • Regulators need to continue research on pedal design and placement.

The study also called for closer cooperation between NHTSA’s researchers and the Transportation Department’s Office of Defect Investigations.

While some critics questioned the latest study — as they did earlier NHTSA and NASA findings, Transportation Secretary Ray LaHood said that in his eyes the latest report “does close the book” on the Toyota scandal.

At one point, following the second unintended acceleration recall, LaHood had said owners of Toyota vehicles involved in the recalls might think about parking those products until they were repaired.

The NHTSA ultimately levied a series of record fines against Toyota, including one for $33 million for delaying action on the sticky accelerator problem.

The maker, long known for seemingly bullet-proof quality, also recalled products in 2009, 2010 and 2011 for a variety of other issues, ranging from electronic brake issues with its Prius hybrid to excessive corrosion that could cause metal parts to fell off while driving the Sienna minivan.

As a result, Toyota had more recalls than any other maker in the U.S. market in 2009 and 2010, and with 3.5 million vehicles involved in service campaigns in 2011, came in just behind Honda, which last year recalled 3.7 million vehicles.

The long-term impact to the company’s reputation is unclear. Toyota — along with Honda — was one of only two major makers to suffer a sales decline in 2011. Analysts put most of the blame on the March earthquake and tsunami that severely limited global production for much of the year, but they also note cool consumer response to the latest update of the Toyota Camry at the same time as competitors like Ford are becoming increasingly aggressive in market segments long dominated by Toyota.

A new study by shows that Toyota has regained its long-standing position as having the highest loyalty rate in the industry. But the maker is still heavily dependent on “conquesting” buyers from other brands. That, many analysts warn, could become more difficult in light of the hits Toyota’s reputation has taken.

More from The Detroit Bureau:

US auto fleet older than ever  
Digital windows on the world?  
Hyundai chief sees slowdown in sales growth  
First Drive: Mazda 2  
Proposed 54.5 mpg standard wins labor, consumer support

Copyright 2012 The Detroit Bureau. All rights reserved.


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