U.S. safety regulators are standing by their initial assessment that sticky pedals caused Toyota Motor Corp. cars to unintentionally accelerate, in response to an inquiry by Sen. Charles Grassley, R-Iowa. The regulators are denying the possibility that it was an electrical issue.
The National Highway Traffic Safety Administration sent a letter to Grassley, saying that it had meticulously studied the effects of what’s known as tin whiskers, a crystalline growth on a metallic surface that may cause electrical interference with the pedal. It didn’t’ find any evidence that it had led to the unintentional acceleration cases. The NHTSA said that "pedal misapplication” is the probable cause.
In response to what Grassley asked, the agency wrote that he doesn’t think that tin whiskers would be a possible explanation for these incidents. Grassley, the ranking member of the Senate Judiciary Committee, said that whistleblowers had provided documents from the NHTSA's joint investigation into the Toyota issue, which resulted to the recall of millions of vehicles around the world.
He said that there were concerns that the regulators' probe was "too narrow" in scope. The NHTSA and NASA conducted the investigation for 10 months and they didn’t find any electronic defect in Toyota’s vehicles.
These agencies put the blame on pedals that could get stuck or caught under floor mats. In NHTSA’s response, it reaffirmed its ruling, saying that there were few incidents wherein tin whiskers may have resulted to a "jumpy" throttle. Not one had resulted to sustained or unsafe acceleration. The condition halted as soon as the driver released the pedal. [source: Automotive News - sub. required]