The National Academy of Sciences will lead a broad investigation into unintended acceleration and electronic vehicle controls under a 15-month study made public Tuesday.
In addition, the National Highway Traffic Safety Administration will conduct a separate inquiry into sudden acceleration by Toyota Motor Corp. vehicles. Toyota has issued nearly 10 million recall notices worldwide to correct floor mat and gas pedal defects that it says can lead to runaway vehicles.
The two investigations follow pressure from Congress on federal safety regulators to address persistent questions about the causes of unintended acceleration, and whether the problems stem from faulty computer-controlled electronic throttle systems.
At a time when cars are increasingly controlled through complex computer systems, the studies represent the most far-reaching effort yet to assess the causes of sudden acceleration.
"We are determined to get to the bottom of sudden acceleration," Transportation Secretary Ray LaHood said in a news release dated Tuesday. "For the safety of the American driving public, we must do everything possible to understand what is happening."
LaHood also said he had asked his department's inspector general to assess whether federal safety regulators dropped the ball over the last eight years in reviewing thousands of motorist complaints about sudden acceleration.
The two studies are expected to cost about $3 million combined.
In recent congressional hearings, the performance of those regulators came under severe criticism, based on concerns that they lacked expertise to examine automobile electronics and depended too much on the industry to police itself.