A lengthy U.S. government investigation into Toyota safety problems has found no electronic flaws that would account for problems with unintended sudden acceleration.
The study, unveiled Tuesday in Washington, was conducted by engineers from the National Highway Traffic Safety Administration and the U.S. space agency, NASA.
Toyota welcomed the findings. In a statement, the automaker said it believed the findings should "reinforce confidence" in the safety of its vehicles, which Toyota said were "well-designed and well-tested" to ensure they did not accelerate accidentally.
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Toyota recalled millions of cars worldwide after reports of vehicles accelerating when their drivers did not want them to do so. Some critics had said the electronics and computers that control many functions in the car might have been to blame.
But the 10-month study says the problems were mechanical rather than electronic. Engineers had said previously that sticking accelerator pedals caused some of the problems, while loose floor mats sometimes accidentally pressed accelerator pedals.
Toyota surpassed General Motors to become the world's largest automaker in 2008, and is projecting increased profits in spite of setbacks caused by the recalls and a rising Japanese yen.