The U.S. Transportation Department's final report on Toyota Motor Corp.'s sudden acceleration cases may be a relief to Toyota but experts say it won't be easy for the world's No. 1 automaker to regain lost ground in the United States amid intensifying competition.

The department announced Tuesday in Washington that its investigation — assisted by NASA engineers — resulted in the finding of no electronic flaws to account for reports of unintended acceleration and other safety problems.

"Toyota avoided the worst possible scenario," said Yasuo Tsuchiya, an expert on the automobile industry and vice chairman of the nonprofit Japan Think Tank Academy.