美国（机动车监管）部门结束针对谷歌母公司Alphabet旗下无人驾驶部门Waymo自动驾驶汽车碰撞事故和马斯克旗下特斯拉RoboTaxi意外事故的调查。此前，（两家涉事公司）实施了两次召回。

Core Viewpoint - The U.S. vehicle regulatory agency has concluded investigations into collision incidents involving Waymo, a subsidiary of Alphabet, and Tesla's RoboTaxi accidents, following two recalls by the companies [1] Group 1 - The investigations focused on autonomous vehicle accidents involving Waymo and Tesla [1] - Both companies had previously implemented two recalls related to the incidents [1]