The National Highway Traffic Safety Administration (NHTSA) discovered 9 additional incidents involving Waymo self-driving vehicles, heightening concerns about their performance, according to Reuters. It was reported on May 14th, that the NHTSA is investigating 22 incidents involving Waymo. The agency said several incidents under investigation "involved collisions with clearly visible objects that a competent driver would be expected to avoid." NHTSA has asked Waymo to answer a series of questions by June 11 about the incidents and provide video for all the incidents, the Reuters report added.