WASHINGTON (Reuters) – U.S. auto safety officials are investigating two more reports of General Motors’ robotaxi unit, Cruise, experiencing inappropriately hard braking and being hit by other vehicles during self-driving operations. The National Highway Traffic Safety Administration (NHTSA) announced in December its formal safety probe into Cruise, following three previous incidents in which other vehicles struck the autonomous vehicles from behind after they braked abruptly, injuring two people. On October 20, NHTSA publicized a letter revealing two additional crash reports involving Cruise vehicles that braked suddenly “with no stated obstacles ahead.” NHTSA is requesting further information by November 3. (Reporting by David Shepardson; Editing by Chris Reese)