U.S. auto safety officials said on Thursday they are investigating two additional reports of General Motors (GM.N) Cruise self-driving cars engaging in inappropriately hard braking that resulted in collisions.
The National Highway Traffic Safety Administration (NHTSA) said in December it had opened a formal safety probe into the GM robotaxi unit Cruise after reports of three crashes in which Cruise vehicles were struck from behind by other vehicles after the autonomous vehicles braked quickly, resulting in two injuries.
NHTSA said in an Oct. 20 letter made public Thursday it had two additional crash reports involving Cruise vehicles that braked with no obstacles ahead and is seeking additional information by Nov. 3.
"Inappropriately hard braking results in the Cruise vehicles becoming unexpected roadway obstacles and may result in a collision with a Cruise vehicle," NHTSA said in its letter.
Cruise said it continues to cooperate with the ongoing investigation.
“We welcome NHTSA’s questions related to our safety record and operations," Cruise said.
California's Department of Motor Vehicles (DMV) suspended Cruise's autonomous vehicle deployment and driverless testing permit and the company said it would comply. The DMV in August had directed Cruise to remove half of its driverless vehicles after another crash.
"Based upon the performance of the vehicles, the department determines the manufacturer's vehicles are not safe for the public's operation," the DMV said in a statement.
Cruise said the DMV was reviewing an Oct. 2 incident where one of its self-driving vehicles braked but did not avoid striking a pedestrian who had previously been struck by a hit-and-run driver.
The DMV order said Cruise had not initially disclosed all video footage of the accident and said "Cruise's vehicles may lack the ability to respond in a safe and appropriate manner during incidents involving a pedestrian."
