By David Shepardson
WASHINGTON (Reuters) -General Motors' robotaxi unit Cruise LLC is recalling the automated driving software in 300 vehicles after one of its driverless vehicles crashed into the back of a San Francisco bus.
The March 23 collision was the fault of a software error in a Cruise automated vehicle (AV) that inaccurately predicted the movement of an articulated San Francisco Municipal Transit Authority bus, Cruise said on Friday. The crash caused moderate damage to the Cruise but did not result in any injuries.
Cruise in a National Highway Traffic Safety Administration (NHTSA) filing on Friday said the software was updated on March 25 to address concerns that the system "may inaccurately predict the movement of articulated vehicles such as buses and tractor trailers."
"Fender benders like this rarely happen to our AVs, but this incident was unique," Cruise CEO Kyle Vogt said in a blog post. "We do not expect our vehicles to run into the back of a city bus under any conditions, so even a single incident like this was worthy of immediate and careful study."
Cruise in a separate filing with California said the vehicle was traveling on Haight Street when a bus stopped ahead of it and the Cruise struck the rear bumper.
Vogt said, "The bus’s behavior was reasonable and predictable. It pulled out into a lane of traffic from a bus stop and then came to a stop. Although our car did brake in response, it applied the brakes too late and rear-ended the bus at about 10 mph."
The driverless vehicle's view of the bus’s front section became fully blocked as the bus pulled out in front of the AV.
"Since the AV had previously seen the front section and recognized that the bus could bend, it predicted that the bus would move as connected sections with the rear section following the predicted path of the front section," Vogt said, adding that it was the only crash of its kind that the company has experienced.
Cruise said after the update it determined the crash would not recur.
Cruise in September disclosed that it recalled and updated software in 80 self-driving vehicles after a June crash in San Francisco that left two people injured.
NHTSA last year said the software could "incorrectly predict" an oncoming vehicle's path.
NHTSA in December opened a formal safety probe into the Cruise autonomous driving system after it received reports of incidents in which self-driving Cruise vehicles "may engage in inappropriately hard braking or become immobilized."