GM's Cruise updates software, recalls 300 self-driving vehicles for crash risk

WASHINGTON — General Motors' self-driving unit Cruise LLC recalled 300 robotaxis and updated their software after a March 23 crash with a San Francisco bus.

In a document submitted Monday to NHTSA, Cruise said the collision was caused by "an issue related to prediction of the unique movements of articulated vehicles," such as buses and tractor trailers.

In the San Francisco incident, Cruise said its robotaxi initially perceived both sections of the bus as it was pulling out of a bus stop. As the bus proceeded forward into the Cruise robotaxi's lane, the rear section of the bus blocked the front section, and the bus began decelerating.

Cruise told federal regulators that its vehicle "inaccurately determined that the bus was continuing to move forward in traffic based on the anticipated behavior of the front section of the bus, which was by then obstructed, and the [automated driving system] commanded the [autonomous vehicle] to begin decelerating too late to avoid a rear-end collision with the bus."

Cruise said it notified NHTSA the following day in accordance with the agency's crash-report mandate and implemented the software update March 25.

No other collisions have occurred as a result of the software issue, according to the report.

In a blog post Thursday, Cruise CEO Kyle Vogt detailed the bus collision, stating that "it resulted in minor damage to the front fender of the AV and caused no injuries."

"Fender benders like this rarely happen to our AVs, but this incident was unique," he wrote. "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."

In December, NHTSA opened a safety probe into Cruise's automated driving system to assess incidents where the robotaxis might "engage in inappropriately hard braking or become immobilized."

The investigation comes after reports of three crashes in which Cruise self-driving vehicles were struck from behind by other cars after braking quickly.

Cruise is offering limited-service driverless rides in San Francisco, Phoenix and Austin, Texas.

NHTSA did not immediately respond to a request for comment.

Reuters contributed to this report.