By David Shepardson
WASHINGTON, Dec 23 (Reuters) - Alphabet unit Waymo said on Tuesday it will update software used to operate its self-driving vehicles and improve its emergency response protocols after its robotaxis stalled in parts of San Francisco on Saturday due to a widespread power outage that snarled traffic and gridlocked parts of the city.
Waymo paused service Saturday evening following a fire at a PG&E substation that knocked out power to roughly one-third of the city, affecting about 130,000
residents and forcing some businesses to close temporarily.
A number of videos posted on social media showed Waymo robotaxis stuck at intersections with their hazard lights turned on as traffic lights stopped working due to the outage.
Waymo said its self-driving vehicles are designed to handle dark traffic signals at four-way stops but they may occasionally request a confirmation check.
"While we successfully traversed more than 7,000 dark signals on Saturday, the outage created a concentrated spike in these requests," Waymo said. "This created a backlog that, in some cases, led to response delays contributing to congestion on already-overwhelmed streets."
Waymo said the confirmation protocols made sense during early deployment but it is now refining them to match the company's current scale. Waymo is implementing fleet-wide updates that provide vehicles with "specific power outage context, allowing it to navigate more decisively."
Waymo also said it would improve its emergency response protocols by incorporating lessons from this event.
Waymo, which has a fleet of more than 2,500 vehicles operating in the Bay Area, Los Angeles, Metro Phoenix, Arizona, Austin, Texas and Atlanta, Georgia, said it resumed its ride-hailing service in the San Francisco Bay Area on Sunday.
On Monday, the California Public Utilities Commission (CPUC) said it was reviewing the issue of stalled Waymo vehicles. The CPUC, along with California's Department of Motor Vehicles, regulates and issues permits for testing and commercial deployment of robotaxis.
Earlier this month, Waymo issued a recall to update the software for its self-driving cars after officials in Texas said the vehicles illegally passed school buses at least 19 times since the start of the school year. That prompted the National Highway Traffic Safety Administration to open a probe into the issue in October.
(Reporting by David Shepardson and Kanishka Singh in Washington; Editing by Christian Schmollinger)
