Waymo plans software updates after power outage stalls robotaxis

Alphabet (GOOGL) unit Waymo said it will update software and revise emergency response protocols after a widespread power outage caused its self-driving vehicles to stall in parts of San Francisco.

The incident occurred Saturday evening after a fire at a Pacific Gas and Electric Company substation cut electricity to roughly one-third of the city. About 130,000 residents were affected, and some businesses temporarily closed.

Waymo paused service that night as traffic signals went dark across large areas of the city. Videos posted on social media showed robotaxis stopped at intersections with hazard lights flashing while surrounding traffic backed up.

The company said its vehicles are designed to navigate intersections when signals are dark by treating them as four-way stops. In some situations, the system requests a confirmation check before proceeding.

Waymo said the outage created an unusually high concentration of those requests at the same time. The surge overwhelmed response capacity and led to delays that contributed to congestion on already crowded streets.

The company said its vehicles successfully crossed more than 7,000 dark intersections during the outage. However, the spike in requests revealed limits in procedures that were designed earlier in the deployment.

Waymo said it is refining those protocols to better reflect the current size of its operations. It is rolling out fleet-wide software updates that give vehicles specific power outage context so they can navigate more decisively.

The company also said it will incorporate lessons from the incident into its emergency response plans. Service in the San Francisco Bay Area resumed on Sunday.

Waymo operates more than 2,500 vehicles across the Bay Area, Los Angeles, Metro Phoenix, Austin and Atlanta. The vehicles are used in commercial ride-hailing services and testing programs.

On Monday, the California Public Utilities Commission said it was reviewing the stalled vehicles. The commission and the state Department of Motor Vehicles oversee permits for testing and commercial robotaxi deployment.

Earlier this month, Waymo issued a recall to update software after officials in Texas said its vehicles illegally passed school buses at least 19 times. That issue led the National Highway Traffic Safety Administration to open a probe in October.