Massive Power Outage Knocks Out Much of San Francisco; Disrupts Transit and Self‑Driving Cars

A major power outage struck San Francisco on Saturday, December 20, 2025, leaving roughly 130,000 Pacific Gas & Electric (PG&E) customers — about one‑third of the city — without electricity and triggering significant disruptions across the Bay Area.

The blackout began in the early afternoon and was linked to extensive damage from a fire at a PG&E substation near 8th and Mission streets, although investigators are still examining the exact causes. 

Widespread Impacts Across the City

• Traffic signals failed citywide, forcing drivers to treat dark intersections as four‑way stops and contributing to gridlock in many neighborhoods. AP News
• Public transit was affected, with BART and Muni services disrupted due to the outages. ABC7 San Francisco
• Shops and restaurants closed early or lost business on one of the busiest shopping weekends of the year. ABC7 San Francisco

Autonomous Vehicles Halted
One of the most visible impacts was on Waymo’s autonomous robotaxi fleet. With traffic lights out and signals unavailable, many Waymo vehicles became stalled in intersections with hazard lights flashing, blocking roadways and exacerbating congestion. Slashdot

As a result, Waymo temporarily suspended its ride‑hailing service citywide Saturday evening to ensure rider and public safety while emergency crews worked to restore conditions. SFGATE

The outage highlighted operational challenges for autonomous vehicles dependent on functioning city infrastructure, drawing attention to broader questions about how such technologies respond to major system failures. The Guardian

Restoration Efforts and Current Status
PG&E and city officials continued restoration efforts through Sunday. By early Sunday morning, power had been restored to about 110,000 customers, although tens of thousands remained without electricity as crews worked on complex repairs at the damaged substation. 

City leaders urged residents to limit non‑essential travel, be cautious at inoperative intersections, and minimize power surge risks as electricity steadily returned.

No significant injuries have been reported in connection with the outage so far, and the utility emphasized safety as crews address the damage. Reuters