A massive power outage Saturday darkened 130,000 homes and businesses in San Francisco, according to the city’s main utility firm, Pacific Gas and Electric (PG&E).
Self-driving cars stalled in streets and blocked access points across the metropolis as just part of the stoppage. The autonomous vehicles were reportedly unable to detect down traffic lights, triggering traffic jams across affected areas.
The power failure left a large swath of the northern part of the city in the dark, beginning with the Richmond and Presidio neighborhoods and areas around Golden Gate Park in the early afternoon before growing in scope and size, the Independent reports.
The widespread blackout, caused by a fire at a PG&E substation near 8th and Mission Streets, left roughly 30 percent of the city without electricity.
A view of traffic from above as more than 130,000 PG&E customers without power in San Francisco, California, United States on December 20, 2025. Traffic jammed the streets as a result as autonomous vehicles ground to a halt. (Photo by Tayfun Coskun/Anadolu via Getty Images)
The outage, which began in the morning and continued into the evening, hit areas including Richmond, Sunset, Haight‑Ashbury, Pacific Heights, and the Presidio, cutting power to stoplights and public transit systems.
Social media posts and local media confirmed mass closures of restaurants and shops and darkened street lights and Christmas decorations.
The San Francisco Department of Emergency Management said on X there were “significant transit disruptions” happening citywide and urged residents to avoid nonessential travel and treat down traffic signals as four-way stops.
Waymo driverless car is not able to detect traffic lights after a major power outage in San Francisco, California, United States on December 20, 2025. (Photo by Tayfun Coskun/Anadolu via Getty Images)
AP reports the city’s transportation agencies said they were bypassing some Muni bus and BART train stations because of the power outages.
At about 4 p.m., PG&E posted on X that it had stabilized the power grid and was not expecting additional customer outages.