San Francisco was plunged into darkness after a massive power outage cut electricity to nearly 30 percent of the city, leaving more than 130,000 homes and businesses without power and disrupting critical transportation systems, including self-driving vehicles.

The outage struck Saturday night and heavily impacted the city’s northwest neighborhoods, including the Richmond, Sunset, Presidio, and areas surrounding Golden Gate Park. Residents reported sudden blackouts, stalled traffic systems, and autonomous vehicles coming to an abrupt halt as power-dependent infrastructure failed.

Officials confirmed that the blackout affected both residential and commercial areas, raising concerns about the city’s reliance on advanced technology amid basic infrastructure vulnerabilities. Self-driving cars, which require constant communication with traffic systems and sensors, were forced offline, underscoring the fragility of so-called “smart city” transportation during grid failures.

Emergency crews were deployed to manage traffic, assist residents, and begin restoration efforts. Authorities urged caution as darkened intersections and disabled transit systems posed safety risks throughout the affected areas.

The incident has renewed scrutiny of California’s energy infrastructure, particularly in major urban centers that increasingly depend on electrified and automated systems. As restoration efforts continued, the outage served as a stark reminder that even one of America’s most technologically advanced cities remains vulnerable to large-scale grid disruptions.