A large power outage knocked out electricity for roughly 130,000 homes and businesses in San Francisco on Saturday, leaving parts of the city in the dark and causing major transportation disruptions. The outage also affected autonomous vehicles, with reports of self-driving cars stopping in the street as traffic lights went dark.
Pacific Gas and Electric Co. (PG&E) did not immediately identify a single cause for the blackout. However, San Francisco fire officials said at least some of the outage was linked to a fire at a PG&E substation near 8th and Mission streets, according to posts shared on social media.
The incident underscores how modern cities depend on electricity not just for lights and appliances, but also for signals, transit coordination, and emerging services like driverless ride-hailing.
What happened during the outage
Reports indicated the outage began in the afternoon and spread across large areas. Fox News reported that it affected wide swaths of the city’s north side, starting in neighborhoods including the Richmond and Presidio, as well as areas around Golden Gate Park, before expanding further.
As the blackout grew, it created immediate challenges for drivers, pedestrians, and public transportation. When traffic signals shut off, intersections can turn into confusion points, especially in busy corridors. City officials urged residents to avoid nonessential travel and to treat dark intersections as four-way stops.
Transit disruptions and public safety guidance
The San Francisco Department of Emergency Management said there were “significant transit disruptions” occurring citywide. During an outage, transit impacts can include stalled signals, delays tied to rerouted traffic, and interruptions at stations or stops that rely on grid power.
Emergency guidance focused on limiting travel, slowing down at intersections, and using caution in areas where street lighting was out. In a dense city, a power outage can also affect elevators, building access systems, and communication infrastructure, which can complicate routine movement for residents and visitors.
For many people, the most practical immediate problem is visibility and traffic control. When signals fail, drivers often hesitate or inch forward at the same time, which increases the odds of gridlock or minor collisions. That risk becomes even more serious if fog or rain reduces visibility further.
Why autonomous vehicles were impacted
One of the most striking side effects was the impact on self-driving vehicles. Fox News reported that autonomous cars stalled in the middle of streets, with accounts suggesting the vehicles had difficulty operating when traffic lights were down. The stalled vehicles reportedly contributed to traffic jams in affected areas.
Autonomous vehicles use cameras, radar, and other sensors to interpret the road. Many systems can handle intersections without signals, but dark traffic lights can still create edge cases that trigger extra caution. In some situations, a driverless system may decide the safest option is to slow down, stop, or pull over until conditions become clearer.
While that may be a conservative safety choice, it can create real challenges if many vehicles do the same thing in a busy area at once.
Waymo reportedly pauses service
Fox News also reported that Waymo temporarily suspended its autonomous ride-hailing service in response to the outage, citing SFGate. Fox News Digital said it reached out to Waymo for comment but did not immediately receive a response.
A temporary suspension is not unusual during abnormal citywide conditions. For any transportation provider, safety and predictability matter. If traffic signals are down across multiple neighborhoods, it becomes harder to guarantee consistent performance for riders and other road users.
This also highlights a key operational reality of driverless systems: even if vehicles are autonomous, they still depend on stable city infrastructure. That includes power to traffic signals, reliable mapping conditions, and communication networks that support monitoring and incident response.
What caused the outage?
PG&E did not immediately provide a detailed explanation for the outage. However, the San Francisco Fire Department indicated that at least some of the blackouts were caused by a fire inside a PG&E substation at 8th and Mission streets.
Substations are critical nodes in the electrical grid. A failure or fire can lead to protective shutdowns that cut power to large areas. When that happens in a compact city, the ripple effects can be widespread and immediate.
Restoration update: power returns to many, thousands still without electricity
Later Saturday night, PG&E provided a restoration update. Fox News reported that by about 11:30 p.m., power had been restored to roughly 95,000 customers, with about 35,000 customers still without electricity. PG&E said crews would continue working through the night to restore service.
In large outages, restoration often happens in stages. Utilities typically focus first on safety, isolating damaged equipment, and then restoring power to the largest number of customers as quickly as possible. Some smaller pockets may take longer, especially if repairs require specialized equipment or if a site is unsafe to access.
What residents can do during a major city outage
If you are in an affected area, basic steps can reduce risk and stress:
- Limit travel, especially through neighborhoods with dark signals and heavy traffic.
- Use caution at intersections. Treat non-working signals as four-way stops.
- Keep phones charged when possible and use flashlights after dark.
- Check utility updates for restoration estimates and safety notices.
- Be mindful of elevators and building access systems that may not work.
Saturday’s outage showed how quickly a power failure can disrupt daily life in San Francisco, from transit delays to traffic control problems. It also exposed a modern vulnerability: connected transportation services, including autonomous ride-hailing, can be forced to pause when core infrastructure like traffic signals goes dark.
Source: This article is based on reporting published by Fox News. Original story: San Francisco power outage hits 130,000 homes and businesses. The Associated Press contributed to the original report, per Fox News.
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