San Francisco faced disruption Saturday night due to a massive power outage that affected daily life across the city. As a result, Waymo temporarily suspended its robotaxi service.
By late Sunday afternoon, Waymo confirmed service had resumed. The incident presented some insight into how autonomous vehicles respond during large-scale infrastructure failures.
San Francisco’s Blackout
The blackout began Saturday evening and was later linked to a fire at a Pacific Gas & Electric substation.
According to reports from SFGate, the outage affected about 120,000 PG&E customers. While most had power restored by late Saturday, the impact lingered.
By Sunday morning, roughly 35,000 customers were still without electricity. PG&E’s website continued to show thousands of customers affected at that time.
The outage knocked out traffic signals across the city. It also disrupted Muni mass transit, and the streets quickly became congested and unpredictable.
San Francisco Mayor Daniel Lurie warned residents to stay off the roads unless travel was necessary. The advisory reflected the scale of the disruption.
Robotaxis Stall
During the blackout, dozens of Waymo robotaxis stopped in place. Many stalled at intersections, while others remained stationary on city streets.
Photos and videos showing Waymo vehicles blocking lanes or waiting at crossings spread rapidly on social media.
And human drivers were seen weaving around the stopped cars or sitting behind them.
Waymo addressed the situation publicly on Saturday. The company said it temporarily suspended service due to the blackout.
Waymo explained that its self-driving systems are designed to treat non-functioning traffic lights as four-way stops. Under normal conditions, this approach works as intended.
However, this outage was unusually large. With so many traffic signals down at once, intersections became difficult to interpret, and traffic flow changed rapidly.
Because of this, some robotaxis remained stationary longer than expected. The vehicles paused to assess conditions before proceeding.
Waymo said the majority of active trips were completed successfully despite the disruption.
Safety Measure
Waymo chose to halt service Saturday evening to limit risk during widespread gridlock.
It was not until late Sunday afternoon that Waymo confirmed service had resumed. A company spokesperson shared a statement with TechCrunch explaining the situation.
The spokesperson said the power outage caused gridlock across San Francisco. Non-functioning traffic signals and transit disruptions contributed to the chaos.
While the failure of utility infrastructure was significant, Waymo said it remains committed to ensuring its technology can adjust to traffic flow during such events.
Lessons Learned
Waymo emphasized that it is reviewing the incident closely. The company said it is focused on rapidly integrating lessons learned from the blackout.
The spokesperson added that Waymo is committed to earning and maintaining the trust of the communities it serves every day.
The Spotlight
The stalling incident follows the event of a leaked letter from Tiger Global Management earlier this month.
The letter revealed that Waymo now provides about 450,000 robotaxi rides per week. That figure is nearly double what the Alphabet-owned company disclosed in the spring.
This mass adoption has implications that call for even closer measures in case the inevitable happens once again.
