TL;DR
Waymo is deploying software updates across its US robotaxi fleet to reduce disruption when traffic signals fail after a large Pacific Gas & Electric outage in San Francisco last week. The company says changes will give its Driver more regional power-outage context so vehicles can decide more quickly at dark intersections and reduce reliance on HQ confirmation.
What happened
A recent PG&E power failure in San Francisco left many traffic lights disabled and created scenes of stalled Waymo vehicles that paused mid-intersection while awaiting guidance. Waymo says its cars are programmed to treat nonworking signals as four-way stops, but the unusual scale of the outage generated a surge of confirmation requests back to company systems. That spike produced a backlog that, in some cases, kept vehicles stationary longer than intended. The Alphabet-owned service reports its vehicles navigated more than 7,000 dark traffic signals on December 20 and is now pushing a set of updates intended to improve on-road decisiveness. Those updates will supply the Driver with additional context about regional outages to reduce the need for remote confirmation. Waymo also says it will bolster incident preparedness, expand first-responder training, and coordinate with San Francisco officials after the event.
Why it matters
- Autonomous vehicle decision-making can be constrained by centralized confirmation protocols during large infrastructure failures.
- Improving local context awareness in self-driving systems may reduce traffic disruption when signals fail citywide.
- Coordination between AV operators and municipal first responders can affect safety and traffic flow during emergencies.
- Power-grid incidents and weather-related outages continue to present operational risks for connected transportation services.
Key facts
- Waymo is rolling out updates to its US robotaxi fleet to address traffic-signal outages.
- A PG&E substation fire caused a major outage in San Francisco that disabled many traffic lights.
- Waymo vehicles are programmed to treat disabled signals as four-way stops.
- The scale of the outage led to a spike in remote confirmation requests and produced a backlog, causing delays.
- Waymo reported its cars navigated more than 7,000 dark traffic signals on December 20.
- Updates add regional power-outage context to the Driver so vehicles can make more decisive moves at dark intersections.
- Waymo plans to improve incident response and expand first-responder training, working with San Francisco's mayoral office.
- PG&E said the outage affected well over 100,000 customers and was fully restored on Tuesday, according to the company.
- New outages across the area are being attributed to heavy storms, per outage-center updates.
- Hurricane Electric reported a power issue at its Fremont facility but said its network was largely functioning and power was restored.
What to watch next
- Whether the fleet updates reduce intersection delays and remote-confirmation backlogs (not confirmed in the source).
- How expanded first-responder training and city coordination change on-the-ground responses in future outages (not confirmed in the source).
- Ongoing storm-related outages in northern and central California and any further impacts on transportation services.
Quick glossary
- Driver: Waymo's on-board software stack that perceives the environment and makes driving decisions for its autonomous vehicles.
- Four-way stop: A traffic control procedure where vehicles from all directions stop and proceed according to right-of-way rules when signals are out.
- Traffic signal outage: A failure or loss of power to a traffic light that causes it to stop functioning, often requiring alternative right-of-way procedures.
- First responders: Public safety personnel such as police, firefighters, and emergency medical teams who respond to incidents and emergencies.
Reader FAQ
Why did Waymo vehicles stop during the blackout?
Waymo's cars treat disabled signals as four-way stops and, during the outage, a spike in remote confirmation requests created a backlog that delayed some decisions.
What changes is Waymo making?
Waymo is rolling out updates that add regional power-outage context to its Driver to help vehicles make more decisive choices at dark intersections.
How many dark traffic signals did Waymo handle during the incident?
Waymo says its vehicles navigated more than 7,000 dark traffic signals on December 20.
What caused the original PG&E outage?
The outage was caused by a fire at a PG&E substation, according to the company's updates.
Is Waymo working with city officials?
Yes. Waymo said it is coordinating with San Francisco's mayoral office and expanding first-responder training.
AI + ML 2 Waymo pings updates to San Francisco fleet to prevent power outage chaos 2.0 Meanwhile, new outages, linked to storms, are pelting the area Connor Jones Wed 24 Dec 2025…
Sources
Related posts
- Google cuts AI Pro annual price by 50% in limited year-end offer
- Google’s NotebookLM readies ‘Lecture’ mode to expand Audio Overviews
- 6 hidden Google Docs features you didn’t know could save hours