Overview
- A Dec. 20 PG&E substation fire cut power to roughly one-third of San Francisco, leaving traffic lights dark and Waymo robotaxis stalled at intersections before service was halted and then restored the next day.
- Waymo said its vehicles treat dark signals as four-way stops but sometimes require human confirmation, and a surge in those requests during the outage caused response delays that worsened congestion.
- The company reported its cars successfully navigated more than 7,000 dark signals during the event while it worked to manage the spike in remote-assistance confirmations.
- Waymo is deploying fleet-wide software updates to give vehicles specific power-outage context and is refining confirmation processes to better match current scale.
- The California DMV and CPUC are investigating the incident, and days later Waymo paused Bay Area rides again due to a National Weather Service flash flood warning, notifying riders in its app.