Waymo says the San Francisco power outage overwhelmed its robotaxis at scale, creating a backlog that led to response delays.

Waymo is shipping a software update to help its robotaxis navigate disabled traffic lights during power outages “more decisively,” the company said Tuesday in a blog post that explains why its self-driving vehicles got stuck at intersections during a blackout in San Francisco this past weekend.

After widespread power outages in San Francisco overwhelmed Waymo’s remote assistance system, the company is rolling out a software update to help its driverless cars better manage large-scale blackouts.

A major power outage in San Francisco turned Waymo’s driverless fleet into rolling roadblocks, as the company’s autonomous cars encountered dark intersections, stopped, and then mostly refused to move.

Waymo's fleet of Jaguar I-Pace-based robotaxis experienced a widespread shutdown during a recent major power outage in San Francisco, leaving multiple vehicles stalled and blocking roads. The incident has raised questions about the autonomous cars' ability to handle unexpected disruptions,

Waymo is rolling out a fleet-wide software update after a massive San Francisco power outage exposed a critical bottleneck in its autonomous system — forcing the Alphabet-owned company to halt robotaxi service as driverless cars stalled at darkened intersections across the city.

Here's why Waymo robotaxis freaked out during a massive San Francisco power outage, and how the company hopes to prevent a similar situation in the future.

Severe weather warnings were in effect for the Bay Area over Christmas Day. The Waymo service disruptions comes just a few days after the Alphabet-owned company said it would update its fleet to better operate during power outages Waymo again paused its driverless taxi service in San Francisco citing flash flood warnings.