Tech company Waymo is making changes after its self-driving taxis blocked intersections and snarled traffic during the San Francisco power outage on Saturday. The company says it’s updating its software so the robotaxis can “navigate more decisively” in a power failure.

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

The incident has prompted renewed questions about how autonomous vehicles perform during large-scale emergencies.

The self-driving car startup owned by Google parent Alphabet will update its software fleetwide to improve navigation during power outages after vehicles froze in San Francisco.

Waymo says it will implement a fleet-wide update to help its cars make safer, quicker decisions during power outage incidents like the one in San Fran.

A top California regulator said it was looking into incidents in which robotaxis from Alphabet unit Waymo stalled in parts of San Francisco on Saturday due to a widespread power outage that snarled traffic and gridlocked parts of the city.

City officials have called for a hearing investigating Waymo after the company’s self-driving taxis suffered widespread problems during a power outage.

The California Public Utilities Commission is looking into Waymo vehicles that stalled on Saturday during a San Francisco power outage.