Three days following a massive San Francisco blackout that disrupted its driverless operations, Waymo said it will upgrade its fleet to better handle future power outages.

As power outages spread Saturday, videos shared on social media appeared to show multiple Waymo vehicles stalled in traffic in different parts of San Francisco.

On Sunday, the Waymo app showed a notification to some customers saying the service for the Bay Area is paused, affecting at least seven cities.