California regulators investigate Waymo's driverless taxi service shutdown.

California regulators are investigating the suspension of Waymo's self-driving taxi service in parts of San Francisco. Waymo suspended service on December 20 due to a fire at a Pacific Gas and Electric Company (PG&E) substation that caused a power outage in parts of the city. Videos on social media showed Waymo taxis stuck at intersections. This incident highlights the unforeseen circumstances that autonomous vehicle operators may encounter as they race to deploy self-driving taxis in the United States.