A widespread power outage in San Francisco caused by a substation fire left more than 100,000 homes and businesses without electricity and disrupted traffic signals across the city. The blackout also forced Waymo to suspend its self-driving taxi service after vehicles became overly cautious at signal-free intersections and struggled with unpredictable pedestrian behavior, according to Brendan McAleer of Car and Driver. While Waymo vehicles are designed to treat dark intersections as four-way stops, the scale of the outage overwhelmed their systems, prompting the company to pull the fleet from service until power was restored. McAleer writes:
This past weekend, vast blackouts plunged much of San Francisco into darkness. Suddenly, a city that prides itself on its technology centers couldn’t even get a light bulb to work. The problem stemmed from a fire at a substation, which affected more than 100,000 homes and businesses. It also affected the Waymo self-driving taxi network.
With mass outages for traffic signals, the self-driving taxis began shutting down, stopping at intersections. Eventually, Waymo shut down the taxis entirely, pulling them out of service until Sunday afternoon. […]
When approaching a four-way intersection where the lights have gone down, the cars’ software treats it as a four-way stop, just as a conscientious driver should do. […]
The problem seems to have been two-fold. On one hand, the massive scale of the blackout caused the Waymo taxis to pause much longer than usual at uncontrolled intersections. Further, with a lack of traffic signals, pedestrians were more prone to cross at random. Waymo taxis’ onboard software seems to have been overwhelmed by all the variables. […]
However, it might also be a good idea for them to be programmed to pull to the curb rather than blocking traffic when overwhelmed by information. Still, Waymo engineers will be taking a good look at what went wrong and coming up with contingency plans for the future.
Read more here.