This article is more than 1 year old

San Francisco fog defeats pack of Waymo robo-taxis

Software fix coming – that'll be a braking change we'd actually like to see

A mayhem of self-driving Waymo cars succumbed to San Francisco fog on Tuesday morning and came to a halt, briefly tying up traffic in the city's Balboa Terrace neighborhood.

Five Waymo robo taxis were baffled by Karl – the name by which the American city's frequent fog is known – and pulled over on San Aleso Avenue, according to The San Francisco Chronicle. Human drivers had to find a way to bypass the traffic jam as the idled AI-controlled cars had no human operators fix the issue.

"Around 0600 Pacific Time Tuesday morning, multiple Waymo vehicles in San Francisco encountered very dense fog and determined they should pull over temporarily," a company spokesperson told The Register in an email.

"After a brief stop, the vehicles cleared the area as the fog began to clear. We have software updates planned to improve our fog and parking performance to address such situations in the future."

Earlier this month, rival robo-transit biz Cruise issued a software update of its own after one of its driverless cars failed to handle a slowing bus and smashed into it.

The spontaneous curbside car confab yesterday occurred despite the sensory prowess of Waymo's vehicles. Each is armed with four spinning LiDAR sensors, six radar sensors, fourteen cameras, and eight ultrasonic sensors, and assorted telemetry sensors monitoring the wheels, steering, brakes, and so on.

Back in 2021, Waymo published a blog post about the challenge of driving in San Francisco's fog in which the company celebrates the capabilities of its autonomous driving technology. Even so, the robo-taxi firm admits, "Fog is finicky – it comes in a range of densities, it can be patchy, and can affect a vehicle’s sensors differently."

Waymo, which began as a self-driving car project at Google then became a subsidiary of Google parent Alphabet, has been offering driverless transit to the public in San Francisco since November, with the permission of the California Public Utilities Commission.

In its recent quarterly report to the CPUC, covering the period from December 1, 2022 through February 28, 2023, Waymo says its cars had two collisions and elicited 18 safety complaints, two pick-up/drop-off complaints, one accessibility complaint, two customer service complaints, and six complaints about other things.

A Waymo spokesperson did not immediately respond to a request to provide more details about the company's operations in the city.

Much of the data in the report is redacted. In a letter to state authorities, Waymo deputy general counsel David Tressler said the company has withheld trip-level data (e.g. zip codes of pick-up and drop-off locations), data about Waymo's electric charging infrastructure and sessions, and data about the number of passengers and times of pick-up and drop-off.

Such information, he said, "implicates a protected trade secret or the privacy of Waymo’s riders."

A spokesperson for the San Francisco Municipal Transportation Agency said the SFMTA had no information about the clot of Waymo cars.

"We are currently updating our records on reports we have received from the public and City employees, but the City has no systematic data about road disruption incidents," said Stephen Chun, deputy spokesperson for the SFMTA, in an email to The Register. "No regulatory agency currently requires reporting of data about incidents where driverless AVs have obstructed traffic or created safety hazards.

"We have asked state and federal regulators to collect data so that we can measure the positive and negative effects of AV driving on our streets before they are given permission to expand their operations into peak travel hours when people most need to travel and when our economy and society depend on people's ability to travel."

In "The Halting problem: Video analysis of self-driving cars in traffic," a paper [PDF] to be presented later this month in Hamburg, Germany, at the ACM CHI Conference on Human Factors in Computing Systems, researchers Barry Brown, Mathias Broth, and Erik Vinkhuyzen argue that the challenge presented by Waymo's robo taxis not so much technical as social – how people interact with self-driving cars.

"The introduction of self-driving cars transforms this into a human computer interaction issue – how can self-driving cars interact successfully with other road users," the boffins wrote. "Traffic has become in a sense a new ‘genera’ of human machine interaction – one where there are very long-standing conventions, expectations, and human interactions."

"While the cars we have studied do manage, mostly, to drive and pass through traffic safely, they leave a trail of confusion among other road users, and we must wonder how safe this really is. Confusion about intent, particularly when driving at speed, could easily cascade into collisions or other problems on the road (such as holding up traffic)." ®

More about


Send us news

Other stories you might like