A robot car of the General Motors subsidiary Cruise is on a test drive.
Andrej Sokolow | picture alliance | Getty Images

Automotive and tech executives long promised autonomous vehicles would drive better than humans, but that wasn’t the case for a fleet of Cruise cars in San Francisco this week.

The company, a majority-owned subsidiary of General Motors, confirmed it had an “issue earlier this week that caused some of our vehicles to cluster together.” A company spokesman said the problem was “resolved and no passengers were impacted,” but declined to give further details.

Photos and a description of the Cruise robotaxis blocking several lanes of traffic in San Francisco were shared on Reddit and Twitter. At least seven Cruise vehicles can be seen clustering in the intersection of Gough and Fulton streets in the city’s Civic Center neighborhood late Tuesday night, potentially blocking traffic in both ways on one of the streets.

It’s unclear how long the cars were blocking the roads or what caused the situation with the vehicles, which operate with no humans in them aside from paying customers.

The incident is another example of how difficult it is to develop and deploy self-driving vehicle fleets. Commercializing autonomous vehicles has been far more challenging than many predicted even a few years ago. The challenges have led to a consolidation in the autonomous vehicle sector after years of enthusiasm touting the technology as the next multitrillion-dollar market for transportation companies.

The San Francisco Department of Emergency Management was notified and contacted Cruise about the problem, San Francisco Police Department Public Information Officer Kathryn Winters told CNBC. She said no officers were dispatched to the scene.

The incident occurred roughly a week after Cruise became the first company to offer unmanned fared rides to the public in a major city. The vehicles operate between 10 p.m. and 6 a.m. on designated streets. 

Alphabet-backed Waymo has reportedly had similar problems involving clustering of its autonomous vehicles in San Francisco. KPIX-TV, a CBS affiliate in San Francisco, reported in October that Waymo vehicles were getting stuck at a dead-end street in the city.

Cruise’s problem also comes months after an online video of a Cruise autonomous vehicle getting pulled over by police without anyone behind the wheel. In the video posted on April 1, the Cruise car initially pulls over to the side of the road and stops as a cop approached the driver’s side before accelerating to cross an intersection and pull off further down the road.