SAN FRANCISCO — San Francisco is trying to curb the spread of robot taxis after repeated incidents in which driverless cars stopped and idled in the middle of the street for no apparent reason, delaying bus passengers and disrupting the work of firefighters.

City transportation officials sent letters this week to California regulators asking them to halt or scale back expansion plans by two companies, Cruise and Waymo, who are competing head-to-head to be the first to offer robotaxi service the 24 hours in the best-known technology center in the country.

The outcome will determine how quickly San Francisco and possibly other cities move forward with driverless technology that could remake the world’s cities and potentially save some of the 40,000 people who die each year in US traffic accidents.

The episode adds another chapter to the complicated history of self-driving cars, an idea that technologists have teased as a future possibility as it has faced a variety of setbacks in recent years. Waymo Deals fully autonomous rides in Phoenix, while Tesla allows some of its owners to try out the «driver assistance» features that are the subject of a federal investigation. An Uber autonomous test vehicle struck and killed a woman in 2018.

Some believe that driverless cars will never happen on a large scale, but have been gaining momentum in San Francisco.

Cruise, majority owned by General Motors, won the permit last year use 30 vehicles as robotaxis in parts of San Francisco between 10 pm and 6 am The vehicles have no backup human drivers during that time. The company has since received permission to test self-driving cars. any time of the daybut you need approval from the California Public Utilities Commission to extend your business service hours.

Neither Cruise’s nor Waymo’s vehicles have killed anyone on the streets of San Francisco, but the companies must overcome their sometimes comical mistakes, including an episode last year in which a Cruise car with no one on board tried to slowly run away from a police officer.

In a recent case documented on social media and noted by city officials, five Cruise vehicles disabled in San Francisco’s Mission District blocked a street so completely that a city bus with 45 passengers could not pass and was delayed for at least 13 minutes. Cruise’s self-driving cars have also interfered with active firefighting, and firefighters once broke a car window to prevent it from running over their hoses, the city said.

San Francisco officials said they want to continue the experiment and even allow Cruise and Waymo to expand, but only if they do so slowly and with conditions.

“A series of limited deployments with incremental expansions, rather than unlimited authorizations, offer the best path to public trust to drive automation and industry success in San Francisco and beyond,” three city officials wrote Thursday in a letter to the public utility commission, the state agency that decides whether a business gets a robotaxi license. A second letter expressed concern for Waymo.

San Francisco doesn’t want robot taxis operating downtown, for example, or during morning and evening rush hours. And he wants more data on the performance of the vehicles.

Last month, the National Highway Traffic Safety Administration he said he was investigating Same problems, including blocked traffic.

Cruise has argued that his service is more secure than the status quo.

«Cruise’s safety record is publicly reported and includes driving millions of miles in an extremely complex urban environment without life-threatening injuries or deaths,» Cruise spokesman Drew Pusateri said in a statement Friday.

He also delivered letters in support of Cruise written by local San Francisco business associations, disability advocates and community groups.

San Francisco is not making progress on its «vision zero» goal of zero traffic deaths by 2024. Last year, there were 37 traffic deaths in the cityan increase from 31 deaths on 2014 when it adopted the goal.

City officials argue that stopped robotic taxis are hazards that can cause human drivers to react dangerously.

“They can cause other vehicles to make sudden and dangerous lane changes, brake or accelerate quickly, or swerve into bike lanes or crosswalks. They can cause rear-end collisions,” they wrote in their letter to the state regulator.

US Transportation Secretary Pete Buttigieg has called the national rise in car fatalities a crisis and all but endorsed a move toward autonomous vehicles.

“Frankly, it would be hard to do worse than human drivers when it comes to what we could theoretically achieve with the right kind of safe autonomous driving.” he told quartz last year.

Waymo, which shares a parent company with Google, tested its technology in San Francisco, but had not done so in vehicles without a safety driver as of last summer, according to the city. As a result, Waymo hasn’t had the same high-profile unplanned shutdowns as Cruise, though it has had difficulty with a dead end street – but the city still wants the company to take it slow on the road to a 24-hour robotaxi service.

Waymo said Friday that it wants to continue talking with the city.

“These letters are a standard part of the regulatory process, and we have long appreciated a healthy dialogue with city officials and government agencies in California,” the company said in a statement, adding that it will craft a filing next week. in writing to regulators. .