The world’s largest experiment in driverless cars is underway on the busy streets of Wuhan, a city in central China with 11 million people, 4.5 million cars, eight-lane expressways and towering bridges over the muddy waters of the Yangtze River.

A fleet of 500 taxis navigated by computers, often with no safety drivers in them for backup, buzz around. The company that operates them, tech giant Baidu, said last month that it would add another 1,000 of the so-called robot taxis in Wuhan.

Across China, 16 or more cities have allowed companies to test driverless vehicles on public roads, and at least 19 Chinese automakers and their suppliers are competing to establish global leadership in the field. No other country is moving as aggressively.

The government is providing the companies significant help. In addition to cities designating on-road testing areas for robot taxis, censors are limiting online discussion of safety incidents and crashes to restrain public fears about the nascent technology.

Surveys by J.D. Power, an automotive consulting firm, found that Chinese drivers are more willing than Americans to trust computers to guide their cars.

“I think there’s no need to worry too much about safety — it must have passed safety approval,” said Zhang Ming, the owner of a small grocery store near Wuhan’s Qingchuan Pavilion, where many Baidu robot taxis stop.

Another reason for China’s lead in the development of driverless cars is its strict and ever-tightening control of data. Chinese companies set up crucial research facilities in the United States and Europe and sent the results back home. But any research in China is not allowed to leave the country. As a result, it’s difficult for foreign carmakers to use what they learn in China for cars they sell in other countries.

Then there are the safety issues. As China charges ahead, companies and regulators elsewhere have become more cautious.

The Cruise robot taxi service of General Motors halted service in the United States last fall after one of its cars in San Francisco hit and dragged a pedestrian who had been knocked into its path by a human driver. California regulators later suspended the company’s state license. Cruise has resumed limited testing in Phoenix.

Waymo, formerly Google’s self-driving car division, is testing more than 200 self-driving cars in the Phoenix suburbs and in San Francisco, as well as nearly 50 in Los Angeles and in Austin, Texas. Waymo was notified twice by federal regulators last month that they were reviewing its safety.

Ford and Volkswagen shut down their robot taxi joint venture, Argo AI, two years ago, but both companies are still developing advanced assisted driving systems.

Last fall, Japan suspended its test of driverless golf carts that travel 7 mph after one of them hit the pedal of a parked bicycle. No one was injured. The testing resumed in March.

No company has made bigger bets on computer-guided driving than U.S. automaker Tesla. But its Autopilot system for highway driving, which it introduced in 2014, and its new Full Self-Driving system, for street and highway driving, are not truly driverless. Motorists are required to keep their eyes on the road and hands on the steering wheel.

But Elon Musk, the CEO of Tesla, announced on April 5 a “Tesla Robotaxi unveil on 8/8.”

Many Chinese makers of electric cars are introducing advanced assisted driving features on their mass-production cars.

On June 4, Beijing authorized nine Chinese automakers — including Nio, BYD and SAIC Motor — to begin tests of advanced assisted driving systems that go beyond Tesla’s Full Self-Driving. At least initially, the tests will be done in restricted areas, not on public roads.

Baidu and Huawei, the electronics giant, are supplying part or all of these automated systems to many Chinese automakers. Baidu also has a joint venture with Zhejiang Geely, called Jiyue, to make robot taxis.

The China Society of Automotive Engineers forecasts that 20% of the cars sold in China in 2030 will be completely driverless and that another 70% will have advanced assisted driving technology.

Predicting the future popularity of driverless cars in the United States is difficult because it depends on how quickly carmakers switch to electric vehicles. Driverless technology works much better with battery electric cars than with gasoline-powered cars or most hybrid gasoline-electric cars. Electric motors can increase or decrease power with less of a lag and in more finely controlled increments.

In China, battery electric cars represent about 25% of the market, compared with 7% in the United States.

As with many technologies, including electric car batteries and solar panels, Chinese companies started developing driverless cars by studying American inventions, but then leaped forward in commercializing them. In the years before the COVID-19 pandemic, more than a dozen Chinese firms set up autonomous driving research centers in California, mainly in Silicon Valley. Some, like Baidu, hired hundreds of software engineers. They obtained permission from the California Department of Transportation to test cars on public roads.

These companies moved most of their research to China during the pandemic, when Beijing sealed the country’s borders but allowed key researchers to return. They have continued to work in China.

“If you take California out of the equation, China’s autonomous driving industry would be nowhere near where it is now,” said Michael Dunne, a San Diego automotive consultant who specializes in China.

China has been a big market for Tesla and its advanced assisted driving technologies. But the government is now cracking down on any movement of this data out of China.

Musk visited Beijing in April to seek approval for his company to offer Full Self-Driving in China. He reached deals to keep in China any data gathered in the country, and to obtain high-resolution maps of Chinese roads through an agreement with Baidu.

China does not allow foreign companies to have direct access to high-resolution maps, which are crucial to driverless systems.

Assisted driving or driverless cars use tiny cameras mounted on their exteriors, or in some cases miniature laser systems, to collect information. Most of that data is processed by the car’s computers, which make decisions on steering and vehicle speed.

Although most of the data from cameras and lasers on cars is not uploaded to the carmakers, the potential for tracking people and mapping sensitive locations has troubled security experts.

Europe and the United States still allow manufacturers to send driving data to China, but that may change. U.S. Commerce Secretary Gina Raimondo said last month that the United States would propose rules this fall to regulate cars that were electronically linked to China. Europe has also begun studying the issue.

Baidu believes it has a three- to five-year lead over Tesla in Chinese cities such as Wuhan, according to Wang Yunpeng, president of Baidu’s intelligent driving business group. By operating fully driverless cars in these places, Baidu has learned how the traffic works, block by block, he said in a speech last month.

From steamy coastal ports in southeastern China such as Shenzhen and Fuzhou to metropolises in the mountains of western China, such as Chongqing and Chengdu, cities across China are encouraging broad experimentation.

The New York Times Services