Two companies developing self-driving cars in China were given permission last week to remove the safety driver from behind the steering wheel for the first time.

The permission was granted by officials in Beijing to technology giant Baidu and Toyota-backed self-driving technology startup Pony.ai, and only applies to an area measuring about 23 square miles.

According to CNBC, a staff member needs to remain in the vehicle, though not necessarily behind the wheel.

Baidu, which has been operating a self-driving taxi service in Beijing for the past year, has been given permission to operate 10 so-called robotaxis without safety drivers, while Pony.ai has permission to operate four. Both companies plan to increase the number in the near future, though neither is allowed to charge for a ride in cars without a safety driver just yet.

Back in the U.S., Alphabet's Waymo has been offering its Waymo One service in parts of Phoenix, Arizona, for a couple of years. Waymo One also operates without a safety driver on board, and Waymo is currently looking at expanding the service to San Francisco, where its robotaxis are already operating, albeit for staff members only at present.

General Motors and Honda-backed Cruise also has robotaxis operating in San Francisco without a safety driver. Cruise has allowed members of the public to sign up for its service but hasn't said when the service will officially start.