China has launched four small fleet of self-driving public buses on trail on the roads of its tech district of Shenzhen, Guangdong.

These four buses are nearly full-sized and able to carry up to 19 passengers, reports Mashable.

They can also run over three stops on a public road about 1.2 km (0.75 mi) long.

The Chinese buses will go up to about 40 km/h (24.8 mph), and are equipped with the typical sensing tech you'd find on other autonomous vehicles, such as Lidar, cameras and a GPS.

The fare is 1 yuan (15 cents USD), although it's free for the trial period.

The public trial of the Alphaba project comes after rounds of private tests, which have already seen the buses cover about 8,000 km prior to this, China Daily reports.

The Shenzhen Bus Group, which runs Alphaba, has pledged to start similar autonomous trials in 10 more Chinese cities after this one wraps.

It intends to add more technologies to the buses too, including a way to analyse peak passenger traffic periods, so that buses can automatically adjust their dispatch schedules to match.

The city of Shenzhen opened the 1.2 km self-driving test route in September, together with another longer one stretching 3 km (1.86 mi), to cover 10 stops.