Two new permits for testing driverless vehicles — granted on 8 March by California’s Department of Motor Vehicles (DMV) — have taken the total number of companies licensed to drive their prototype autonomous vehicles in the state to 27, according to the state’s automotive regulator (www.dmv.ca.gov/portal/dmv).

The latest entrants to the market are Uber, which saw its test vehicles banned from the roads of San Francisco in December, after it initially refused to apply for DMV approval, and Plus-AI, a start-up based in California and Beijing that was founded last year by David Liu and Hao Zheng.

Earlier this month, Renovo Motors — a Silicon Valley start-up developing “automated mobility on demand” — and Navya — a French creator of an autonomous electric shuttle — were added to the DMV’s approved list.

Meanwhile, Didi, the Chinese ride-hailing service, opened a new R&D centre in Mountain View to work on intelligent driving, cyber security and artificial intelligence.

According to the DMV, a total of 180 autonomous cars are currently being driven in California; 77 of these belong to Alphabet’s Waymo, which was the third company to register with the state’s testing programme.

After Waymo, the companies with the largest autonomous fleets are Cruise — the start-up acquired last year by General Motors for several hundred million dollars — with 27 cars and Tesla with 24.