Anyone needing proof that China is ripe for carpooling need only look at how many licensed drivers the country has: about 250 million, the Ministry of Public Security said in November.

The huge rise in the number of cars on the country's roads over the past 20 years has almost inevitably led to traffic jams being the daily lot for many city dwellers, and car restrictions have been introduced in some big cities. Now local governments are looking to carpooling as a way not only of easing traffic congestion but reducing vehicle exhaust emissions, too.

In January 2014, the Beijing Municipal Commission of Transport published a paper on carpooling in the capital, with measures to protect the rights of car owners and passengers alike.

It says there are three kinds of carpoolers: those who commute to work and engage in carpooling on a long-term basis, those who go back to their hometowns during holidays; and those who travel together on the odd occasion. One of the most common arrangements is that owners and passengers share costs such as those for fuel and road tolls.

As with car-hailing apps, carpooling apps include insurance that covers users for the duration of a journey.