An easier ride, but for some only (4)

"That's why we need the tip function," he said, although he insisted it is not compulsory for all users.

Shanghai's traffic management administration has welcomed the introduction of the taxi apps, but has raised questions about the tipping system.

"We can't easily say no to new things that benefit passengers, improve the quality of service and put resources to better use, but there has to be some standard form of management," said Sun Jianping, head of the Shanghai Municipal Transport and Port Authority.

"If every cabbie goes for the big tips, who is left for those who can't afford to tip?"

Meanwhile, the Shanghai transport authority is considering a proposal by cab companies to introduce a fee for phone reservations.

Dazhong Taxi Corp already charges a 4-yuan fee, while the other three large companies are planning to introduce the fee after Spring Festival.