An itinerary log of carpooling.

She even bought insurance from one driver, she says.

"Thanks to such apps, I don't have to push myself to learn how to drive or buy a car."

Shao Fang says carpooling helps her build trust with strangers, and she has become more willing to step in to help anyone in need.

"I've carpooled in expensive cars such as Mercedes, BMWs and Land Rovers," says Shao, who adds that she has used carpooling apps 80 times in the past six months. "The car owners are very nice.

"There are always these little heart-touching surprises. These days people are busy and often have no time for others. It's good to have these apps that change our lives just a bit."

Since she began carpooling she has undergone many changes, she says. Many of these may be imperceptible, but she feels she now has a brighter personality and is more apt to talk with others.

Car owners and passengers can comment and leave their first impression of each other on profiles visible to users. As with social media, they can include details such as age, occupations and hobbies.

"Most of our car owners are middle-class and aged from 25 to 45," says Li Jinlong, cofounder and marketing vice-president of Dida Pinche. "We want to make it more pleasant to go out and bring strangers closer. We offer bonuses to car owners based on these comments, to encourage people to communicate more on cars."

Duan says: "I feel that what they offer is a real person, rather than a service. It's nice reading some of the comments people leave. One comment I saw consisted of an ancient poem. I put a lot of effort into writing my comments because I realize those who read them will draw the same kind of satisfaction as I do from such feedback."

Zhu Di, an associate professor at the Institute of Sociology, Chinese Academy of Social Sciences, says car pooling apps are presenting a new way for people in big cities to make friends and expand their social circles.

Chinese are more reticent than Westerners to talk with strangers, she says, and sitting in a car provides an ideal venue for chatting, she says.

"The ways we interact socially are changing and they can be broadened. Social intercourse traditionally refers to acquaintances sitting together and chatting. But in a busy world doing that takes a lot of time.

"In big cities, young peoples' social circles tend to be limited, and for Chinese it takes time to become acquainted with others and form friendships. But every instance of social interaction does not necessarily have to lead to a friendship being formed."

xulin@chinadaily.com.cn