Li Xiaodong rode on his scooter to downtown dining area of Shijiazhuang, Hebei province, and began his side job as designated driver. He drives those who had a few drinks and can't drive themselves.

The business of designated driving is booming in the holiday season, thanks to the launch of apps that helps match drivers and customers based on their proximity.

"There are more than 1,000 drivers engaged in this business, 90 percent of whom work part-time," said Zhang Dongpeng, a marketing manager of E-Daijia, a designated driving app.

The service fee is 39 yuan ($6.4) within 10 kilometers from 7 am to 10 pm, 59 yuan from 10 pm to 7 am. The driver can charge 20 yuan for every additional 10 kilometers, according to an industry professional.

Designated driver Li Xiaodong asks a customer to fill in a form in Shijiangzhuang city, Hebei province, Dec 17, 2014. [Photo/IC]