CHONGQING, April 12 -- Two driverless cars produced by Chang'an Automobile in China started a 2,000-km test drive from Chongqing to Beijing on Tuesday.

Li Yusheng, engineer-in-chief of Chang'an Automobile Engineering &Research Institute, said the drive will help test their functions in diverse conditions.

"The vehicles have performed well in uncomplicated road conditions, such as urban driveways and highways, but they still need the help of a driver to navigate them in places like gas stations and toll booths," said Li.

"We want to improve the vehicles' sensors and processing technology, and then to prepare models for mass production," said Tan Benhong, deputy director of the institute.

Chang'an is aiming to put driverless cars into commercial use in 2018.

Worldwide, at least 18 companies are developing autonomous cars, including BMW, Audi and Toyota. China's contenders include auto makers BAIC group, GAC Group, SAIC Motor, Chang'an and BYD.