German automaker BMW and Chinese internet giant Baidu will end their joint research on self-driving cars, executives for the two firms said on Friday, with Baidu now searching for new global research partners.

Wang Jing, the head of autonomous car development at Baidu bidu , told Reuters the company was now using cars from Ford’s Lincoln in its U.S. testing, declining to elaborate.

“I’m open for any partners, actually I’m talking to many,” Wang said, speaking on the sidelines of China’s third World Internet Conference in the eastern Chinese city of Wuzhen.

Tech and automotive leaders contend that cars of the future will be capable of completely driving themselves, revolutionizing the transportation industry, with virtually all carmakers as well as companies such as Alphabet’s Google and parts supplier Delphi investing heavily in developing the technology.

The two companies decided to end the cooperation, which involved testing in the United States and China, because they held different opinions on how to proceed with research, BMW’s China CEO Olaf Kastner told Reuters at the Guangzhou auto show, which began on Friday.

“We now have found that the development pace and the ideas of the two companies are a little different,” Kastner said, without specifying the exact point of disagreement.

 

At the conference in Wuzhen, Baidu offered test drives of various autonomous driving prototypes developed separately with Chinese automakers Chery, BYD, and BAIC Motor.

The test cars drove a closed road, automatically avoiding a bicycle and overtaking cars moving at various speeds.

BMW’s Kastner said the two made decisions to part ways after jointly developing the automatic overtaking capability, seeing it as a key milestone for the technology.

The German automaker plans to expand its research and development team for autonomous drive in China, Kastner said.

The two companies will continue to be partners on high-definition maps, which are a vital to the navigation of autonomous cars, he added.

Baidu aims to commercialize autonomous cars on a small scale by 2018, with wider deployment by 2021. BMW bmwyy has similarly targeted highly or fully autonomous cars by 2021.

Last month, China issued its roadmap for the development of self-driving cars that can drive in most situations between 2021 and 2025, with nearly every car having some self-driving capability by 2030.

That roadmap did not back a single technology for self-driving cars to communicate with each other, leaving the possibility it could back a different standard from Europe or the United States.