BMW is no longer working with China’s Baidu on autonomous vehicle research and development. They began working together in 2014, leading to Baidu’s use of modified BMW 3 sedans in its autonomous vehicle tests in China. Baidu is currently using Ford vehicles instead.

Olaf Kastner, CEO of BMW China, told Reuters that the companies had to end their partnership due to a disagreement over how their development work should move forward. This left Baidu needing to look for a new partner.

During their partnership, Kastner says they co-developed technology that allows autonomous vehicles to pass other cars.