In an interview with Bloomberg, Apple CEO Tim Cook admitted the company is working on an autonomous driving system for vehicles, calling it “the mother of all AI projects.” After being particularly secretive about Apple’s Project Titan vehicle research for years, Cook revealed that the company sees self-driving technology, electric vehicles and the expanding ride-hailing industry as “three vectors of change happening generally in the same time frame” within the automotive industry. Apple has invested $1 billion in Didi Chuxing—China’s biggest ride-hailing service—and decided last year to shift the focus of its endeavors away from making an electric car and toward perfecting autonomous driving technology. Apple has been granted permits to test its self-driving systems on California roads, but what form their product will eventually take is still an open question. “It’s probably one of the most difficult AI projects to work on. So autonomy is something that is incredibly exciting for us,” Cook said. “But we’ll see where it takes us — we’re not really saying from a product point of view what we’ll do. It’s a core technology that we view as very important.”