In the battle to build a self-driving car, the biggest, richest tech giants are falling behind. While Tesla and Uber are racing toward getting a fully autonomous vehicle to market—on Sunday Tesla announced a new update to its self-driving software, while Uber is expected to launch its first fleet of experimental self-driving cars in Pittsburgh any day now—Google’s program is reportedly languishing, despite having gotten a multi-year head start. Now Apple, which has been silently working on its own car project, has reportedly hit some major roadblocks of its own.

Not much is known about Apple’s ultra-secretive car endeavor, Project Titan. Apple has never publicly acknowledged the project, and C.E.O. Tim Cook has spoken in only the vaguest terms about the potential for an Apple vehicle. “There will be a massive change in the industry,” he said onstage in October at the WSJDLive conference. In July, the company appointed longtime Apple executive Bob Mansfield to head up the company’s car-making efforts, leading to reports that Project Titan and its team of reportedly “hundreds” of employees had been tentatively scheduled to launch in 2021.

Now, The New York Times reports, Apple is rethinking its self-driving-car strategy entirely. The Financial Times reports that “dozens” of Project Titan employees “have departed in recent weeks” as part of the shift in strategy. Under Mansfield’s leadership, the Times reports, Apple decided to stop building its own car, and focus instead on building the technology for a self-driving Apple car. Currently, the Times report says, Apple is testing self-driving vehicles on a closed track.

Apple’s efforts to make its own car are not entirely lost, however. Bloomberg reported in late July after the appointment of Mansfield that Apple would be putting its energy into developing self-driving-car technology, though in the future, the company could still partner with or buy its own carmaker rather than having to build a vehicle in-house. As iPhone sales slow, an Apple car could become a new flagship product for the tech giant as it seeks to compete not only with other tech companies but with traditional automakers for dominance in the self-driving-car market. Still, as Cook cryptically warned investors during Apple’s annual shareholder meeting in February, it won’t happen for a while. “Do you remember when you were a kid, and Christmas Eve, it was so exciting, you weren’t sure what was going to be downstairs?” He told shareholders. “Well, it’s going to be Christmas Eve for a while.”