We have a pretty good notion that. And thanks to a recently published Apple patent, we have a better picture of what that might entail.
According to the patent (as spotted by Patently Apple) Apple imagines a self-driving car that calculates its route in advance and then makes it clear to the human "driver" each move it'll make ahead of time. We're not just talking about GPS: Apple imagines a "Countdown Indicator" that counts down the seconds until the autonomous car will make a maneuver.
While there's no guarantee that the patented idea will ever make its way into a real Apple product (it was originally filed Sept. 2015), it does give us an idea of how Apple thinks future self-driving cars might work.
One potential issue with self-driving cars is getting the human passengers to actually trust them, but if passengers know the car will do ahead of time, that might address the fear. By counting down the seconds before a maneuver, riders will generally know what'll happen and when.
You can read the Apple patent in its entirety here.
Apple didn't immediately respond to a request for comment.