I see a lot of naysayers here. Remember, the iPhone started out in ONE country with ONE service provider and expanded to be a world phone with lots of providers today.
The Apple Car could start out in one city with the only service being taxiing people from one place to another within the city. If they started in New York, they could map out literally every square inch of the roadways and offer shuttling services for people wanting to go from point A to point B within the limits of the Apple Car's driving map. For this kind of service, there would be no need for a driver, steering wheel, or brake pedal. Apple could then expand to other cities.
I believe in the future, most individuals are not going to own cars. Cars will become autonomous shuttle vehicles. No more need for huge parking lots, driveways, or garages. You'll just tell your phone, "I need a ride to [X location]," and a driverless shuttle car will arrive within two minutes to take you. When you are done, you will say, "I need a ride home," and another car will arrive quickly to take you home. I think Apple sees this future and is not creating a car to be owned by individuals.