These registrations could be for a number of applications. Of course, Apple is said to be working on its own car, with the company having already met with California DMV officials over regulations for self-driving cars. Apple's Car is reportedly set for a 2019 or 2020 debut.
Of course, it's also possible that these domains registrations are centered around CarPlay. The in-car dash system, which allows people to connect their iPhones to their cars, is now standard in a rising number of vehicles, as well as third-party head units. CarPlay allows iPhone owners to use features like messaging, music, and navigation on a car-friendly display built into their car's console.