WTF is Apple Car Play ?
Apple Car Play is pretty much Apples version of Mirrorlink, theres a bit of Political history involved, Mirrorlink was originally developed by Nokia when they developed 'Car Mode' which was originally designed for thier own Symbian, Meego and early Windows OS Mobiles, the idea being that a simple Car Mode Touch Screen / AVI could be mirrored to a Cars Screen via USB or Bluetooth APi.
Nokia, as they did a lot in them days, then released their development as an Open Source Platform, so that like minded Equipment manufactures, Mobile, Car Audio, Vehicles and OS and 3rd Party App Developers could bring it all forward in harmony as a future standard.
Apple didn't wont to play ball or participate, probably through arrogance, as Apple, at the time, saw Nokia jumping in to bed with Microsoft as a big threat to their iPhone product, how wrong they where, well from MS point of view anyway.
Mirrorlink is well established now, with Android, Windows phone, Blackberry devices and plenty of Apps out there making use of it. Apple's Car Play is its own propriety, meaning Vehicle manufactures will need to choose which one to commit to, as there not i any shape or form compatible, meaning one of two things will happen, Apples Car Play will end up a dead duck, or knowing Apple, they will make a Marketing success of it and Consumers will be faced with yet another decision when buying a new Car or replacing the the Cars OEM Audio System.