As demonstrated on stage, the system relies on an Android phone connected to the car. The phone serves as a processor and data conduit to the cloud, while the car's dashboard and LCD serve as the interface for features such as navigation and messaging.
Google Voice is a big part of Android Auto, so most users will spend plenty of time looking at this screen while commands are being processed. Or hopefully, ignoring this screen and keeping their attention on the road.
The Open Automotive Alliance, for which Android Auto was developed, includes a variety of automakers and tech companies. The first cars with Android Auto should become available by the end of the year.