This rumor gets a confidence level of 7/10. We are pretty confident that Google's Android in the Car interface will be functionally close to what we'll look at today, though the actual interface could change drastically. What's also important to note, though, is that manufacturers could still add their own interfaces to Android's car experience.
In a series of short video clips embedded below we interfaces for Music, Telephony, and Messaging. In the music app when there's artwork a translucent bar offers big, bold, pressable controls. A system navigation bar runs along the button and a Google Search icon is located at the top right. You can open the search interface by saying "Ok Google".
Users can enter a dialer that lets them select frequent contacts or dial a number; however, calls can also triggered by saying, "Ok Google, call [name]".
Sending a message can also be accomplished through voice commands by saying, "send a message", "send a message to [name]", or "send a message to [name] - I'm on my way." A blue color is used on screen to indicate when that Google is talking to the user to clarify a command. Notably, Google doesn't show the message onscreen. Instead, it reads the message back before requesting confirmation.
Voice commands can also trigger navigation and general search. The car icon at the far right of the system menu will presumably show information related to vehicle you are in. Additionally, AndroidPolice says there is some evidence that Google Now cards would be seen in a separate part of the interface.
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