It looks like Google Assistant in the new Android Q software will be mostly replacing Android Auto’s Driving Mode. That’s being moved to Google Assistant, and also means that the Android Auto app on your phone is no longer accessible.
You won’t be able to access Android Auto via the app drawer and use it like any other app. It’s still installed and regularly updated on your phone, but you won’t be able to open it up.
Instead, Android Auto will likely act as a gateway or “passthrough” so that your phone can talk to your car when connected. That said, Android Auto is going to be exclusively for cars. This actually puts Android Auto in a similar position as Apple’s CarPlay, where Driving Mode is handled by Siri, and actual CarPlay functionality is exclusive to the vehicle.
For now, users on Reddit are starting to see all of this in the Android Q Beta. That means that Google Assistant’s Driving Mode isn’t quiet ready to takeover yet, but will likely be happening when Android Q is ready to launch to consumers this fall.