I think the app layout when on the car head unit display should be split. (It has already been suggested in a post about low resolutions)
- A split display could make it a lot clearer, since with the current floating turn directions/menu, the map is partially hidden when your route takes you left (since the car icon doesn't have enough horizontal offset)
- A delimited box for the map could enhance its visibility.
- The instructions pane could take the whole height of the display and thus use larger fonts/icons or provide better overall readability