I think users are spending to much time looking at the screen. When I am driving I only (sometimes) look at the screen when it tells me in 400 meters turn left or right. The same with driving on the highway. It tells you to take the 15 you take it. Again why do I need to look at the screen when you see exit 15 in front of you....? Then it tells you at the end of the exit turn left on to XYZ.
The arrow show where you are at all times in your drive it is not covered over by the blue info screen that sits on the top of the phone screen. At no time does it mask where you are at any one time. Is it that important to see the whole map when driving? The most important thing is just get me from point A to point B. You get speed cam warnings and info in the side panel if you need to look at it. In most cases users know where they are driving to even if it is the first time going to some place you listen to the instructions on how to get there.
Keeping you eyes on the road is the most important thing you can do. Try telling the officer that you were looking to long on the screen and did not see the car in front of you when you hit it.

The GPS TomTom Mod does a very good job of telling to how to get someplace with all the voice info you need. If it tells you something that is not correct you use your common sense not to do that even if the voice instructions are tell you to do that. Looking on the map will not help you when it comes to a mistake in the voice instructions.