Catch 22,, ( depending on local laws ) a screen is allowed for navigation purposes, but quite a few screens can be configured for both. Its up to you to use it properly. The best set up I've seen up to date is a screen & console that replaced the front map lights... but forget about using your rearview mirror.

I've got my laptop between my seats for long trips, connected to my GPS.. which works fine for me, but I do have the slow speed, shifter + screen conflict.. but that is what my wife's lap is for.