just avoid it as much as possible. I stopped using my sat/nav 3 years ago.
had I "listened" to the nav on my 2003 Maser Coupe CC while driving to the FM dealership one day. I admit I was "in the area" of an offramp but it was still 1/4 mile away when the Nav told me to "Exit freeway now". I really don't use the thing; it is light years behind my wife's Jaguar Nav system!!