They made a statement about this somewhere. The antenna is too small to provide sufficient data for 'turn by turn' GPS, so it would make sense that the software isn't designed for driving.
The GPS is intended for Geo-tagging, and using Google Maps for find local services. Something my 1st gen iPhone does real well without draining the battery with GPS.
That is not true at all. I read the same thing, but it is simply not true. The GPS functions in the car, so there is no reason that it can't do turn by turn voice directions. If the phone can get the signal in the car, which it can and does, then all it would take is for the SOFTWARE (not hardware or antenna) to announce when a turn is coming up and which direction you will be turning.
The whole thing about the antenna being too small for turn by turn directions is completely asinine.