For what it's worth I have driven the 100+ miles route between Stevens Point and Madison Wisconsin numerous times on AP1 over the last few months. There are two or three spots where the car would inexplicably drift over the right hand lane marker onto the shoulder. And there is a construction zone with confusingly painted lane markers maybe 15-30 miles north of Madison which would also trip up AP1. I'm now driving an AP2 Model X on 8.1. So far it has aced these spots.