I have a feeling that if the incline is steep enough (and I'm not sure how much enough would be) that the HAH will not AutoStop. The transmission already has a way to detect the grade of the road (GradeLogic) so it isn't too much of a stretch to think that the AutoStop programming will also make use of that information. OTOH, the electric motor produces a lot of low rpm torque (100 lb-ft @ 800 rpm) so if necessary it could overcome quite a steep grade and still start the ICE.