[BelleoftheBall]

I was always taught that the middle lane is the driving lane and you should only be in the right lane to take an exit or build up speed from an on ramp and the left lane is the passing lane. That being said years of driving, "unofficially" the common curtesy is if you are slower you stay to the right. But I do have to agree when I am unsure I am also in the middle lane because exits tend to "pop up" in the right lane.