We have a poster on our safety board that addresses this very issues.
It says that while we should stay out of residential driveways if we must back in to one we should strive to be a quarterback; that is, we should only back far enough to get off of the street. If that is not possible, we should then strive to be a halfback, backing halfway in to the driveway. We should do all that we can to not be a fullback, backing all the way in to the driveway. I would think the only time this would be an option is if we have an Over 70 w/o a handcart.