The best option would be for ongoing training for driving. Agreed 100% there!

The problem (and probably why you’re getting downvoted) is that physically using your 2-ton vehicle travelling at freeway speeds to coerce someone into doing something is not really communicating. It’s not a method prescribed by any kind of authority or training, and is actively discouraged by most! Sure it may get the result YOU want in the moment, but communication requires understanding.

Personally, if someone were to overtake me and then slow down intentionally, I’d take that as them being an inattentive driver at best, and a passive-aggressive jerk at worst.