How should you deal with people who dangerously tailgate you on the road? Befriend them! Here’s what you do: wave to them. It works amazingly well about 70% of the time. The driver either drops back and stays back, or they go around you, or occasionally they inspire a smile when they shyly drop back and change lanes as if to hide.
About 20% of the time they don’t respond, and about 10% of the time the person is a bit aggressive when going around you, but that matches well to the 1 in 10 psycho factor (1/10 people are crazy).
Try it next time someone is too close!