Complain,
start carrying pen and paper, and write down liscence numbers. It doesn't do much; but a lot of police depts will send out a letter teling the driver to cool it. Also, if the jerk winds up standing in traffic court; the judge will see your complaint. It makes a difference. I feel fortunate that the drivers around here have been good. I can be aggressive in traffic; and people have been very nice about letting me through. Maine tends to be one notch more mellow than most places, and two or three notches behind Mass.