Re:He seems a dangerous driver (serious) (Score 2, Informative)

I'm not sure about other states but in California it is legal to flash your lights at a slow driver in the left lane. It's just not legal to flash your high beams because of that blinding, swerving, and crashing thing. It will also blind the car you are folowing, not just oncoming trafic, because of the rear view mirror. That's why when you are pulled over at night there is usually a bright white light on the crusers light bar shining into your car, and it helps them see you better.