meh you may aswell report him, even if you have no luck. Atleast ask for a free test next time, worth a try. AnD In YOU NEXT TEST if you really paranoid bring a voice recorder :D , now When ever i get pulled over by cops i pull my phone out and press the voice recorder. Make sure they don't see you with the phone otherwise, they will try an book you for using a phone while driving. So if they try and cheecky shit (which some do), i will have somthing to back me up in court.
You never know, people may have reported him before, so another complaint might just get the ball rolling, for him to get the sack.