I can tell you, if a car would pass me by that close, and I'd be able to catch it up at a stop or a red light, I would break his mirror, and have no remorse. Some areas needs to be avoided as much as possible... Not sure if it's your case or not. My advice: Get yourself a camera & record your rides. Send it to the police if/when such incidents occur.
Where I live, we have a regulation of 1.5 meters (5ft) between cyclists and drivers, and almost nobody respects it. Law enforcement does not really check that unfortunately. They're too busy doing radar in speeding traps or checking for drivers using their cellphones. Guess it pays more!