City complaint, who to call?

Today, my wife was riding her bike on a street designated by our city as a "bike blvd." Basically, it's a street with roundabouts instead of stop signs, and additional signs alerting cars to the high frequency of bicycles used in the lanes. It is a residential street in a very quiet area. As she was riding, a trash truck pulls from an alley without stopping to check for vehicles or pedestrians. My wife is forced to lock up the breaks, yells out a "watch out" type of phrase, and has to stop in the street to avoid hitting the truck. The truck never stops. As a means of response, the driver flips her off as he finishes his turn and drives down the street. We're not the type to complain about trivial stuff, but this one got to me. I can't believe a city employee would flip off a citizen while in a city vehicle.

My question: Who do I contact? Do I call the refuse department and ask for a supervisor? Do I contact my city council representative? City Manager? Local paper? All of the above? I don't want to overreact, I recognize that people make mistakes while driving, but the flipping off is totally unacceptable. Let me know what you think.