I was driving down Tillary St. in Brooklyn yesterday and reached a major intersection (I believe to get onto the Brooklyn Bridge.) There were three of four traffic cops in the road, waving on and stopping traffic. In a way that, as far as I could tell, exactly matched what the traffic lights said to do.
What could the point of this be? All I could see was that it created confusion by dividing drivers' attention between two sources of control over the intersection. Maybe its some punishment the NYPD assigns to cops on the verge of being fired.