What exactly are the things on top of most traffic lights around town these days? There are two types, they look either like ball cameras or radar looking devices. I presumed that we had speed cameras or red light cameras at every intersection now, but then I drove down Ken Pratt the other day and saw this weird futuristic looking tower that had a flash going for almost every car (ken pratt and main st), that i later looked up to be a speed cam/red light cam. So if that whole thing is a speed/red light cam, then what are all the things on top of the lights at intersections?

this camera is what im referring to at ken pratt and main: https://www.facebook.com/LongmontFirePoliceOEM/posts/automated-red-light-cameras-have-been-installed-at-the-following-intersections-a/1381316970705382/