There are many useless traffic signals. (Some are also useful).
The most useless traffic signal I see everyday (multiple times) is at the intersection of Beacon St. and Harvard Avenue. Not only is there little traffic for the traffic light, so a stop sign (or better a yield sign, roundabout, or shared space) would do, the pedestrian signal has Beg buttons. I just saw someone who looked a lot like Eric Kaler (who is obviously not an idiot) waiting and needlessly obeying the law while pushing the pedestrian signal actuator multiple times to call for a walk signal, which eventually came. If no one pushes the actuator, you actually don't get a walk signal, so it is working, just pointless.
Why do we have these signals, on a university campus of all places, making pedestrians (who probably are equal in number to cars at this intersection) stand there like idiots while cars can drive through, and even make a "right turn on red"?