I have found that the Dutch use a lot of redundant detection for bicycles at signalized intersections.
Here's a particular example where they are pushing the stop bar forward at an intersection to improve sightlines. They detector is placed at the pole where one could push a button if they felt it necessary. They also give feedback for the cyclists, once the detector has identified a cyclists, it lights up the pedestrian push button. This is a nice treatment that we should use in the U.S.
They certainly put in a lot of poles. It is as if someone decided they were going to trade the costs of a mast arm pole for the pedastal mounted signals.