The city I live in uses pole mounted microwave vehicle detectors on practically every signaled intersection, as harsh winters would destroy the in ground variety. Even on a bike they work like a charm, just move left into the driving lane as you approach the intersection and the light changes.
However over the past year I've been encountering more and more intersections where I never get detected. A traffic engineer got back to me to say that they started using "true-presence" sensors that can eliminate false positives caused by the pole bouncing in the wind. It would seem cyclists falls within the threshold of a false positive and are duly ignored.
It creates a bit of a dilemma, if I know the intersection I'm approaching will never go green should I even bother waiting at the red at all. Some of these detectors are at intersections with dedicated left-turn lanes so there isn't even a pedestrian button to press. The problem will only get worse as old model detectors are swapped out.