[mpasternacki]

This has been implemented for some traffic lights in Warsaw, and has one more bad side effect (possibly because of bad implementation): if you a bike in the late evening on the smaller street, that's configured "red unless there's a car that will be crossing" to maximize throughput of the bigger street, you have to wait for a car or use a pedestrian crossing, because the loops won't detect a bike.

[mnw21cam]

Lots (most?) of the traffic light controlled junctions in the UK have induction loops to detect cars. I have personally complained to the authorities about their lack of ability to detect bicycles.