In NC, the rule for motorcyclists is that they must wait three minutes before concluding that the signal is not working (since that's almost always longer than the maximum cycle time) after which the signal may be treated as a stop sign. There is no statute here for bicyclists, but the same logic applies.

At a very busy intersection or one with poor sight lines, it may be impossible to safely proceed without signal protection. This is why it is important for engineers to design and tune signals to detect all vehicle types.

Traffic signals with buried demand actuators use metal detection, not weight, to detect vehicles. These loop detectors use elecromagnetic induction principles based on Lenz's law to detect conductive objects above them. They can easily be adjusted to detect metal bicycle rims. The closest signal to my house will detect an aluminum bicycle rim, with no other metal, placed over the center wire cut, where the alternating electromagnetic field is strongest. I used a nylon bolt to attach an aluminum rim to a piece of wood in order to test this, and to provide my city's public works department with a compact calibration device for bicycle detection.

http://www.humantransport.org/bicycl...nals/green.htm