Originally Posted by JeffB502
If the sensors aren't detecting your bike (and it has a metal frame) then the sensor is malfunctioning or you aren't stopping on it. Usually there are little grooves in the pavement where the loop is embedded. If you're stopped on that and the light doesn't change after a reasonable time you should contact your city streets maintenance department and report the sensor is not detecting your vehicle.
One of my bikes is all carbon fiber. There's no way it will ever trip those sensors.
Hell, my steel Lemond doesn't trip them either.