If they are the imbedded wire type where you can see the cuts in the asphalt, stop in the lane so that your wheels are directly on the right side cut (preferably both wheels). If the sensing level has been set right, it should be able to read your presence. On my commute, 95% of the sensors can read me, and the others I just have to work around. If you still don't have any luck with the sensors, call the city road engineer and see what the deal is.