Inductive sensors will not react to magnetic fields - such as those rabbit-foot "good luck" magnets sold in the back of motorcycle magazines. I worked for a city engineering department for 35 years and I once asked our signal maintenance crews how they checked for proper operation of their traffic signal sensors. (The State requires their contractors to use a test moped to adjust the sensitivity of new controllers.) Once installed these induction loops and their sensitivity to vehicles get out of whack all the time. What our crews did was to throw a metal shovel on top of the loops and if that triggered the signals then all was well. Unfortunately many motorcycles with aluminum wheels make less of an impression on the loops than a steel shovel. (My Triumph, with its heavy steel rims, will set off most every signal.)
Sometimes deploying the side stand over a loop can help - otherwise you may have to either run the signal and hope for the best, or make a right turn and then a U-turn. Getting off the bike and pushing the ped signal button usually works, but that has its own hazards and could be illegal.
However, if you find a signal that will not detect your motorcycle, your best approach will be to contact the local DPW and they might readjust the signal detection loops - depending upon how they feel about motorcycle owners in general.
The latest detectors that are being deployed, for both new signal installations and to replace old induction loops are video detectors. These use a video camera to look for vehicles that are waiting at the intersection. They tend to work very well and can even detect bicycle riders. Plus, they are cheaper to maintain, as they don't have loops that can fail, or be cut or damaged when repaving the intersection or installing new underground utilities. Every signal detection device has its pros and cons, but the latest video detection systems seem to have a lot of pros.
