Summarize this article:

Attempt to boost the electromagnetic detection of your small vehicle in an inductive loop system by attaching a small, powerful magnet to the underside of your motorcycle or bike.  Note that many find that this method is not very effective, though others have shown that it may make a difference when the magnet is moved over the loop detector at a slow speed rather than standing still.  Take care in handling powerful magnets like neodymium magnets. They can interfere with pacemakers, electronic devices, and navigation systems. They can be harmful if they collide and break, corrode, or pinch fingers and other body parts. Try lowering your motorcycle's kickstand directly onto one of the loops that you see indicated by grooves in the road's surface.  It is possible that this small extra quantity of conductive metal placed directly on a loop's edge can help trigger an inductive loop detector system.  This will only make a difference on an inductive loop detector, though making more of a movement on your motorcycle (to put down the kickstand or otherwise) may still help in triggering a camera detector as well. Never attempt to activate the Traffic Signal Preemption systems in place for emergency service vehicles to travel more quickly and safely through intersections, achieved only through special transmitters and sensors.  It's a myth that flashing the high beams on your vehicle can activate the sensors that detect special infrared transmitters in emergency vehicles and some public transportation vehicles.  There are some transmitters sold that effectively transmit the right signal to activate these sensors, but they are illegal to own unless authorized for an emergency services or public transportation vehicle.

Summary:
Try a neodymium magnet. Put your motorcycle's kickstand down. Avoid illegal strobe light transmitters.