How do traffic signals detect motorcycles and bicycles?
A. Motorcycles and bicycles may have problems at some traffic signals when they encounter red lights because most traffic signals use induction loop vehicle detectors. The induction loop detectors sense the change in the magnetic field caused by vehicles that enter the signal detection zone. Motorcycles and bicycles do not have much ferrous metal and may have trouble activating a signal change at a traffic light. WSDOT keeps a record of and reviews locations at which motorists experience delays. Adjusting the existing detection equipment can sometimes improve detection. Typically, the best place to place your motorcycle (or bicycle) would be in the center of the lane within about one foot of the stop bar.
