Wash. Rev. Code § 46.61.184
Notwithstanding any provision of law to the contrary, the operator of a bicycle, moped, or street legal motorcycle approaching an intersection, including a left turn intersection, that is controlled by a triggered traffic control signal using a vehicle detection device that is inoperative due to the size or composition of the bicycle, moped, or street legal motorcycle shall come to a full and complete stop at the intersection. If the traffic control signal, including the left turn signal, as appropriate, fails to operate after one cycle of the traffic signal, the operator may, after exercising due care, proceed directly through the intersection or proceed to turn left, as appropriate. It is not a defense to a violation of RCW 46.61.050 that the operator of a bicycle, moped, or motorcycle proceeded under the belief that a traffic control signal used a vehicle detection device or was inoperative due to the size or composition of the bicycle, moped, or motorcycle when the signal did not use a vehicle detection device or that any such device was not in fact inoperative due to the size or composition of the bicycle, moped, or motorcycle. For purposes of this section, "bicycle" includes a bicycle, as defined in RCW 46.04.071, and an electric-assisted bicycle, as defined in RCW 46.04.169.
RCW 46.61.184