RCW 46.37.467: Alternative fuel source—Placard required.

(1) Every automobile, truck, motorcycle, motor home, or off-road vehicle that is fueled by an alternative fuel source must bear a reflective placard issued by the national fire protection association indicating that the vehicle is so fueled. Violation of this subsection is a traffic infraction.

(2) As used in this section "alternative fuel source" includes propane, compressed natural gas, liquefied natural gas, liquid petroleum gas, or any chemically similar gas but does not include gasoline or diesel fuel.

(3) If a placard for a specific alternative fuel source has not been issued by the national fire protection association, a placard issued by the chief of the Washington state patrol, through the director of fire protection, is required. The chief of the Washington state patrol, through the director of fire protection, must develop rules for the design, size, and placement of the placard which remains effective until a specific placard is issued by the national fire protection association.