(1) Every farm tractor, self-propelled unit of farm equipment, implement of husbandry designed for operation at speeds not in excess of twenty-five miles per hour and every combination of farm tractor and towed farm equipment or towed implement of husbandry normally operated at speeds not in excess of twenty-five miles per hour must at all times be equipped with a slow-moving vehicle emblem.

(2) Other classes of vehicles not covered by RCW 46.37.160 such as road construction vehicles and road maintenance vehicles which normally operate at a speed of twenty-five miles per hour or less may be equipped with slow-moving vehicle emblems meeting the requirements of this section.

(3) In order to comply with the provisions of RCW 46.37.160(6), slow-moving vehicle emblems:

(a) Must be constructed in conformance with SAE Standard J943.

(b) Must be mounted point up in plane perpendicular to the direction of travel of the vehicle so that the reflectorized side of the emblem is facing to the rear.

(c) Must be mounted, as nearly as is practicable, centrally at the rear of the vehicle in an unobscured location.

(d) Must be mounted not less than two feet nor more than six feet above the ground on which the vehicle stands measured from the lower edge of the emblem.

(e) May be permanently attached to the vehicle. Where portable brackets are used, they must be so constructed that they will hold the emblem securely and in a position meeting the requirements of all other mounting instructions under this section.

(f) Must be placed on the towed unit if the towed unit is sufficiently large to obscure the slow-moving vehicle emblem on the farm tractor, the towed unit must be equipped with a slow-moving vehicle emblem. In such cases, the towing vehicle need not display the emblem. Where the slow-moving vehicle emblem on the farm tractor unit is not obscured by the towed unit, then either or both may be equipped with the required emblem.

(g) Must not replace any of the required lamps or other devices required in chapter 46.37 RCW.

(h) Must not be used as a clearance marker for wide equipment.