N.D. Cent. Code § 39-21-50
All implements of husbandry, as defined in section 39-01-01, and machinery, including all road construction machinery, designed for operation at a speed of twenty-five miles [40.23 kilometers] an hour or less, must display either a triangular slow-moving vehicle emblem or a rotating or flashing amber light, as authorized for class B emergency vehicles, whenever traveling along the roadway on any county, state, federal highway, or city street in the state of North Dakota. The emblem or light must be mounted so as to be visible from a distance of not less than five hundred feet [152.4 meters] to the rear. The director shall adopt standards and specifications for the design and position of mounting the slow-moving vehicle emblem and light. The standards and specifications for slow-moving vehicle emblems referred to in this section must correlate with and, so far as possible, conform with those approved by the American society of agricultural engineers. No vehicle, other than those specified in this section, must display a slow-moving vehicle emblem, and its use on any type of stationary object is prohibited. Any person who fails or refuses to comply with the provisions of this section must be assessed a fee of twenty dollars for each offense.
N.D.C.C. § 39-21-50