R.I. Gen. Laws § 31-24-9: Illumination of rear registration plate — Wiring of rear lights in connection with head lamps.

Either a tail lamp or a separate lamp shall be constructed and placed as to illuminate with a white light the rear registration plate and render it clearly legible from a distance of sixty feet (60′) to the rear. Any tail lamp or tail lamps, together with any separate lamp for illuminating the rear registration plate, shall be so wired as to be lighted whenever the head lamps or auxiliary driving lamps are lighted. Violations of this section are subject to fines enumerated in § 31-41.1-4.