Either the rear lamp or a separate lamp shall be so constructed and placed as to illuminate with a white light the rear registration plate and render it clearly legible from a distance of fifty feet (50') to the rear. When the rear registration plate is illuminated by an electric lamp other than the required rear lamp, the two (2) lamps shall be turned on or off only by the same control switch at all times when headlamps are lighted. (2008 Code § 17-388)