License plates issued for motor vehicles must be attached to the outside rear of the vehicle, open to view. However, on truck tractors and road tractors the plates must be attached to the outside front of the vehicle provided that single unit commercial motor vehicles with a gross vehicle weight rating in excess of twenty-six thousand pounds may have the license plate on either the outside front or rear of the vehicle. Every license plate, at all times, must be fastened securely in a horizontal and upright position to the vehicle for which it was issued so as to prevent the plate from swinging. However, if a motorcycle is equipped with vertically mounted license plate brackets, its license plate must be mounted vertically with its top fastened along the right vertical edge. The bottom of the plate must be at a height of not less than twelve inches from the ground in a place and position clearly visible as provided in § 56-5-4530, and it must be maintained free from foreign materials and in a clearly legible condition. No other license plate, lighting equipment, except as permitted in § 56-5-4530, tag, sign, monogram, tinted cover, or inscription of metal or other material may be displayed above, or upon the plate other than that which is authorized and issued by the Department of Motor Vehicles for the purpose of validating the plate. It is not unlawful to place a decal or a frame on the license plate if it does not obscure any letters or numbers. A motor vehicle owner may attach a trailer hitch to a motor vehicle provided the hitch does not obscure more than two inches of the license plate issued to the motor vehicle. It is unlawful to operate or drive a motor vehicle with the license plate missing and a person who is convicted for violating this section must be punished as provided by § 56-3-2520.