No motor vehicle required to be registered in this state and which is operated on the highways of this state may be equipped with one - way glass, adhesive film, or other glaze in the rear windows behind the operators seat that reduces light transmission below twenty percent, with an enforcement tolerance of nine percent. A violation of this section is a Class 2 misdemeanor. Source: SL 1988, ch 257 , § 2; SL 1989, ch 255 , § 232; SL 1994, ch 257 , § 2.