SDCL § 32-15-2.5: One-way glass, adhesive film, or other glaze in rear window prohibited--Violation as misdemeanor.

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.