SDCL § 31-8-11: Elimination of grade crossings.

The state or any of its subdivisions may provide for the elimination of intersections at grade of controlled-access facilities with existing state and county roads, and city or town streets, by grade separation or service road, or by closing off the roads and streets at the right of way boundary line of such controlled-access facility. After the establishment of any controlled-access facility, no highway or street which is not a part of the facility may intersect the facility at grade.