No routes may be marked within or through the state until an exact description of the routes selected for marking have been filed with the Department of Transportation and the route and marking have been approved by the department. Any routes previously marked between any two adjacent points in South Dakota shall be made to conform to the trunk system between the same points.

Source: SL 1919, ch 333, § 52; SDC 1939, § 28.0904; SL 1984, ch 207, § 69.