SDCL § 32-25-17: Posting stop signs at intersections with increased maximum--Illumination of stop signs.

Local authorities shall place and maintain upon all through highways under their jurisdiction upon which the permissible speed is increased adequate signs giving notice of such special regulations. Local authorities shall also place and maintain upon each and every highway under their jurisdiction intersecting any said through highway, appropriate stop signs which shall be illuminated at night or so placed as to be illuminated by the headlights of an approaching vehicle.