(A) (1) The municipality may modify the method of turning at intersections provided by §§ 71.070 and 71.071(A) by clearly indicating by buttons, markers, or other direction signs installed within an intersection the course to be followed by vehicles turning thereat. No such signs or buttons shall be placed upon any state highway without the approval of the Department of Transportation.
(2) If the municipality modifies the method of turning, it shall be a violation not to turn in the indicated manner.
(B) When an intersection is so constructed and laid out that different and clearly defined courses of travel are provided for vehicles turning to the left or right, as the case may be, it shall be lawful for any driver in making any such turn to follow the course thereby indicated.
(SDCL § 32-26-20) Penalty, see § 70.99