SDCL § 32-25-28: Exceeding posted speed limit permitted under certain conditions.

The speed limit is increased by ten miles per hour over the posted speed limit, if a person is driving a vehicle that is:

(1) On a two-lane highway that has one lane for each direction of travel;

(2) On a highway with a posted speed limit that is equal to or exceeds sixty-five miles per hour;

(3) Overtaking and passing another vehicle proceeding in the same direction of travel; and

(4) Passing a vehicle that is moving slower than the posted speed limit.