S.D. Codified Laws § 32-31-4
The speed limit set out in §§ 32-25-1.1 to 32-25-17, inclusive, does not apply to any authorized emergency vehicle responding to an emergency call if the driver sounds an audible siren or air horn or both or displays flashing, oscillating, or rotating beams of red light or combinations of red, blue, or white light visible one hundred eighty degrees to the front of the vehicle. The lights must be capable of warning the public of the presence of an emergency vehicle under normal atmospheric conditions. The speed limit set out in §§ 32-25-1.1 to 32-25-17, inclusive, does not apply to authorized emergency vehicles operated by law enforcement officers who are measuring the speed of other vehicles by use of the emergency vehicle speedometer. An ambulance driver who is certified pursuant to chapter 36-4B may operate an ambulance in excess of the speed limit without audible signals while operating outside the city limits of a municipality.
SDCL 32-31-4