S.D. Codified Laws § 32-17-7
Whenever a motor vehicle, except a moped equipped with a single beam headlamp as provided in § 32-17-24.1, is being operated upon a highway, or a portion thereof, which is sufficiently lighted to reveal a person on the highway at a distance of two hundred feet ahead of the vehicle, the driver shall tilt the beam downward. Whenever a motor vehicle meets another vehicle or overtakes another vehicle proceeding in the same direction on any highway, the driver shall tilt the beams of the headlamps downward, provided that at all times, as required in § 32-17-4, at least two lights shall be displayed on the front of and on opposite sides of every motor vehicle other than a motorcycle. A violation of this section is a Class 2 misdemeanor.
SDCL 32-17-7