S.D. Codified Laws § 32-17-29
Every operator of a motor truck, tractor, truck tractor, farm tractor, road tractor, or road patrol, or any combination thereof, including trailers and semitrailers, and all vehicles exceeding a width at any point of eighty inches, shall, immediately upon bringing his vehicle to a stop upon the traveled portions of any public highway, place three flares, red electric lights, red reflectors, or emergency reflective triangles on the roadway. If traffic on the roadway moves in two directions, one of these devices shall be placed at least one hundred feet in the front, one at least one hundred feet to the rear, and one alongside the stopped vehicle. Upon a one-way roadway or divided highway, one of these devices shall be placed at least one hundred feet to the rear, one at least two hundred feet to the rear, and one alongside the stopped vehicle. The flares, red electric lights, red reflectors, or emergency reflective triangles shall be of such type of construction as will furnish continuous light for a period from sunset to sunrise at all times of the year. It is the responsibility of the driver or the person in charge of the vehicle to remove the vehicle in the most expeditious manner. Any vehicle found parked in violation of this section may be immediately removed to a place of safekeeping as directed by a police officer. Any vehicle removed pursuant to this section shall be disposed of as directed by §§ 32-30-15 and 32-30-18. A violation of this section is a Class 2 misdemeanor. A subsequent violation is subject to § 32-17-30.
This section does not apply if the stopping is momentary, in obedience to an intersection stoplight, or conforming to the movement of a line of traffic or within the corporate limits of a municipality.
SDCL 32-17-29