S.D. Codified Laws § 32-15-10 (2026)
Every motor vehicle when operated upon a highway shall be equipped with a horn in good working order capable of emitting sound audible under normal conditions from a distance of at least two hundred feet. A violation of this section is a petty offense.
Source: SDC 1939, § 44.0347; SL 1989, ch 255 , § 37.