S.D. Codified Laws § 32-28-6
Flashing red or yellow signal--Violation as misdemeanor
If an illuminated flashing red or yellow signal is used in a traffic sign or signal, vehicular traffic shall obey such signal as provided by §§ 32-28-7 and 32-28-8 . A violation of this section is a Class 2 misdemeanor.
Source: SL 1963, ch 274, § 3; SL 1989, ch 255, § 189.