S.D. Codified Laws § 32-28-8
Meaning of flashing yellow signal--Violation as misdemeanor
If a yellow lens is illuminated with rapid intermittent flashes, drivers of vehicles may proceed through the intersection or past such signal only with caution. A violation of this section is a Class 2 misdemeanor.
Source: SL 1963, ch 274, § 3 (2) (a); SL 1989, ch 255, § 191.