S.D. Codified Laws § 32-26-4
Mountain highways--Curves--Keeping to right--Violation as misdemeanor
The driver of a motor vehicle traversing defiles, canyons, or mountain highways shall hold such motor vehicle under control and as near the right - hand side of the highway as reasonably possible. A violation of this section is a Class 2 misdemeanor.
Source: SDC 1939, § 44.0327; SL 1989, ch 255, § 144; SL 1989, ch 256, § 23.