S.D. Codified Laws § 32-18-9 (2026)
Tests for deceleration and stopping distance under § 32-18-8 shall be made on a substantially level (not to exceed plus or minus one percent grade), dry, smooth, hard surface that is free from loose material.
Source: SDC 1939, § 44.0346; SL 1967, ch 197 , § 2.