S.D. Codified Laws § 32-18-2
Wheels on which brakes must act--Particular vehicles
Every vehicle described in § 32-18-1 shall be equipped with brakes acting on all wheels except as provided by §§ 32-18-3 to 32-18-6 , inclusive.
Source: SL 1967, ch 197, § 1 (c); SL 1968, ch 178, § 3.