S.D. Codified Laws § 32-12A-22
License endorsements
The endorsements to a commercial driver license shall be as follows:
(1) T --Double/triple trailers;
(2) P --Passengers;
(3) N --Tank vehicles;
(4) H --Hazardous materials;
(5) X --Combination tank vehicles and hazardous materials; and
(6) S --School bus.
Source: SL 1989, ch 267, § 17; SDCL § 32-12-97; SL 2001, ch 171, §§ 89, 115.