S.D. Codified Laws § 49-28A-3.1
Qualified intrastate drivers under age twenty-one
Notwithstanding the provisions of § 49-28A-3 , any person under the age of twenty-one but over the age of eighteen may become a qualified intrastate driver if the person is certified as a private applicator pursuant to § 38-21-23 .
Source: SL 1988, ch 374; SL 2009, ch 238, § 1.