S.D. Codified Laws § 49-28A-3.3
If the United States Department of Transportation issues an official formal finding that one or more portions of § 49-28A-3, §§ 49-28A-3.2 and 49-28A-3.3, inclusive, may result in the loss of Federal Motor Carrier Safety Assistance Program funding, the Department of Public Safety may, by rule promulgated pursuant to chapter 1-26, implement the 2004 federal hours-of-service amendment as may be appropriate to preserve such federal funding.
If federal law or regulations are amended, or otherwise altered under law, at any time to cause to be exempted a class or group of vehicles, which class or group would include such gas or electric utility service vehicles within this state, from the hours-of-service requirements, any exemption shall be effective in this state immediately for the duration of the federal exemption.
SDCL 49-28A-3.3