S.D. Codified Laws § 3-9-1.1
If an Office of Fleet and Travel Management or Department of Transportation pool motor vehicle is available within ten miles of a person's place of residence or headquarters station but the person uses a privately owned vehicle instead for state business, the mileage reimbursement rate is forty-five percent of the standard mileage rate for business authorized by the United States Internal Revenue Service as of October first each year.
The Office of Fleet and Travel Management must approve mileage reimbursement paid at the rate set pursuant to § 3-9-1 if there are Office of Fleet and Travel Management or Department of Transportation pool motor vehicles available within ten miles of a person's place of residence or headquarters station.
This section does not apply to elected officers, departmental secretaries, and chairs of state boards and commissions.
SDCL 3-9-1.1