S.D. Codified Laws § 31-2-14
The salaries of the Transportation Commission, secretary of the Department of Transportation, engineer, deputies, assistants, and employees, their necessary expenses, the other expenses of maintaining the administration of the department, and the costs of maintenance and repair of highways shall be paid by the state treasurer from the state highway fund after the same have been duly appropriated from the fund by the Legislature and audited by the state auditor. State and federal highway funds necessary for construction of highways as defined in chapter 31-1 and purchase of rights-of-way and borrow pits pursuant to chapter 31-19, are hereby annually appropriated from the state highway fund. The amount of those funds expended for administrative purposes may not exceed seven percent of the available highway funds.
SDCL 31-2-14