S.D. Codified Laws § 13-30-3
The amount of the transportation allowance is the rate established pursuant to § 3-9-1 per family for distances actually traveled in excess of five miles each way. No mileage may be paid for extra trips to the schoolhouse which the school board does not consider necessary nor for more miles than would be traveled if the shortest distance measured from the place on a publicly used road nearest the dwelling house of the child to the schoolhouse site were traveled. If children from more than one family are transported in the same vehicle mileage payments shall be paid to only one family. The school board may authorize additional miles if prior approval is obtained to facilitate cooperative efforts among families to share transportation duties. If children from more than one family are transported in a single vehicle, reimbursement shall be at rates established by the school board. However, the mileage reimbursement rate may not be less than the rate established pursuant to § 3-9-1. If, at the request of the parents, elementary children are assigned to a school that is further from the dwelling house than the nearest school, the board may limit the reimbursement to the mileage to the nearest school within the district. All claims for transportation allowance shall be filed with the school business manager not later than the close of the school fiscal year in which the travel for which reimbursement is sought actually occurred.
SDCL 13-30-3