When the county commissioners travel in a body, or when two or more travel together, in the same vehicle not a common carrier only one shall be paid mileage.
The county commissioners may by an annual resolution, pool the mileage allowance as authorized by § 7-7-5 for each commissioner, and thereby authorize each commissioner to be paid his actual mileage expenses incurred, provided, however, that such total mileage expenditures for the fiscal year, for all commissioners shall not exceed the aggregate mileage expenses authorized by § 7-7-5.
SDCL 7-7-7