In all counties of the second class the county commission may provide and supply the sheriff and deputy sheriffs of the county with such number of police cars or motor vehicles as the said county commission shall determine to be necessary for the efficient performance of the duties of the office, but the number shall be not less than one motor vehicle for each fifteen thousand inhabitants or part thereof in counties of the second class containing all or part of a city of more than eight thousand inhabitants, and shall be not less than one vehicle for each five thousand inhabitants in all other counties of the second class. The motor vehicles provided may be of any make or size as determined by the county commission.