Towns shall keep state aid highways cleared of snow during the winter season or such part of the year as the department may direct, so that they may be reasonably usable by motor vehicles. Snow on such state aid highways shall be removed to the outside edges of the shoulders of the road, and in a manner satisfactory to the department whose judgment shall be final. The towns shall sand the state aid highways to the satisfaction of the department, and in case the towns fail to sand the highways to the satisfaction of the department, the department shall be authorized to make arrangements for the proper sanding and the cost of such sanding done by the department shall be paid by the towns.   [PL 1981, c. 492, Pt. C, §12 (AMD).]