If lighting of a road, highway, or bridge is provided in accordance with section 19, the supervisor of the township shall exercise general supervision over the installing and maintenance of the lighting system, under the direction of the township board. However, if a road, highway, or bridge is situated in or between 2 or more townships, it shall be determined by the township boards which one of the township supervisors shall exercise supervision. The township board, or in case of roads, highways, or bridges located in or between 2 or more townships, then the township boards of the townships in or between which the road, highway, or bridge is situated, may contract for a period of time not exceeding 10 years with a person for furnishing the road, highway, or bridge lighting by artificial means, upon the terms and conditions as may be agreed.