The county board of any county, as a part of its duties, shall have power and authority to contract for the installment, maintenance, and operation of road lighting systems, sufficient to light any county road, or any portion thereof in its county, when, in the judgment of the county board, the lighting of such road or any portion thereof is in the interest of public safety. The cost of installing, maintaining, and operating such road lighting systems shall be paid out of funds that are available for the construction and maintenance of county roads.