Any bridge or culvert, or both, that has been constructed, repaired or maintained by adjoining counties may be abandoned and the use thereof for road purposes discontinued if the county boards of such adjoining counties determine by concurrent resolution that:
(1) the bridge or culvert, or both, proposed to be abandoned is unsafe for the use of traffic and is in need of extensive repair or replacement, but the amount of traffic making use of such structure or structures is so small that the expense of repairing or replacing the structure or structures cannot be justified;(2) other means of access between the counties are available to adequately serve traffic in the area served by the bridge or culvert, or both, proposed to be abandoned;(3) it will be in the best interest of the majority of the residents of each county to abandon the use of such bridge or culvert, or both; and(4) an agreement has been reached as to the share of the cost of removal of any bridge so abandoned that is to be borne by each county, which agreement shall be set out in the resolution. Whenever the use of any bridge is abandoned under the provisions of this Section such bridge shall be promptly removed and the watercourse over which it passed left unobstructed.