Before any cattle guard and gateway may be erected across any highway or section line as authorized in section 24-10-01, the board of county commissioners or board of township supervisors, as the case may be, shall approve written specifications of the cattle guard and gateway. Specifications approved by the board of county commissioners must be filed with the county auditor and specifications approved by the board of township supervisors must be filed with the township clerk. The specifications must include requirements for warning signs to be placed approximately three hundred feet [91.44 meters] from and plainly visible to persons approaching the cattle guard upon the highway or section line. A cattle guard must be so constructed as to permit the passage of motor vehicles through and over the same. No cattle guard may be erected upon any highway or section line unless there also is provided adjacent thereto an ample gateway in which must be erected a gate which may be opened easily and closed by the public. The person who applied for permission to erect the cattle guard shall maintain the cattle guard and gateway, unless application is otherwise assigned. Within the limits of an enclosure so completed by authorized cattle guards erected in accordance with such specifications, livestock must be permitted to run at large without liability for being upon the highway or section line.