Whenever, in the judgment of the county executive, it is necessary for the safety or control of vehicular or pedestrian traffic, he is authorized to provide, by executive order, for the erection of "stop," "speed limit" and other traffic-control signs and devices on public streets, highways or other areas in the county; provided, that no such sign or device shall be erected on state highways without the approval of the state highway administration; and provided, that no such sign or device shall be erected at the cost of the county government in any incorporated town or special taxing area unless the council has by resolution consented to the payment of such costs; and provided, that if the private owner of any land used by the general public shall cause to have erected "stop," "speed limit" or other traffic-control signs or devices upon streets, highways and other areas within said private property said signs shall conform to the most recent edition of the "Manual on Uniform Traffic Control Devices for Streets and Highways" with regard to design, color, size and placement. The county executive is authorized to approve by executive order said traffic-control signs and devices, which shall then have the same effect as those public traffic-control signs and devices erected by the direction of the county executive; provided, that all such signs and devices on private property shall be constructed, erected and maintained at the cost of the owner of said land. (1978 L.M.C., ch. 7, § 2; 1981 L.M.C., ch. 40, § 2; 1984 L.M.C., ch. 24, § 36.)