(a) The Department of Highways shall place and maintain such traffic-control devices, conforming to its manual and specifications, upon all state and federal highways as it shall deem necessary to indicate and to carry out the provisions of this act or to regulate, warn or guide traffic.
(b) No local authority shall place or maintain any traffic-control device upon any highway under the jurisdiction of the Department of Highways except by the latter's permission.
Laws 1961 P. 419, Sec. 15-105.