Miss. Code Ann. § 63-3-303: Miss. Code Ann. § 63-3-303

The commissioner of public safety and the state highway commission shall place and maintain such traffic-control devices conforming to its manual and specifications, upon all state and county highways as it shall deem necessary to indicate and to carry out the provisions of this chapter or to regulate, warn, or guide traffic.

No local authority shall place or maintain any traffic-control device upon any highway under the jurisdiction of the commissioner of public safety and the state highway commission except by the latter's permission.