Mont. Code § 75-15-102
The legislature finds and declares that in order to promote the safety, convenience, and enjoyment of travel on and protection of the public investment in highways within this state and to preserve and enhance the natural scenic beauty or aesthetic features of the highways and adjacent areas, it shall be the policy of this state that the erection and maintenance of outdoor advertising in areas adjacent to the right-of-way of the interstate and primary systems within this state shall be regulated in accordance with the terms of this part and the rules promulgated by the commission pursuant thereto. It is the intention of the legislature in this part to provide a statutory basis for regulation of outdoor advertising consistent with the public policy relating to areas adjacent to the interstate and primary systems declared by congress in Title 23, United States Code, "Highways".
§ 75-15-102, MCA