When the secretary of transportation determines that the topography of the land adjoining the highway, road or street will not permit adequate screening of any junkyard lawfully in existence, or the screening of such a junkyard would not be economically feasible, the secretary shall have the authority to acquire by gift, purchase, exchange, or condemnation, such interests in lands as may be necessary to secure the relocation, removal or disposal of the junkyards; and to pay for the costs of relocation, removal, or disposal, thereof. When the secretary determines that it is in the best interest of the state the secretary may acquire such lands, or interests in lands, as may be necessary to provide adequate screening of such junkyards.