(a) The rights-of-way provided for all state highways shall be held inviolate for state highway purposes, except as provided in subsections (b) and (c) of this section. No physical or functional encroachments, installations, signs other than traffic signs or signals, posters, billboards, roadside stands, gasoline pumps, or other structures or uses shall be permitted within the right-of-way limits of state highways.
(b) Political subdivisions, rural electric cooperatives, rural telephone cooperatives, private television cables, and public utilities of the state may use any right-of-way or land, property, or interest therein, the property of the State Highway Commission, for the purpose of laying or erecting pipelines, sewers, wires, poles, ditches, railways, or any other purpose, under existing agreements or permits or such agreements or permits hereinafter made by the commission or under existing laws, provided that such use does not interfere with the public use of the property for highway purposes.
(c) No private television cable shall be placed upon the right-of-way limit of any state highway until such person, firm, association, partnership, or corporation first executes a bond payable to the commission in an amount to be determined by the district engineer located in the district in which such cable is to be located.