(a) It is hereby declared that where in order to carry out the provisions of this chapter it is necessary that property rights be acquired, such acquisition is for a public purpose and is necessary for a highway purpose. The commissioner of transportation is authorized to acquire by purchase, gift or condemnation all advertising devices and all property rights pertaining thereto which are prohibited under the provisions of this chapter, and any rules promulgated pursuant thereto, provided that such advertising devices were in lawful existence on June 8, 1971. In any such acquisition, purchase or condemnation, just compensation shall be paid for:
- (1) the taking from the owner of such sign, display or device of all right, title, leasehold and interest in such sign, display or device; and
- (2) the taking from the owner of the real property on which such advertising device is located immediately prior to its removal or relocation, the right to erect and maintain thereon advertising devices, and full compensation therefor, including severance damage and damage to the remainder of the outdoor advertising plant regardless of whether it is located on property contiguous to or a part of that on which such sign is located, shall be included in the amounts paid to the respective owners. Provided, however, that no compensation shall be paid for severance damage and damage to the remainder of the outdoor advertising plant unless federal laws, or rules and regulations promulgated by the United States Department of Transportation provide for federal participation in the cost of such severance damage and damage to the remainder of the outdoor advertising plant.