Okla. Stat. tit. 69 § 1283
The Department may accept any allotment of funds by the United States, or any agency thereof, appropriated to carry out the purposes of federal law. The Department shall take such steps as may be necessary from time to time to obtain from the United States, or the appropriate agency thereof, funds allotted and appropriated, pursuant to said federal law, for the purpose of paying the federal share of the just compensation to be paid to sign owners and owners of real property under the terms of federal law and this act. In the event federal funds are not available for assistance in carrying out the provisions of the federal law, the Department may defer the removal of nonconforming signs until such time as federal funds are made available for such purpose.
Okla. Stat. tit. 69, § 1283