Okla. Stat. tit. 19, § 1246

A. The board of county commissioners, in its discretion, may provide for the payment of the cost for improving streets, roads, intersections, alley crossings, or any part thereof, out of the county road fund. B. The Transportation Commission is authorized in its sole discretion to enter into agreements with the board of county commissioners of any county for participation with State Highway Construction and Maintenance Funds in the cost of any improvements on roads and streets which are a part of the state highway system, and such agreements may provide for the award and supervision of the contract by said county, the state's share of the cost to be due and payable upon completion of the project.