Okla. Stat. tit. 69, § 69-1731: Letting of contracts for turnpike construction

All contracts for the construction of turnpikes shall be let by

the Authority to the lowest responsible bidder, or bidders, after

notice by publication in the same manner as provided in Section 1101

of this Code, provided, the Authority may reject all bids and

readvertise the same. Furthermore, the Authority shall retain five

percent (5%) of the total amount of money due under contract with

the Authority for payment of taxes and providing of workers'

compensation insurance as provided in Section 1103 of this Code.