Oregon Revised Statutes Highways, Roads, Bridges and Ferries § 381.270

Competitive bids shall be invited for the construction of any bridge mentioned in ORS 381.260 in conformity with the plans, specifications and design. The call for bids shall require that each bidder accompany the bid with a certified check or a bidder's bond or an irrevocable letter of credit issued by an insured institution as defined in ORS 706.008 in the amount of not less than five percent of the amount of the bid. The contract, if awarded, shall be awarded to the bidder adjudged to be the lowest and best, responsible bidder. Any and all bids may be rejected and refused if it appears to be the best interest of the general public.