2015 ORS § 366.305¹
Materials, supplies and equipment

The Department of Transportation may select the materials to be used in the construction, maintenance and operation of state highways. It may purchase or contract for, independent of any particular job, improvement or highway project, whether done by contract, force account or otherwise, any material, supplies or equipment deemed necessary for carrying out the provisions and purposes of this Act in such amounts and manner and pursuant to such method as in the judgment of the department will be for the best interests of the state.