Or. Admin. R. 734-082-0055 – Approved Routes for Authorized Combinations of Vehicles

(1) The Chief Engineer, or a designee, may approve, limit or delete by written order the state highways or sections of state highways approved for use by vehicles authorized by OAR Chapter 734, Division 82.
(2) The Chief Engineer may also specify the type(s) of vehicle combinations authorized on approved routes.
(3) The list of approved highways and types of vehicle combinations authorized are maintained by the Chief Engineer.
(4) Trial test runs may be required to revise routes or approved vehicle combinations.
(5) Before adding or deleting highways or sections of highways, the Chief Engineer shall investigate the condition of the highway, and may consider road surface width, condition, safe passing opportunities, bridges, structures, accessibility, general sight distance, and other conditions deemed appropriate along such highways.

ORS 183.335(5) & 818.200

ORS 818.220 & 818.225