Oregon Revised Statutes Highways, Roads, Bridges and Ferries § 366.572

(1) The Department of Transportation may enter into a cooperative agreement with any one or more cities, counties, road districts or other municipalities of the state for the construction, reconstruction, improvement, repair or maintenance of any state highway, and provide for an allocation of the cost of the project to the contracting parties.

(2) The Department of Transportation may enter into cooperative agreements with any county for the survey, construction, improvement, reconstruction, repair or maintenance of any state highway or part thereof upon such basis of contribution as may be agreed upon between them.