Oregon Revised Statutes Cities § 221.333

(1) In all prosecutions for violation of motor vehicle parking ordinances in cities, it shall be sufficient to charge the defendant by an unsworn written notice if the notice clearly states:

(2) The notice provided for in subsection (1) of this section shall either be delivered to the defendant or placed in a conspicuous place upon the vehicle involved in the violation. A duplicate original of the notice shall serve as the complaint in the case when it is filed with the court. In all other respects the procedure now provided by law in such cases shall be followed, but ORS 810.365 does not apply. The officer or person authorized to issue a citation need not have observed the act of parking, but need only have observed that the car was parked in violation of city ordinances.