Oregon Revised Statutes Oregon Vehicle Code § 815.310

(1) The proof may be provided by any means that the Department of Transportation and the Environmental Quality Commission determine by joint rulemaking or by interagency agreement to be satisfactory.

(2) Except as otherwise provided in this section, when a certificate of compliance is used as proof, the certificate must comply with all the following:

(3) In order for registration to continue to be valid for a motor vehicle that is registered as a government-owned vehicle under ORS 805.040, a police undercover vehicle under ORS 805.060 or a state-owned vehicle with regular registration plates under ORS 805.045, the vehicle must be certified as frequently as a privately owned vehicle of the same registration type is required to be certified. For purposes of this subsection, the registration type of a privately owned vehicle is determined by the registration period for the vehicle under ORS 803.415. For local government vehicles, the proof of certification may be provided through self-testing facilities provided by local governmental agencies. Local governmental agencies providing self-testing facilities may not be charged a fee in connection with provision of the required proof. However, a reasonable fee covering department expenses in administering such self-testing programs may be charged.