Oregon Revised Statutes Oregon Vehicle Code § 826.015

(1) For vehicles registered under ORS 826.031 or under proportional registration pursuant to ORS 826.009 or 826.011, the declaration shall contain the combined weight of the vehicle.

(2) For commercial buses, the declaration shall contain the unloaded weight of the vehicle plus the unloaded weight of any bus trailer to be used in combination with the vehicle. The declaration shall also indicate the number of persons, including the driver, to be carried in the vehicle, plus the number of persons to be carried on any bus trailer to be used in combination with the vehicle. For purposes of determining the fee for registration of the vehicle under ORS 803.420, the Department of Transportation shall determine the weight of the vehicle by adding the unloaded weight of the vehicle, plus the unloaded weight of any bus trailer to be used in combination with the vehicle, to a weight determined by multiplying the maximum seating capacity of the vehicle plus the maximum seating capacity of any bus trailer to be used in combination with the vehicle, including the driver's seat but excluding emergency seats, times 170 pounds, if the vehicle has a separate compartment for transporting baggage or express, or 150 pounds, if the vehicle has no separate compartment for transporting baggage or express. If the vehicle has a seating capacity that is not arranged for separate or individual seating, 18 lineal inches shall be deemed the equivalent of a passenger seat.