ORS 823.015

The service or delivery of any notice, order, form or other document or legal process required to be made by the Department of Transportation in connection with any statute governing motor carriers or railroads may be made by mail. If by mail, service or delivery is made when the required material is deposited in the post office, in a sealed envelope with postage paid, addressed to the person on whom it is to be served or delivered, at the address as it last appears in the records of the department.