Or. Rev. Stat. § 801.055
(2) For purposes of the vehicle code, the weights of vehicles, combinations of vehicles, parts of vehicles, wheels or axles shall be determined by the use of methods, procedures and devices established by the Department of Transportation by rule. The rules established in accordance with this subsection may include any or all of the following:
[1983 c.338 §11; 1985 c.172 §1]