The director or any peace officer may order the driver of any vehicle previously weighed by a licensed public weighmaster to reweigh the vehicle and load at the nearest scale.
The director or any peace officer may order the driver of any vehicle operated by or for a retail merchant which vehicle contains hay, straw, or grain to weigh the vehicle and load at the nearest scale. If the weight is found to be less than the amount appearing on the invoice, a copy of which is required to be carried on the vehicle, the director or peace officer shall report the finding to the consignee and may prosecute such retail merchant in accordance with the provisions of this chapter.
RCW 15.80.440