Any State, county or city inspector of weights and measures who finds any commodity ready for or in process of delivery may inspect the commodity as to its weight and may direct the person in charge of the delivery of the commodity to convey the commodity to the nearest available scales operated by a weighmaster designated by the inspector. The inspector shall determine the gross weight of the commodity and the vehicle on which it is carried and shall direct the person in charge to return to the scales immediately upon unloading the commodity. Upon return of the vehicle, the inspector shall determine the weight of the vehicle without load and determine the net weight of the load delivered. The person in charge of a vehicle containing such a commodity or from which the commodity has been unloaded shall not fail to take the vehicle, upon the direction of the inspector of weights and measures, to the scales required in this section and shall not refuse to permit the commodity or vehicle to be weighed.