Iowa Code § 327D.15: Continuous shipments.

It shall be unlawful for any common carrier subject to the provisions of this chapter to enter into any combination, contract or agreement, expressed or implied, to prevent, by change of time schedules, carriage in different cars, or, by other means or device, the carriage of freights from being continuous from place of shipment to the place of destination in the state; and no break of bulk, stoppage, or interruption made by such common carrier shall prevent the carriage of freights from being treated as one continuous carriage from the place of shipment to the place of destination, unless such break, stoppage, or interruption was made in good faith for some necessary purpose, and without any intent to avoid or unnecessarily interrupt such continuous carriage, or to evade any of the provisions of this chapter.