Source: Notteboom, T. and J-P Rodrigue (2005) “Port Regionalization: Towards a New Phase in Port Development”, Maritime Policy and Management, Vol. 32, No. 3, pp. 297-313.
The movement of empty trucks or containers represents one of the most complex transport problems in freight distribution. Acute imbalances in international trade have expanded the scale of this problem and even impacted on freight transport rates (transpacific rates are usually higher for eastbound flows than for westbound flows). Since transport systems are now more integrated, partially due to logistics, it becomes possible to cope more efficiently with this problem by minimizing empty movements through cargo rotation.
On the above figure, it is assumed that there are two inland locations, one which imports more than it exports (location A) and the other that exports more than it imports (location B). In a discontinuous system of supply flow management (for instance, each location is serviced by different transport companies), this situation would generate a large number of empty flows, namely from the import location back to the port terminal and then from the port terminal. However, by integrating the flows, it is possible to re-allocate empty flows from location A to location B and thus to improve the efficiency of distribution. However, this requires a marketplace where container demand can be reconciled with container supply.