The Nature of Intermodalism

History as well as competition between modes has tended to produce a transport system that was segmented and un-integrated. Each mode, particularly the carriers that operated them, has sought to exploit its own advantages in terms of cost, service, reliability and safety. Carriers try to retain business and increase revenue by maximizing the line-haul under their control. All the modes saw the other modes as competitors, and were viewed with a level of suspicion and mistrust. The lack of integration between the modes was also accentuated by public policy that has frequently barred companies from owning firms in other modes (as in the United States before deregulation), or has placed a mode under direct state monopoly control (as in Europe). Modalism was also favored because of the difficulties of transferring goods from one mode to another, thereby incurring additional terminal costs and delays, mainly because the load unit needs to be changed, which is common for bulk transportation.

Since the 1960s major efforts have been made to integrate separate transport systems through intermodalism, which took place in several stages, first with the setting of maritime networks which then better connected with inland networks. From a functional and operational perspective, two components are involved in intermodalism:

Intermodal transportation. The movements of passengers or freight from one mode of transport to another, commonly taking place at a terminal specifically designed for such a purpose. In North America, the term intermodal is also used to refer to containerized rail transportation.

Transmodal transportation. The movements of passengers or freight within the same mode of transport. Although "pure" transmodal transportation rarely exists and an intermodal operation is often required (e.g. ship to dockside to ship), the purpose is to insure continuity within the same modal network.

What initially began as improving the productivity of shipping evolved into an integrated supply chain management system across modes and the development of intermodal transportation networks.

Intermodal transportation network. A logistically linked system using two or more transport modes with a single rate. Modes are having common handling characteristics, permitting freight (or people) to be transferred between modes during a movement between an origin and a destination. For freight, it also implies that the cargo does not need to be handled, just the load unit such as a pallet or a container.

This involves the use of at least two different modes in a trip from an origin to a destination through an intermodal transport chain, which permit the integration of several transportation networks. Intermodality enhances the economic performance of a transport chain by using modes in the most productive manner. Thus, the line-haul economies of rail may be exploited for long distances, with the efficiencies of trucks providing flexible local pick up and deliveries. The key is that the entire trip is seen as a whole, rather than as a series of legs, each marked by an individual operation with separate sets of documentation and rates. This is organized around the followings concepts:

1. The nature and quantity of the transported cargo. Intermodal transportation is usually suitable for intermediate and finished goods in load units of less than 25 tons.
2. The modes of transportation being used. Intermodal transportation is organized as a sequence of modes, often known as an intermodal transport chain. The dominant modes supporting intermodalism are trucking, rail, barges and maritime. Air transportation usually only require intermodalism (trucking) for its "first and last miles" and not used in combination with other modes. Additionally, load units used by air transportation are not readily convertible with other modes.
3. The origins and destinations. Distances play an important role as the longer the distance, the more likely an intermodal transport chain will be used. Distances above 500 km (longer than one day of trucking) usually require intermodal transportation.
4. Transportation time and costs. Intermodalism tries to use each mode according to their respective time and cost advantages so that total transport costs are minimized.
5. The value of the cargo. Suitable for intermediate cargo values. Low and high value shipments are usually less suitable for intermodal transportation. High value shipments will tend to use the most direct options (such as air cargo) while low value shipments are usually point to point and relying on one mode such as rail or maritime.
6. The frequency of shipments. Intermodalism functions well when cargo flows need to be continuous and in similar quantities.