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:
- 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.
- 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.
- 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.
- 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.
- 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.
- The frequency of shipments.
Intermodalism functions well when cargo flows need to be continuous and in
similar quantities.