Integrated Freight Transport Systems: Intermodal and Transmodal Connectivity
Connectivity is of core importance in contemporary freight distribution as it is concomitantly an intermodal and a transmodal activity. In integrated transport systems the time component has become increasingly significant. Since modal speed improvements tend to be marginal, it is at the terminal that most of the time and cost benefits are achieved. Connectivity is more than an intermodal activity, it also concerns movements within segments of the same mode. As supply chains became longer and more complex, the pressure on intermodal and transmodal transportation increased. In this geography connectivity linking different parts of the transport systems, freight markets and freight forwarders are interacting with increasing efficiency. Intermodal connectivity (managing flows between modes) have received the bulk of the attention:
  • Transloading facility. An intermodal terminal enabling the transfer from road to rail transport systems. In North America, they are commonly labeled as intermodal yards or terminals.
  • On-dock rail. An intermodal terminal enabling the transfer from maritime to rail transport systems.
  • Port container yard. An intermodal terminal enabling the transfer of cargoes from maritime to road transport systems. Many port terminal facilities
Transmodal connectivity (managing flows within the same mode) have received less attention, the main reason being that until recently they mainly took place within fragmented and regulated national transport systems. The main transmodal dimensions include:
  • Transmodal road. Mainly takes place at distribution centers, which have become strategic elements in freight distribution systems. It is probably one of the few cases where connectivity can be combined with added value activities, such as labeling and packaging. Although distribution centers were conventionally warehousing facilities in which commodities could be stored while waiting to be sold to customers down the supply chain, this function has substantially receded. Time constraints in freight distribution impacted on road based distribution centers, whose function is increasingly related to transmodal connectivity and much less to warehousing. The true time-dependent transmodal facility remains the cross-docking distribution center.
  • Transmodal maritime. Ship-to-ship connectivity mainly concerns transshipment hubs such as in the Caribbean, the Mediterranean or ship-to-barge activities. Although in many cases the containers are actually unloaded onto a temporary storage facility (commonly next to the piers), an off-shore hub is functionally a transmodal facility. They have emerged at intermediary locations by offering transshipment advantages in view of costs related to pendulum multiport services coupled with lower container handling cost, in addition to economies of scale for feeder ships.
  • Transmodal rail. Most rail systems were built to service specific markets and were heavily regulated. It is only recently that deregulation and containerization created the need for transmodal functions in rail transport systems, since rail transportation was "forced" to address a new variety of movements, many of them with international origins or destinations. Initially, rail developed greater intermodal efficiencies with maritime and road transport systems, particularly because this represented new market opportunities.
  • Transmodal air (not shown). The development of global air freight networks involving long distance air hauls supported the setting of transmodal air hubs. Like air passengers hubs, their setting is the outcome of the decision of cargo airlines about how to route their freight considering its origins and destinations, the level of demand and the technical limitations of aircrafts in terms of range and capacity.