Transport Gateways and Hubs

In the emerging global geography of circulation, gateways and hubs are playing a crucial role:

Gateway. A location that promotes the continuity of a transportation system servicing supply chains. It is the interface between different systems of circulation and includes terminal facilities, but also the numerous linked activities such as distribution centers, warehouses and even insurance and finance. Gateways reap advantage of a favorable physical location such as highway junctions, confluence of rivers, seaboards, and have been the object of a significant accumulation of transport infrastructures such as terminals and their links. A gateway generally commands the entrance to and the exit from its catchment area and commonly imply a shift from one mode to the other (such as maritime / land). In other words, a gateway is a pivotal point for the entrance and the exit of goods in a region, a country, or a continent. The emergence of intermodal transportation systems reinforces gateways as major locations of convergence and transshipment and has modified their geography with increased locational flexibility. While major terminals have expanded and relocated to more peripheral locations, namely port facilities, many distribution centers have relocated even further away along corridors.
Hub. A central point for the collection, sorting, transshipment and distribution of goods for a particular area. This concept comes from a term used in air transport for passengers as well as for freight and describes collection and distribution through a single point such as the "Hub and Spoke" concept. A hub is thus the outcome of commercial decisions linked with a desired level of service in terms of frequency. System-wide the delays imposed by transshipments at the hub (instead of direct services) are compensated by higher frequencies of services between all points.

The transport system is subject to remarkable geographical changes even if many of its infrastructures are fixed. Flows, origins, destination and the modes used can change rather rapidly. What remains relatively constant are gateways, which can be seen as semi-obligatory points of passage, while a hub is a central location in a transport system with many inbound and outbound connections of the same mode. Gateways also tend to be most stable in time as they often have emerged at the convergence on inland transport systems while the importance of a hub can change if transport companies decide to use another hub, as common in the airline industry. Thus, gateways tend to be intermodal entities while hubs tend to perform transmodal (within a mode) operations.

Transport corridors are commonly linking gateways to the inland. The functions of centrality and intermediacy are particularly relevant to the emergence of a global nodal space since one focuses on nodes as an origin or destination of traffic while the other focuses on nodes as intermediate locations where transshipment is performed. While central locations obviously correspond to large metropolitan areas, intermediate locations have developed a rather unique geography.