
Source: adapted from Taaffe, E.J., H.L. Gauthier and M.E. O'Kelly
(1996) Geography of Transportation, Second Edition, Upper Saddle River,
NJ: Prentice Hall.
Corridor Development
The development of transportation networks commonly leads to the
creation of corridors. A model has been developed by Taaffe, Morrill
and Gould (1963) to explain this process. Although this model specifically
applies to empirical evidence derived from transport development in
West Africa, it can be applied elsewhere, such as in North America.
Six phases summarize the model:
- Phase A (Scattered ports). A set of small trade ports
are established along a coastline. They are connected to a wider
network of trade and provide access to locally supplied resources.
- Phase B (Penetration lines and port concentration). Trade
lines accessing the hinterland are constructed permitting the development
of new resources and/or markets. The ports to which they are connected
grow in proportion to the new traffic generated.
- Phase C (Development of feeders). The hinterland of penetrating
lines is further expanded by the development of feeders.
- Phase D (Beginning of interconnections). The transport
networks that have so far been developing independently gradually
become interconnected. Intermediate centers also start to emerge.
- Phase E (Complete interconnection). As the level of connectivity
increases, traffic tends to concentrate in the most connected ports
(often corresponding to the largest cities), implying that several
less well connected ports decline or disappear.
- Phase F (Emergence of high priority links). Economies
of scale favor the concentration of the traffic along the most efficient
links, supporting the emergence of transport corridors. Links having
lower volumes can even be closed down. The regional transport system
has thus reached a phase of maturity and the structure of the network
is unlikely to change unless of significant economic or technological
developments.