Taaffe, Morrill and Gould (TMG) Model

Taaffe, Morrill and Gould, in 1963, undertook a comparative analysis of the development of transport in developing countries and they were able to show that certain broad regularities permitted “a descriptive generalization of an ideal typical sequence of transportation development”.

Their spatial model of transport network development in developing countries has proved to be a valuable help in the understanding of transport development and has been widely applied. The model which Taaffe and his colleagues devised was based upon Ghanaian and Nigerian experience, but it has been found to be applicable to other developing lands, for example, in Latin America.

TMG Model

Taaffe et al. identified six stages in their sequence of transportation development. Figure 3.3 illustrates the sequential stages in the evolution of the transport network. The first stage consists of scattered settlements and small ports along a coast, which arose from colonial occupation. Such coastal settlements developed trading functions, though in the beginning these were of a very limited nature and, in consequence, their hinterlands were very restricted.

Furthermore, there was little lateral inter-connection between the scattered settlements, except for those effected by native fishing craft of occasional trading ships. The second stage evolved slowly but gradually as lines of inland penetration developed and some of these which linked up mining settlements or centers of population became more important than the others.

With the emergence of these major lines of penetration, often linked to the best located of the coastal ports, port concentration begins to develop and these commence to grow at the expense of their neighbors, some of which eventually disappear as trading centres or at best linger on as relict ports. This second stage goes on, hand in hand with the growth of an efficient administrative system and, more particularly, with the expansion of production for export.

The third stage is marked by the development of ‘feeder’ routes which focus more particularly upon the main ports and the more important centres in the interior. At the same time, as the growth in the export trade stimulates economic expansion generally in the hinterland, a number of intermediate centres begin to develop along the major access routes. In the fourth stage, these intermediate centres begin to develop into nodes which become focal points for feeder networks of their own.

The beginnings of lateral interconnection also takes place with lands between the major ports and the major inland towns being affected. Stage five sees the emergence of complete interconnections as the various feeder networks grow around the ports, major inland centres and main-line nodes and begin to link up.

Finally, in stage six, as the economy becomes more developed and integrated, all the principal centres and many of the minor centres are linked together in the transport system, while a number of high priority trunk routes develop which link the largest or most important centres.