An attempt is made here to present a general model of mobility transition in developing societies that are undergoing a steady although imbalanced process of transformation. These societies are characterized by a sharp dualism in economy. They have a broad base of a traditional sector (pastoral nomadism and peasant economy) and a small highly localized modern sector in agriculture and industry.

Mobility transition is viewed here as transition of individuals and groups of people on the socio-economic ladder either spatially, temporally or both. In developing societies such a process ranges from transition within pastoral and peasant societies and between them, and from these sectors of the economy into the most modern sectors in agriculture and industry. Consequently we encounter two types of transition: a conservative one represented by transition within nomadism and the peasant economy, and an innovative one represented by mobility from this traditional sector into the modern sector.

Alternatively, mobility transition may be viewed as a process of transition from the local system represented by both nomadism and the peasant economy, into the regional system. Both constitute the complex national mobility transition (Symanski, Manners and Bromley, 1975).

The mobility transition so defined will be tested in North and Central Sudan as a step towards ascertaining its validity for similar areas.

Presentation of the general mobility transition model

Mobility transition in its three interrelated forms and types of local, regional and national systems is a function of a number of integrated variables with special characteristics in developing societies which distinguish them from developed societies.