Transport costs and the dynamics of population redistribution : two strategic models for the south east

In Britain, and in the other major industrialised countries, a significant redistribution of urban population is taking place. Metropolitan.conurbations are losing population and employment to the surrounding regions, resulting in the rise to urban status of many smaller freestanding towns, and the decline of inner city areas as dominant centres of employment and population. This 'postsuburbanisation' phase of urban development has given rise to the expansion of the metropolitan hinterland, with long commuting distances, while simultaneously the cities are no longer performing their traditional role as attractors and 'seed-beds' of new jobs. The availability of played a major part process. Transport of the metropolitan central role of the of transport has in recent years been icance-by the_rising cost of energy cost of transportaccompanied by the redistribution of jobs within regions new patterns of urban development and relatively cheap transport has always in the population redistribution supply, while assisting the expansion labour market area, also weakens the conurbation. This balancing function given added significance. The resulting continuing could result in perhaps lead to,the reversal of present trends. Existing analytical methods are inappropriate for " exploring these dynamic and interactive processes. Conventional techniques are based on static frameworks;_ with highly disaggregated variables atfa fine spatial scale. Such methodologies do not reflect the interactive nature of urban processes, and they necessarily constrain the planner to a limited number of not widely different alternatives. This study is an attempt to shift the emphasis in urban modelling from the detailed description of structure to a broader description of the processes at work. This necessarily involves an explicitly dynamic modelling methodology, which is more appropriate to the description of rapid change. Two dynamic frameworks framework based on the using continuous time, framework based on the theory, using discrete calibrated for the decentralisation of increase in commuting that has taken place between 1961 and are developed: one is a theoretical logistic growth of an urban area, and the other is a modelling accounting mechanism of kinetic time. Both of these models are South-East, and describe the population from Greater London and the 1976. A range of urban policies involving transport pricing, job and housing supply are tested on these' models, and the resulting population distributions and ı commuting flows demonstrate .the usefulness to policy makers of such broad brushiprocess-descriptive models The theoretical and model1ing'frameWorks presented in this study can potentially be developed into methodol that are complementary to_existing comprehensive transportation - land use models, but at a strategic planning level