ABSTRACT
A large number of operational models have been described and show quite clearly the way the models have been applied in practice. Hybrid models have been developed largely in North America and have tended to be large comprehensive models which deal with highly disaggregated activities and simulate several sectors of the urban system. There are other models that have been developed specifically as large-scale hybrid models involving any number of theoretical and empirical relationships and using any form of mathematics thought appropriate. Operational urban models are developed to gain an insight into the nature of the urban system, particularly the relationship between land use activities, and then to predict the likely effects of certain future planning policies on the study region. It must always be remembered that urban models are a simplified mathematical representation of a part of the urban system.
