TRANUS-J: Putting Large Models into Small Computers

Abstract

Traditionally, large integrated land-use and transport models require considerable amounts of computer resources, restricting their use to a small number of metropolitan or regional planning authorities and to an elite of consultancy firms. The increasing availability of microcomputers should be able to extend the use of models to a much larger community of planners. However, even the most efficient packages existing today cannot be fitted into the standard desk-top machines. The purpose of this paper is to describe a package for land-use and transport simulation for microcomputers, showing that this is not only possible, but also that there is no need to sacrifice detail or accuracy. Furthermore, the need to produce highly compact and efficient models has forced the research team to look for completely new algorithms and even new theoretical developments. In designing the models, economy of resources was also extended to data requirements, calibration, and evaluation, and considerable attention was devoted to making the models easy to handle and the results easy to interpret. The authors begin by describing the theoretical base of the models, briefly covering random utility, decision chains, and hierarchies. Next, a summary of the mathematical formulation is presented, finishing with a description of the operative characteristics of the computer programs and complementary features.