The use and misuse of simplified approaches in travel forecasting.

Simplified models for travel forecasting and policy analysis are used in two different ways; namely (i) as the one and only tool for analysis; especially in small urban areas where input data are usually approximate. Considering the scope and use of the models in those applications, the time and expense of developing a sophisticated model is usually not warranted (Hartgen, 1969); (ii) as a "first cut" analysis (sketch planning) tool to screen out the clearly infeasible alternatives, with more sophisticated models to be used at a later stage. This paper will look at selected aspects of these simplified models. (A)