This chapter extends the material in Chapter 2 by providing a concise overview of the mechanics of the FSM (four-step model), illustrated with a hypothetical case study. The discussion in this chapter, however, focuses on US modelling practice. Transportation modelling developed as a component of the process of transportation analysis which came to be established in the USA during the era of post-war development and economic growth. Initial application of analytical methods began in the 1950s. The landmark study by Mitchell and Rapkin (1954) not only established the link of travel and activities (or land use), but also called for a comprehensive framework and inquiries into travel behaviour. The initial development of models of trip generation, distribution, and diversion in the early 1950s led to the first comprehensive application of the FSM system in the Chicago Area Transportation Study (Weiner, 1997) with the model sandwiched by land-use projection and economic evaluation. The focus was decidedly highway oriented, with new facilities being evaluated versus traffic engineering improvements. The 1960s brought federal legislation requiring "continuous, comprehensive, and cooperative" urban transportation planning, fully institutionalising the FSM. Further legislation in the 1970s brought environmental concerns to planning and modelling, as well as the need for multimodal planning. It was recognized that the existing model system may not be appropriate for application to emerging policy concerns and, in what might be referred to as the "first travel model improvement program", a call for improved models led to research and the development of disaggregate travel demand forecasting and equilibrium assignment methods, which integrated well with the FSM and have greatly directed modelling approaches for most of the last 25 years. The FSM is best seen as a particular application of transportation systems analysis (TSA), a framework due to Manheim (1970) and Florian et al. (1988), which positions the model well to view its strengths and weaknesses. A brief presentation of this TSA framework introduces the FSM context and leads to a discussion of problem and study area definition, model application, and data requirements. The models which are perhaps most commonly utilized in the FSM are then presented in the form of a sample application.
Samenvatting