BEHAVIOURAL THEORIES OF DISPERSION AND THE MIS-SPECIFICATION OF TRAVEL DEMAND MODELS

Conventional or first generation transport models have for some time been heavily criticised for their lack of behavioural content and inefficient use of data; more recently second generation or disaggregate travel demand models based on a theory of choice between discrete alternatives have also been viewed critically. First, it has been argued that implemented structures - and particularly the multinomial logit model - have not been sufficiently general to accomodate the "interaction" between alternatives; and second, and perhaps more importantly, that the underpinning theory, involving a perfectly discriminating rational man (Homo economicus), endowed with complete information is an acceptable starting point for the analysis of behaviour. In this paper the potential errors in forecasting travel response arising from theoretical misrepresentation are investigated; more generally, the problems of inference and hypothesis testing in conjunction with cross-sectional models are noted. A framework is developed to examine the consequences of the divergence between the behaviour of individuals in a system, the observed, and that description of their behaviour (which is embedded in a forecasting model) imputed by an observer, the modeller. The extent of this divergence in the context of response to particular stimuli is examined using Monte Carlo simulation for the following examples: (I) alternative assumptions relating to the structure of models reflecting substitution between similar alternatives; (II) alternative decision-making processes; (III) limited information and "satisficing" behaviour; and (IV) existence of habit in choice modelling. The method has allowed particular conclusions to be made about the importance of theoretical misrepresentation in the four examples. More generally, it highlights the problems of forecasting response with cross-sectionsl models and draws attention to the problem of validation which is all too often associated with the goodness of statistical fit of analytic functions to data patterns. (Author/TRRL)

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/01912615
• Corporate Authors:

  Pergamon Press, Incorporated

  Headington Hill Hall
  Oxford OX30BW,    
• Authors:
  • Williams, H C
  • Ortuzar, J D
• Publication Date: 1982-6

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 167-219
• Serial:
  • Transportation Research Part B: Methodological
  • Volume: 16B
  • Issue Number: 3
  • Publisher: Elsevier
  • ISSN: 0191-2615
  • Serial URL: http://www.sciencedirect.com/science/journal/01912615

Subject/Index Terms

• TRT Terms: Accuracy; Alternatives analysis; Behavior; Decision making; Demand; Disaggregate analysis; Forecasting; Human factors; Logits; Mathematical models; Monte Carlo method; Transportation; Travel; Travel behavior; Travel demand
• Uncontrolled Terms: Selection
• Old TRIS Terms: Disaggregate models
• ITRD Terms: 9001: Behaviour; 2248: Decision process; 285: Demand (econ); 132: Forecast; 2257: Human factor; 698: Journey; 6473: Mathematical model; 9072: Selection; 1155: Transport
• Subject Areas: Planning and Forecasting; Transportation (General); I72: Traffic and Transport Planning;

Filing Info

• Accession Number: 00362276
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Files: ITRD, TRIS
• Created Date: Nov 30 1982 12:00AM