Delft University of Technology, The Netherlands
April 16, 2007, 11:00, Room GC C2 413 (click here for the map)
Choice sets of individual travellers play a paramount role in analyzing travel choice behaviour since size and composition of choice sets do matter in cases of choice model estimation and demand prediction. Incorrect choice sets (e.g. because of captivity) can lead to misspecification of choice models and to biases in predicted demand levels. The critical role of choice sets in choice modelling has given rise to profound research into choice set modelling in the transportation field, although largely confined to mode choice. We state that these insights gained on choice set modelling and choice set generation cannot simply be transferred to the route choice realm. For a variety of reasons the specification of route sets for route choice modelling is different and more complex, reason why this topic deserves special attention from researchers and practitioners. The talk will be devoted to a number topics related to the modelling and generation of route choice sets, specifically for application in large networks. In addition the talk investigates recent new approaches to choice set generation for large networks. The one group of promising approaches is the constrained enumeration procedures, often referred to as branch and bound techniques in the research field of road traffic assignment, or as rule-based assignment in the field of schedule-based assignment. Another promising line is combined stochastic (which may include several elements) and deterministic path search. We will summarize in what respect route choice sets differ from other travel choices implying that some proposed choice set modelling approaches cannot be adopted for routes. We will argue that it is necessary and advantageous to distinguish the processes of choice set formation and choice on the part of the traveller. We state that the different purposes of choice set generation, that is supply analysis, model estimation, and demand prediction do matter in choice set modelling. We present a generic conceptual scheme relating the distinct key elements inherent in each choice set generation approach.
Piet H.L. Bovy (1943) graduated as a civil engineer from the Technical University of Aachen (Germany). He completed his PhD at the Delft University of Technology on the subject of stochastic route choice modeling in networks. He gained his professional experience in various occupations such as at a German traffic consultancy firm, a university research institute at DUT, and the Dutch ministry of Transportation. Since 1993 he is full professor for Transportation Planning at the Delft University of Technology, Faculty of Civil Engineering and Geosciences, P.O. Box 5046, NL-2600 GA Delft, The Netherlands. email@example.com Education and research focus on transportation planning, travel behaviour analysis, transport modeling, and networks. Books on transportation to which he contributed are: Route Choice: Wayfinding in Transport Networks (Kluwer Academic Publishers, 1990) and A billion trips a day: Tradition and transition in European travel patterns (Kluwer Academic Publishers, 1993). Recently he edited a series of books on transport research at DUT such as on Motorway traffic flow analysis (Delft University Press, 1998), on Estimators of travel time for road networks (DUP, 2000), and on Modelling for transport systems planning (DUP, 2002). He has written numerous articles in top journals and conference proceedings (ISTTT, IATBR, TRB).