This study is concerned with the search for a truly behavioural explanation of the choice of travel mode within the urban context. It therefore concentrates on the quality of the data inputs used in modal choice models and the role accorded to modal choice in various transportation packages, plans and strategies. The poor predictive capabilities of most disaggregate mode choice behavioural models is attributed partly to the neglect of the impact of home and work location decisions, and car purchase decisions, on the subsequent choice of work trip travel mode.
Chapter One articulates the nature of the modal choice problem and provides some insights into the present state of mode choice analysis debate. Most commentators are in agreement on the need for an a priori causal hypothesis to explain modal choice behaviour.
To give theoretical perspective to the analysis and critical review of modal choice models, Chapter Two examines the genesis and subsequent development of the main psychological hypotheses underlying neo-classical utility theory.
In Chapter Three, some of the major conceptual problems that confront the modal choice analyst are critically examined. Particular emphasis is given to the valuation of time savings debate.
In Chapter Four, a review of a representative selection of the most frequently cited works on the topic of third generation mode choice models is undertaken. The manner in which these models adapted the neo-classical theory is a particular focal point.
Chapter Five presents an analysis of the various elasticity co-efficients estimated in a selection of studies. The finding that travellers are quite insensitive to moderate changes in both time and cost of car and public transport, for work trips, seems surprising since both travel cost and time are consistently ranked as the two most important determinants of rnodal choice. These findings dontrast with the highly successful performance of first generation demonstration projects that successfully captured patronage from previous car users, without dramatic changes in either costs or travel time. This anamoly provides• the central thesis of this study, that by concentrating solely on the work trip and reducing modal choice to the car/transit dichotomy, researchers and• transportation planners alike have erroneously conceived of the line-haul segment as the basis for competition between the private car and public transport. They ignored the horne-end and work-end access/egress segments of the door-to-door operation, the vital segments where the car had little or no competition from public transport. Despite the much higher valuations ascribed to excess travel time (walking, waiting, and transfer time), it was not until the late sixties that demand activated door-to-door public transport services began to successfully invade the domain hitherto dominated by the private car. Chapter Five, then, is the synthetic chapter of the thesis.
Chapter Six provides an evaluation of Australian Capital City Transportation Planning and a Critique of Australian model choice research.
Chapter Seven discusses the trend towards citizen involvement and less rigid stressing, in particular, the important role of attitudinal surveys in the new, more eclectic approach. Some definitional clarification of modal choice attributes and a more useful classificatory schema for designing questionnaires is suggested. Some psychological approaches towards mode choice behaviours are discussed.
The methodology adopted in the study takes the form of a critical theoretical review from a standpoint that conceives of modal choice as being a multi-disciplinary phenomenon.