Attitude-Behaviour Relationships in Travel-Demand Modelling

A conceptual dynamic model of the relation between attitudes and travel choice (behaviour) can be developed which distinguishes between antecedent variables (characteristics of choice alternatives and of the commuter) and process variables (attitudes and perceived availablity constraints). While antecedent variables determine the process variables, the latter are in a complex mutual adjustment mechanism with behaviour. That is, attitudes determine and are determined by behaviour as a function of availability constraints. The effect of choice upon attitudes can be studied within the framework of the psychological theory of Cognitive Dissonance. The theory asserts that after an individual makes a choice between alternatives, he will align his stated attitudes to his choice, upgrading the satisfaction with both the positive and negative attributes of the chosen alternative and downgrading those of the rejected alternatives. The theory further asserts that the magnitude of these distortions (cognitive dissonance reductions) are a function of the importance of the attributes in the decision making process. Specific hypotheses covering the relation between travel mode choice and attitudes toward the modes can be derived from Cognitive Dissonance Theory. The first two hypotheses refer to individuals for whom there are no constraints on availabilities of the model alternatives; the hypotheses predict certain relations between attitudes, as a function of choices actually made. A third hypothesis relates attitudes to choice through the effect of perceived availatility constraints. Employing data from Ottawa, Canada, the hypotheses have been confirmed. The bidirectional attitude-choice causality should be used in providing transportation planning information. Attitudes, though affected by past behaviour, appear to be indicators of potential behavioural change when the availability and/or characteristics of choice alternatives change. Attitudes are therefore critical to development of innovative transportation concepts and effective communications to promote advantages of certain transportation alternatives. /Author/