UNDERSTANDING VARIABILITY, HABIT AND THE EFFECT OF LONG PERIOD ACTIVITY PLAN IN MODAL CHOICES: A DAY TO DAY, WEEK TO WEEK ANALYSIS ON PANEL DATA

摘要

Understanding variability in individual behaviour is crucial for the comprehension of travel patternsand for the development and evaluation of planning policies. In the last 30 years a vast body ofresearch has approached the issue in a variety of ways, but there are no studies on the intrinsicvariability in the individual preferences for mode choices in absence of external changes (or shocks) inthe transportation infrastructures (i.e. introduction of new modes or major reorganization of thetransportation system). This requires using continuous panel data. Few papers have studied modechoice with continuous panel data but mainly focused on the panel correlation. In this work we use asix-week travel diary survey to study the intrinsic variability in the individual preferences for modechoices, the effect of long period plans and habitual behaviour in the daily mode choices. Mixed logitmodels are estimated that account for the above effects as well as for systematic and randomheterogeneity over individual preferences and responses. We also account for correlation over severaltime periods. Our results suggest that individual tastes for time and cost are fairly stable but there is asignificant systematic and random heterogeneity around these mean values and in the preferences forthe different alternatives. We found that there is a strong inertia effect in mode choice that increaseswith (or is reinforced by) the number of time the same tour is repeated. The sequence of mode choicemade is influenced by the duration of the activity and the weekly structure of the activities. Finally,models improve significantly when panel correlation is accounted for. But it seems that inertia canexplain to some extent for panel effect.