This study aims to examine the temporal stability of individuals' stated preferences (SP) for modal choice, using panel data. SP surveys for the New Transit System, now under construction in Hiroshima, Japan, were carried out at three different points in time: 1987, 1988, and 1990. The data were analysed to identify within-wave and between-wave variations. The latter temporal variation was related to three causal factors: the different levels of travel service set up in the SP experiments, the change of individuals' characteristics, and other unobserved specific biases inherent in SP data. The effects of these factors were measured by developing the mode-choice models based on the stated-preference panel data. As a result, the levels of travel services and unobserved specific biases at each wave were found to affect significantly the temporal variation of the SP data. It was also shown that the relative importance of level-of-service variable in determining individuals' preference was temporally stable. (A)
Samenvatting