（American University of Beirut 講師，MIT-ITSプログラム研究員）
講演タイトル：Attitudes and Value of Time Heterogeneity
概要：There is ample evidence showing a high level of heterogeneity of values of time among travelers. Previous studies have represented this heterogeneity by a distribution such as lognormal whose parameters depend on covariates like income, trip purpose, and mode of travel.
We present and demonstrate a model where the distribution of the value of time also depends on attitudes towards travel. Attitudes are latent, or unobservable, and their distribution determines the conditional distribution of the value of time given the observable covariates such as income. We illustrate this model using data from a stated preferences survey. The estimation results show that as expected the median value of time increases with income and that the variability of value of time also increases with income reflecting the greater effect that the attitude towards travel has for high income groups.