The objective of this paper is to investigate the intra- and inter-individual heterogeneity of mode2 choice, when travel time is subject to variability. By “inter-individual heterogeneity” is meant that3 people are different in terms of attitude toward risk and have different functional forms for the4 utility function. By “intra-individual heterogeneity” is meant that the behavior may be different5 even when performed by the same individual when faced with a different transport mode. Based6 on RDUT, the paper shows that the probabilities of delay associated to train trips are overweighted7 and the probabilities associated to car trips are underweighted. A latent-class model offers a more8 contrasted view: if, overall, car users do indeed weight differently the probabilities for train and9 car trips, the train users seem to be risk neutral and consider the objective probabilities that are10 presented in the stated preferences survey.11