Sense and Sensibility -Sources of Uncertainty and Ambiguity Attitudes of Individual Commuters

There is growing attention to the complex patterns of uncertainty attitudes in the traffic context. For example, people may choose a transport mode, route, or departure time based on their attitudes towards the travel time uncertainty associated with these choices. Existing studies often assume that travellers treat travel time uncertainty as risk, meaning outcomes with a known probability distribution. However, it is rare for travellers to have precise information about the probability distribution of the network. In reality, travellers often face ambiguous travel times, with unknown probability distributions. In this study, we develop a novel framework for understanding uncertainty attitudes in the transport context to investigate decision-making under uncertainty for commuting, which involves day-to-day repeated situations.

In this paper, we focus on the role of ambiguity attitudes in transport mode choice. We hypothesise that people’s attitudes towards travel time uncertainty are source-dependent — for example, some people may be more averse to the ambiguities in a car trip than in a public transport trip, or vice versa. Our experiment design consists of a baseline group and two treated groups: one with additional information from historical travel times and another considering a commute trip from participants' real-life experiences. We identify the role of the following distinctive aspects in the decision-making process under travel time uncertainty: (a) how people perceive uncertainties (e.g., ambiguity-induced insensitivity) and (b) whether and to what extent people like or dislike ambiguity (e.g., ambiguity aversion, neutrality, or seeking). Furthermore, our results provide insights into whether and how these aspects are linked to transport mode preferences.