A Process Model for Route Choice in Risky Traffic Networks

The accurate modeling of travelers’ route choice decision making when faced with unreliable (risky) travel times is necessary for the assessment of policies aimed at improving travel time reliability. Compared with econometric models, process models have not been investigated in travel decision making under risk. A process model aims to describe the actual decision making procedure and could potentially provide a better explanation to route choice behavior. A process model, the priority heuristic (Brandstatter et al. , 2006), is introduced to the travel choice context and its probabilistic version, the probabilistic priority heuristic (PPH) model, is developed in this study. With data collected from a stated preference survey, a rank-dependent expected utility (RDEU) model and two other alternative models are compared with the PPH model through cross validation. Results showed that the PPH model outperforms the RDEU model in both datafitting and predictive performances. This suggests that the process modeling paradigm could be a promising new area in travel behavior research. Major drawbacks of the PPH model include the discontinuity of the choice probability with respect to outcomes and associated probabilities, the limited applicability in situations where one alternative dominates or almost dominates the other, and the non-trivial extension to multiple-alternative situations. c © 2013 Hengliang Tian and Song Gao. Published by Elsevier Ltd. Selection and/or peer review under responsibility of Delft University of Technology