Modeling traveler's route choice criteria under uncertainty

This paper examines the differences between the travel time budget (TTB) model (Lo and Luo, 2004) and the reliability-based stochastic user equilibrium (RSUE) model (Shao et al., 2005). These two models are aimed to model travelers' route choice criteria under uncertainty. The TTB model studies the travel time variations caused by exogenous sources in terms of predetermined link capacity variations with a given travel demand. It is postulated the travelers would acquire the route travel time variations based on past experiences, and take such variations into their route choice consideration in the form of a travel time budget. On the other hand, the RSUE model explores the travel time variations arising from endogenous sources which are dependent on the variations of travel demand. It can further be extended to incorporate the travelers' perception errors in their route choice behaviors. In order to clearly distinguish the essential differences between these two models, numerical examples are presented together with discussion of the key findings.