Degradable transport network: Travel time budget of travelers with heterogeneous risk aversion

Empirical studies have suggested that travel time reliability plays an important role in travelers’ route choice behavior. This study develops an approach to relate the travel time variability due to stochastic network link capacity variations with travelers’ risk aversive route choice behaviors. We postulate that travelers acquire the variability of route travel times based on past experiences and factor such variability into their route choice consideration in the form of a travel time budget. This travel time budget varies with individuals and trip purposes and is related to the requirement on punctual arrivals. Moreover, all travelers want to minimize their travel time budgets. We formulate a multi-class mixed-equilibrium mathematical program to capture the route choice behaviors of travelers with heterogeneous risk aversions or requirements on punctual arrivals. Such an understanding has important implications on strengthening critical network links. This study then conducts numerical studies to illustrate its properties.