Specification of route switching behavior reflecting reference alternative in long-distance travel: a case study in Korea

This study explores the effect of reference alternative in the decision concerning switching routes in long distance travel. In the choice context, it is known that drivers do not switch their current routes even if the travel times for the alternative routes are shorter within some range, which is called the indifference band. To reflect the range, we used an additional utility for the reference route in this study. Considering the property in long distance travel, we posit that the additional utility for the current route is necessary to reflect the role of the reference alternative, which is increasing in an intermediate range of remaining travel on the current route, while it is constant when the remaining travel is a short or long distance. To empirically defend the argument, the proposed specifications were estimated based on stated-choice data that were collected along Korean highways. The estimation results and the K-fold validation tests provided empirical findings that supported the argument. In addition, elasticities were obtained to discuss from a policy perspective.