Effect of captive riders in intercity mode-choice modeling

Abstract

The primary objective of this study is to investigate the effect of including captive riders in modechoice modelling for intercity travel in Saudi Arabia. To achieve this objective, mode-choice models were calibrated and validated using the intercity travel data of Saudi Arabia. The calibration process was carried out in three stages. In the first stage, mode-choice models were calibrated using the data of choice riders only, the choices being those alternatives as stated by the travellers. In the second stage, modechoice models were calibrated assuming full choices over all the alternatives available by the choice riders. Finally, in the last stage of model calibration, captive riders were included in the travel dataset. The calibrated models were compared with respect to their coefficient estimates and other goodness-of-fit statistics.

It was found from the study that the inclusion of captive riders in mode-choice models resulted in increased significance of the coefficient estimates which is mainly due to the increased sample size but decreased the overall fit of the models. When used for prediction purpose, only that model which was calibrated with choice riders data was capable of predicting the mode-choice of the travellers correctly whereas, the model calibrated with choice riders plus captive riders was unable to predict the modechoice of the intercity travellers correctly.