Simultaneous optimization of fuel surcharges and transit service runs in a multimodal transport network: a time-dependent activity-based approach

This paper addresses the simultaneous optimization problem of fuel surcharges and transit service runs for energy sustainability of multimodal transport network using a time-dependent activity-based approach. To model commuters' choices of trip chain, travel mode, departure time, route, and activity timing and duration over the times of a day, a time-dependent activity and multimodal travel choice equilibrium problem is first addressed and formulated as an equivalent variational inequality (VI) problem. A new model for optimizing the fuel surcharges and transit vehicle runs is proposed to maximize the total social net benefit of the multimodal transport system. The proposed model explicitly considers the interaction between the fuel surcharges and transit service runs and the commuters' activity-travel scheduling behavior. A heuristic solution algorithm is then developed to solve the proposed model. Finally, an illustrative example is given to show the application of the proposed model with various sensitivity tests. Insightful findings are presented with particularly the effects of the fuel surcharges and transit service improvement on the performance of the multimodal transport system in terms of the modal split, fuel consumption, and total social net benefit.