Optimizing High-Speed Rail and Air Transport Intermodal Passenger Network Design

How does one quantitatively analyze intermodal passenger systems? Can high-speed rail links reduce costs to airline services? A method for analyzing transportation networks that involve more than one mode is presented. With intermodal costs considered in detail from both the operator and the traveler aspects (including time costs and service benefits and negative costs), optimal network designs that reduce overall costs for both stakeholders are created. As a case study, the potential impact on optimization of transportation network design for air and high-speed rail travel around the Iberian Peninsula in southwestern Europe is examined. Key aspects of the model design and assumptions, including the sparse and contrasting intermodal valuations used, weighting of the cost components, and the cost to implement intermodality are evaluated. The optimization procedure, using a linear Boolean mathematical program, shows that the benefits of intermodality are best captured when a more holistic intermodal product is offered, and that high-speed rail becomes progressively less competitive as traveler costs rise and there is a discernible shortage of traveler valuations of intermodal service attributes.