Intermodal Routing Model for Sustainable Transport Through Multi-objective Optimization

Abstract

To contribute to the sustainable development of transport and to the efficient mobility of people and goods, optimizing multimodal transport is a requirement. This paper presents a novel routing model for the optimization of intermodal one-way trips problems by considering multiple objective functions. The main goal of the developed model is to optimize simultaneously two objectives for intermodal routing, by having available several transport modes between a pair of nodes of a transport network. In the problem in study, the functions to minimize are: (1) the travel time between two nodes of a network; (2) the CO2 emissions, but additional objective functions may be considered. Furthermore, the model allows to have mandatory (or fixed) nodes and optional nodes, being the origin of the travel always a defined node. The destination may be a fixed node - defined destination, or any fixed node of the network - undefined destination. The mathematical formulation of the model leads to a multi-objective mixed binary linear program, and a classical scalarization method is performed to solve the problem. There is a lack of intermodal routing models in literature and specifically no multi-objective models on this matter were found. Therefore, as a sustainable transport both freight and passenger is a societal goal, the proposed model can be a valuable tool for transport managers. In terms of outcome, the developed program allows the decision-maker to choose from a set of Pareto solutions (corresponding to different weights of the objective functions in minimization) a suitable solution from the point of view of transport engineering. The computational experience included in the paper reveals the efficiency of the proposed model.