Analyzing the Trade-Off between Minimizing Travel Times and Reducing Monetary Costs for Users in the Transit Network Design

The efficiency of the planning process in public transport is represented through different measures, which are practically impossible to optimize simultaneously. This study defines a bi-objective optimization problem for the transit network design to analyze the trade-off between minimization of travel times and reducing monetary costs for passengers (which was not addressed in the literature). Indeed, the minimization of monetary costs is relevant in transport systems without a complete integrated fare system, where passengers may pay for each trip-leg, and this factor is essential when referring to the systems’ accessibility. To achieve our goal, we implement an epsilon-constraint algorithm capable of obtaining high-quality approximations of the Pareto front for benchmark instances in hours of computational time, which is reasonable for strategical planning problems. Numerical results show that the conflict between both objectives is evident, and it is possible to identify the more useful lines to optimize each objective, which is relevant information for the decision-making process