After decades of intensive research on the vehicle routing problem (VRP), many highly efficient single-objective heuristics exist for a multitude of VRP variants. But when new side-objectives emerge-such as service quality, workload balance, pollution reduction, consistency-the prevailing approach has been to develop new, problem-specific, and increasingly complex multiobjective (MO) methods. Yet in principle, MO problems can be efficiently solved with existing single-objective solvers. This is the fundamental idea behind the well-known -constraint method (ECM). Despite its generality and conceptual simplicity, the ECM has been largely ignored in the domain of heuristics and remains associated mostly with exact algorithms. In this article, we dispel these preconceptions and demonstrate that -constraintbased frameworks can be a highly effective way to directly leverage the decades of research on single-objective VRP heuristics in emerging MO settings.
KEYWORDS box algorithm, epsilon-constraint, metaheuristics, multiobjective, vehicle routingThis is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.