An approach to the asymmetric multi-depot capacitated arc routing problem

Despite the fact that the Capacitated Arc Routing Problems (CARPs) received substantial attention in the literature, most of the research concentrates on the symmetric and single-depot version of the problem. In this paper, we fill this gap by proposing an approach to solving a more general version of the problem and analysing its properties. We present an MILP formulation that accommodates asymmetric multi-depot case and consider valid inequalities that may be used to tighten its LP relaxation. A symmetry breaking scheme for a single-depot case is also proposed. An extensive numerical study is carried to investigate the properties of the problem and the proposed solution approach.