Flow-based formulations for the Mixed Capacitated Arc Routing Problem – Lower bounds

Mixed Capacitated Arc Routing Problem (MCARP) models arise in distribution or collecting problems where activities are performed by vehicles, with limited capacity, and are continuously distributed along some predefined links (routes, streets) of an associated network. Considering directed as well as undirected required links, it is a generalization of the well known Capacitated Arc Routing problem (CARP). A compact flow based and valid model for the MCARP is presented. Due to its large number of variables and constraints we develop an aggregated version of this model. Although not valid, its linear programming bound coincides with the linear programming bound of the original model. During the presentation, computational experiments will be reported.