Stability requirement in a weekly waste collection problem

Based on a practical study in a local authority, this paper deals with a study on a new criterion for a weekly waste collection problem to consider the stability of proposed routes. In the problem under consideration, some parts of the network must be collected once a week (at the beginning of the week) and some parts twice a week (at the beginning and at the end of the week); for a week there are then two waste collection problems to solve. Each of them is modeled as a VRP with time windows. To solve this weekly waste collection problem, we propose several two-steps heuristic methods: first one computes one set of routes with usual criteria (cost) and secondly one computes the other set of routes by adding a new criteria for taking into account the stability between the two sets of routes. Then, we provide an experimental comparison of the proposed methods on VRPTW instances.