Evolutionary Algorithms for Stochastic Arc Routing Problems

The Capacitated Arc Routing Problem (CARP) is a combinatorial optimization problem in which vehicles with limited capacity must treat a set of arcs in a network, to minimize the total cost of the trips. The SCARP is a stochastic version with random demands on the arcs. The management rules used for instance in waste collection enable to derive mathematical expressions for objectives like the expected total cost. A memetic algorithm (MA) for the SCARP is proposed and compared with two deterministic versions based on average demands. All solutions are evaluated by simulation, to see how they are affected by random fluctuations of demands. This evaluation confirms the expected cost computed by the MA and shows its ability to provide robust solutions, without significant enlargement of the cost of planned trips.