Managing vehicle breakdown incidents during urban distribution of a common product

This paper addresses a case in which a vehicle, member of a fleet distributing a single product, is immobilized while executing its distribution plan. Some active vehicles of the fleet are then rerouted to serve selected clients of the immobilized vehicle. We model this re-planning problem as a variation of the Team Orienteering Problem constraining all vehicle routes to an upper time, or distance, limit, and taking into account limited vehicle capacity. We propose an efficient heuristic to provide solutions in almost real-time. The heuristic progressively constructs new routes for each active vehicle, which may load additional product by visiting the warehouse or the immobilized vehicle. If appropriate, we solve this replenishment sub-problem by a fast labelling algorithm. We test the effectiveness of the proposed heuristic by comparing its solutions with those obtained by an appropriate Genetic Algorithm (GA) that yields high quality (but computationally expensive) results.