Fixed routes with backup vehicles for stochastic vehicle routing problems with time constraints

We propose a practical and flexible fixed routing system that preserves many of the benefits of traditional fixed routes but can be deployed in settings with medium to high variability and delivery time window constraints. The key ideas are the introduction of a new recourse strategy, in which customers are assigned to two planned routes, a primary and a backup, and recourse decisions can move customers to backup routes to regain feasibility or improve costs, and the use of sampling-based techniques to handle the presence of delivery time windows during the construction of primary and backup routes. A computational study based on real-life data demonstrates the efficacy of the proposed fixed routing system and the route construction techniques. © 2009 Wiley Periodicals, Inc. NETWORKS, 2009