Optimising the periodic distribution of gas cylinders with customers priority

This paper deals with a real-life application related to the distribution of gas cylinders to customers over a one-week horizon. Every customer should be served a pre-specified number of times during the week horizon. Customers are also characterised by a priority factor that expresses the importance of that customer to the company. Three heuristic methods have been develop based on a two-stage decomposition approach. The first stage assigns the customers to the service days and then, the second stage solves several VRPs, one for each working day. Several real-life experiments have been conducted to show that the heuristic that considers explicitly the customers priority performs well with respect to the other heuristics and also to the actual solution adopted by the company.