Multicommodity vs. Single-Commodity Routing

In this paper we study a vehicle routing problem where customers request multiple commodities. We study the impact on transportation cost from using vehicles dedicated to a single commodity compared with using flexible vehicles capable of carrying any set of commodities. With vehicles that carry multiple commodities, we consider when the delivery to a customer can be made by more than one vehicle. If multiple vehicles can be used, we examine when deliveries of individual commodities may be split and when they may not be split. The latter problem has not previously been studied, and we present a mathematical programming model for it. We use worst case and computational analysis to compare these different models.