A rich heterogeneous fleet vehicle routing problem with flexible time windows: a case study of dairy supply chain

Abstract

Routing is a particularly important concept of cargo transport and has always enticed the interest of researchers and decision makers from different industries. The rich vehicle routing problem considers more realistic features of the real-world problems than the conventional problem. This article aims at solving a vehicle routing problem with heterogeneous fleet and flexible hard and soft time windows where flexible time windows allow for early and tardy deliveries in a given tolerance interval considering earliness and tardiness penalties through defining the earliness and tardiness as decision variables. In this paper, the proposed mathematical programming model is verified through several numerical examples using GAMS software. In order to demonstrate the applicability of the model, a real-world case study is provided. The results show the high potential of the proposed model for real-life application. Specifically, by applying the results of the case study, a 156,000 USD annual cost reduction is possible.