Scheduling Deliveries with Backhauls in Thailand's Cement Industry

Abstract

In this study, the Truckload Delivery with Backhaul Scheduling Problem (TDBSP) is formulated and an Ant Colony Optimization methodology developed for a related problem, the Vehicle Routing Problem with Backhaul and Time Windows (VRPBTW), is adapted for its solution. The TDBSP differs from the VRPBTW in that shipments are in units of truckloads, multiple time windows in multiple days are available for delivery to customers, limited space for servicing customers is available and multiple visits to each customer may be required. The problem is motivated by a real-world application arising at a leading cement producer in Thailand. Experts at the cement production plant assign vehicles to cement customers and lignite mines based on manual computations and experience. This study provides mathematical and computational frameworks for modeling and solving this real-world application.