Intermediate Facilities in Freight Transportation Planning: A Survey

Consolidation of freight and merging operations are essential for transportation companies to reduce costs and improve the level of service provided to customers. Such operations take place in intermediate facilities or terminals located between the origins and the destinations of freight. This survey reviews the main contributions from the operations research literature on freight transportation planning problems where the presence of intermediate facilities has a strong impact on the cost of the system and on how goods are delivered. In particular, we focus on the tactical planning issues arising in this context. We have identified three classes of problems with intermediate facilities: vehicle routing problems, transshipment problems, and service network design problems. For each class of problems we provide an overview of the main problem variants, survey the methods used for their solution, and indicate open research directions.