Minimizing fleet operating costs for a container transportation company * Luca Coslovich a,b, † , Raffaele Pesenti c , Walter Ukovich a,b a Dipartimento di Elettrotecnica, Elettronica ed Informatica, Universit` a di Trieste, 34127 Trieste, Italy b Centro di Eccellenza per la Ricerca in TeleGeomatica e Informazione Spaziale, Universit` a di Trieste, 34127 Trieste, Italy c Dipartimento di Ingegneria Informatica, Universit` a di Palermo, 90128 Palermo, Italy Abstract This paper focuses on a fleet management problem that arises in container trucking industry. From the container transportation company perspective, the present and future operating costs to minimize can be divided in three components: the routing costs, the resource (i.e., driver and truck) assignment costs and the container repositioning costs (i.e., the costs of restoring a given container fleet distribution over the serviced territory, as requested by the shippers that own the containers). This real–world problem has been modeled as an integer programming problem. The pro- posed solution approach is based on the decomposition of this problem in three simpler sub– problems associated to each of the costs considered above. Numerical experiments on randomly generated instances, as well as on a real–world data set of an Italian container trucking company, are presented. Keywords: Transportation; Container trucking; Stochastic fleet management; Decomposition; Set covering problem 1 Introduction and problem statement A core problem faced by container trucking companies deals with a set of transportation orders at minimum cost. The essential decisions to be taken are: how to partition the set of transportation * The research described in this paper has been partially supported by C.N.R. (National Research Council of Italy) contracts 00.00333.ST74 and 00.00339.ST74, and by “Fondo Trieste – Progetti di ricerca scientifica e tecnologica – Anno 1998”. † Corresponding author. Tel.: +39-040-558-7134; fax: +39-040-558-3460. E-mail addresses: coslovic@units.it (Luca Coslovich), pesenti@unipa.it (Raffaele Pesenti), ukovich@units.it (Walter Ukovich).