Load balancing in the mail sorting process: a case study at the French postal company La Poste

Emmanuelle Amann (), Arnaud Laurent and Nasser Mebarki ()
Additional contact information
Emmanuelle Amann: LS2N - équipe CPS3 - Conception, Pilotage, Surveillance et Supervision des systèmes - LS2N - Laboratoire des Sciences du Numérique de Nantes - Inria - Institut National de Recherche en Informatique et en Automatique - CNRS - Centre National de la Recherche Scientifique - IMT Atlantique - IMT Atlantique - IMT - Institut Mines-Télécom [Paris] - Nantes Univ - ECN - NANTES UNIVERSITÉ - École Centrale de Nantes - Nantes Univ - Nantes Université - Nantes univ - UFR ST - Nantes université - UFR des Sciences et des Techniques - Nantes Université - pôle Sciences et technologie - Nantes Univ - Nantes Université
Arnaud Laurent: LS2N - équipe CPS3 - Conception, Pilotage, Surveillance et Supervision des systèmes - LS2N - Laboratoire des Sciences du Numérique de Nantes - Inria - Institut National de Recherche en Informatique et en Automatique - CNRS - Centre National de la Recherche Scientifique - IMT Atlantique - IMT Atlantique - IMT - Institut Mines-Télécom [Paris] - Nantes Univ - ECN - NANTES UNIVERSITÉ - École Centrale de Nantes - Nantes Univ - Nantes Université - Nantes univ - UFR ST - Nantes université - UFR des Sciences et des Techniques - Nantes Université - pôle Sciences et technologie - Nantes Univ - Nantes Université
Nasser Mebarki: LS2N - équipe CPS3 - Conception, Pilotage, Surveillance et Supervision des systèmes - LS2N - Laboratoire des Sciences du Numérique de Nantes - Inria - Institut National de Recherche en Informatique et en Automatique - CNRS - Centre National de la Recherche Scientifique - IMT Atlantique - IMT Atlantique - IMT - Institut Mines-Télécom [Paris] - Nantes Univ - ECN - NANTES UNIVERSITÉ - École Centrale de Nantes - Nantes Univ - Nantes Université - Nantes univ - UFR ST - Nantes université - UFR des Sciences et des Techniques - Nantes Université - pôle Sciences et technologie - Nantes Univ - Nantes Université

Post-Print from HAL

Abstract: This paper investigates a load balancing problem within the context of postal sorting operations at La Poste, the French postal service. Faced with declining mail volumes, La Poste must reorganize its processes to maintain service quality and operational efficiency. Mail sorting is modeled as a Simple Assembly Line Balancing Problem (SALBP-2), where mail items (tasks) are assigned to containers (stations) in a way that minimizes load imbalances while respecting precedence constraints. These constraints take the form of independent chains, as each mail route follows a fixed delivery sequence. We propose three resolution methods: an exact approach based on a Mixed Integer Linear Programming (MILP) formulation, a metaheuristic algorithm based on simulated annealing, and a fast heuristic designed for industrial deployment which exploits the precedence constraint structure for faster convergence. The metaheuristic and the heuristic are tested on academic and real-world datasets much larger than those commonly used in the literature. In order to use them several times a day, the resolution method needs to be fast in terms of calculation time. Due to its strong performance and low computation time, the heuristic we propose has been implemented on industrial platforms at La Poste and is now used daily.

Keywords: post; Mail sorting; load smoothing; balancing; optimization; MILP; assembly line; heuristic (search for similar items in EconPapers)
Date: 2026
Note: View the original document on HAL open archive server: https://hal.science/hal-05409410v1
References: Add references at CitEc
Citations:

Published in International Journal of Production Research, 2026, ⟨10.1080/00207543.2025.2592799⟩

Downloads: (external link)
https://hal.science/hal-05409410v1/document (application/pdf)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:hal:journl:hal-05409410

DOI: 10.1080/00207543.2025.2592799

Access Statistics for this paper

More papers in Post-Print from HAL
Bibliographic data for series maintained by CCSD ().