Sustainable supply chain network design with pooling

Faced with numerous operational and sustainability challenges, logistics systems require innovative solutions. Pooling logistics offers a practical solution by allowing resources to be shared and system performance to be improved. To better understand its potential, this study investigates a sustainable two-echelon supply chain network design (STESCND) model by comparing pooling and non-pooling scenarios under heterogeneous vehicle fleets. An optimization model based on mixed-integer linear programming (MILP) is developed, incorporating sustainability dimensions. To capture the full scope of sustainability, the model considers economic, environmental, and social dimensions, focusing respectively on cost minimization, reduction of CO2 emissions, and minimization of accident rates. The solution methodology is carried out in two stages. First, a mono-objective optimization is performed for each sustainability dimension separately. The results indicate that pooling can reduce total costs by 44% and 2 emissions by 49%, while affecting the accident rate by 11%. Second, a multi-objective optimization approach is applied using the ε-constraint method to analyze the trade-offs among the three dimensions. The multi-objective results show that this approach provides better-balanced solutions, providing valuable insights into the benefits of resource pooling and the inherent compromises between sustainability objectives.