A novel multi-objective optimization model for production routing problem with sustainability dimensions

Production routing problem represents an important area of research in the field of supply chain coordination. Recently, researches on production routing problem are extended to consider environmental and social concerns in addition to traditional economic considerations. Due to the complexity of production routing problems, there is a limited body of research that successfully integrates all three dimensions of sustainability into these problems. To fill the existing gap, this study aims to propose a novel multi-objective model that integrates all three dimensions of sustainability. The proposed model involves three conflicting objectives: total operational cost, total emissions cost, and total social cost of accidents. Furthermore, this study compares two exact algorithms namely weighted sum and AUGMECON2 to generate Pareto optimal solutions. The AUGMECON2 method demonstrates a performance efficiency of 76.12 % for spacing metric, 15.32 % for inverted generational distance, and 15.99 % for mean ideal distance indicating its superiority over the weighted sum method in solving the sustainable production routing model. The results shows the trade-off between total operational cost and total social cost of accidents. This occurs because production in plants with higher setup and production costs but lower injury risk leads to higher social cost. Similarly, using larger-capacity vehicle to reduce fixed and fuel costs increases transportation risks for heavy loads. Furthermore, the results highlight a conflict between environmental and social objectives, with higher total emissions cost corresponding to lower and total social cost of accidents. By considering various policy implications, including balancing operational cost and social cost of accidents, incorporating emissions and safety standards, flexible inventory management, advancing technology, and enhancing data transparency and reporting, a more sustainable approach that integrates economic, environmental, and social objectives can be achieved.