Inventory routing problem for perishable products by considering social issue

Inventory Routing Problem (IRP) for perishable products is one of the complex subjects in IRPs. Moreover, considering other criteria and constraints, such as respecting time window, managing the amount of expired products, fuel consumption and environment and social criteria bring this problem more complex. This paper presents a new model considering economic and social aspects in IRPs. We study the effect of speed of vehicle in distribution of perishable products in IRPs. This consideration allows to reduce delivery time, impacting several economic criteria, but increase driver injury (risk of accident for driver), considerate in this model as social issues. In order to find a tradeoff between these issues, a new bi-objective mathematical model has been proposed. First objective focuses on traditional cost of inventory and distribution as well as age and price strategy, backorder cost and discount. Second objective function concerns in minimization of driver injury (social issue), calculated by considering the speed of vehicle in different existing paths between retailers. In fact, quicker path allows to decrease some costs but increase accident risk. It is noteworthy that other economic and social criteria can also add to proposed model. Finally, sensitivity analysis are performed to investigate the importance of each objective function as well as the effect of variation of inventory holding cost against profit and driver injury.