Sustainable vehicle-routing problem with time windows by heterogeneous fleet of vehicles and separated compartments: Application in waste collection problem

Abstract

The purpose of this study is solving a sustainable vehicle routing problem (VRP) which in this problem special features such as mixed close–open VRP, multi-depot VRP and some others which will be discussed in this section are considered for achieving closer to real life applications. Fleets of vehicle studied in this paper are heterogeneous and for each vehicle separated compartments with different capacity for each type of wastes is took into consideration. Vehicles have different limitation on traveling time, different fixed and variable cost and amount of pollutants that is emitted from them. For achieving a sustainable VRP economic, environment and society aspects should considered simultaneously which in this paper objective functions (1) to (3) respectively are about mentioned purposes; first one minimizes the cost of collecting wastes from customer's location, second one minimizes the pollutants which are emitted from vehicles while they are collecting wastes and finally third one minimizes violation from time limitations which are exist on each customer's location. A new mathematical mixed integer programming model is developed for solving this problem and problem is solved by CPLEX solver and augmented ɛ-constraint method. Moreover, AHP technique for making decisions is applied in order to help us to choose the best decision. Finally, sensitivity analysis is done on some important parameters.