Sahar Anvariazar - Faculty of industrial engineering and management systems Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
Mohsen Akbarpourshirazi - Faculty of industrial engineering and management systems Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
Behrooz Karimi - Faculty of industrial engineering and management systems Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran

The vehicle routing problem with divisible delivery and pick up and time window is a variant of basic vehicle routing problem where the vehicles serve delivery as well as pick up operations of the clients. In this case, customers can be visited twice, once for delivery and once for pick up services. This paper addresses a new mixed integer linear programming model, which considers greenhouse gases emissions as a soft constraint. The amount of emission is associated with physical features of each vehicle, such as the front surface and weight of vehicle. The objective of the model is to minimize not only the travel distance and number of available vehicles, but also to minimize the penalty of Co2 emission, which exceeds the greenhouse gases threshold. A new heuristic algorithm, which is hybrid of simulated annealing algorithm is proposed to solve the problem. Then, it is applied for solving Kalleh dairy company data. The numerical results are compared with the results of GA and PSO algorithms. Results shows that the value of objective function, which is gained by SA algorithm, is considerably lower than values gained by 2 other algorithms

delivery and pick up, Greenhouse gases, Soft time window, Vehicle routing problem, Kalleh dairy company