An Optimization Model for Vehicle Scheduling and Routing Problem

Vehicle scheduling has a significant impact on the logistic operations of businesses and effective scheduling can increase customer satisfaction. In this context, a vehicle scheduling model is developed to enhance the distribution operations of a company. The aim of the developed mixed-integer linear programming model is to minimize the number of vehicles departing in a day in order to decrease the extreme density that the company experiences on certain days. While designing the mathematical model, due date constraints have been taken into consideration. However, to propose better solutions, due dates are expanded one day, two days and three days respectively and the model is solved for each case. As due dates extended, the number of vehicles departing in a day decreased significantly. The model is solved using IBM ILOG CPLEX (OPL) software for seven days, and fifteen days periods by analyzing one month's data acquired from the company's database. As longer periods are optimized, the model generates better results. However, solution time increases.