Vehicle routing problem and an application

Vehicle routing problem can be defined as to serve the people at the demand points by a heterogeneous/homogeneous fleet with the shortest paths under the constraints of capacity, time and cost. Vehicle routing problems have various extensions such as time windows, multiple vehicles, backhauls, simultaneous delivery and pick-up, etc. The objectives of all these problems are to design optimal routes minimizing total distance traveled, minimizing number of vehicles, etc that satisfy corresponding constraints. The costs associated with operating vehicles and crews for delivery purposes from an important component of total distribution costs. Consequently, small percentage of savings in these expenses could result in substantial total savings over a number of years. In this study, the main objective is to minimize total distance travelled by personnel shuttle buses. This is closely related to the exact locations and number of stops as well as the availability of alternative routes for each stop location. Therefore, from the modelling point of view, each stop is assigned to vehicles going to a specific direction. The routing problems as to how the assigned stops are travelled by each bus are solved by appling the solution procedure offered by VAM (Vogel?s Approximate Model).