Optimal Vehicle Routing for Parcel Delivery with Considering Two Time Periods

In city logistics, some group of vehicles are usually assigned a certain fixed areas so that drivers get used to the route or the customer sites. Vehicles deliver materials regularly every time period at the same area. In other words, the customer demand can be placed in the similar area each time period. Thus, we may find the optimal route for the demand of two time periods instead of finding the optimal route for the single time period. This paper proposes a mathematical programming model for the vehicle routing problem for the parcel delivery in urban transportation with considering two time periods. Since the area of delivery is the same, the integration of demand of two time periods can reduce the total transportation costs.