Extending Vehicle Routing by Collaboration and Sub - contraction : Experiments for the estimation of the efficiency improvement

Transportation planning requires both, decisions on the choice of transport resources and decisions on the deployment of the chosen resources. Therefore, transportation orders must be assigned to resources for fulfillment while the operations for the usage of each resource have to be planned. Most freight forwarding companies have to cope with a strongly fluctuating demand on the transportation market which varies considerably over time. Aside from these market-fluctuations they have to manage the daily variations of their volume of orders. Therefore , freight forwarding companies have to ensure that enough resources will be provided. On the other hand, the fixed costs of the own vehicle fleet force to reduce the number of own vehicles since it makes no sense for a forwarder to provide enough transportation capacity capable to cover the peaks of a volatile volume of orders. A rigorous reduction of the own fleet size is mostly profitable because it allows the so called cherry-picking which means to perform only the most suitable requests in a very efficient manner by self-fulfillment. But cherry-picking does not really make sense unless the remaining requests are fulfilled in a cost-efficient way as well. Usually, only a part of the upcoming requests is fulfilled by own transportation resources. The remaining part of requests is either fulfilled by entrusting external freight carriers (subcontracting) or by exchanging requests within a coalition of collaborating forwarders. These two different approaches for " external freight fulfillment " result in specific extensions of the common planning problems for vehicle routing. Besides the possibility to fulfill additional requests which would otherwise exceed the own transportation capacity, the approaches for external freight fulfillment can be used to improve the quality of transportation planning. The efficiency of transportation planning can be increased drastically by extending the usual vehicle routing and scheduling problems by the possibilities of collaborative planning and of subcontracting. Both types of problem extension transform the usual vehicle routing and scheduling problems to more general operational transportation problems. In this contribution, we analyze the motivation, the chances, the realization, and the challenges of the general operational transportation planning problems obtained by the above extensions. We report on experiments for combining several isolated vehicle routing problems of single partners to a