National Center for Sustainable Transportation

The current freight transportation network is highly unbalanced as routing decisions are made by individual users without coordination. Certain routes may become congested when chosen based on current traffic information without any anticipation that if other users do the same, these routes are no longer the best. This project developed a centrally coordinated load balancing system that considers all user demands and generates individual routes that balance freight loads across the network by minimizing cost. It is initially assumed that all vehicles are diesel and then gradually increases zero emissions vehicles such as electric trucks for a mixed fleet of trucks. The electric trucks add additional constraints due to limitation of range and charging time of batteries. As the number of electric trucks increases, the emissions reduce as expected; however, the cost of charging does not make their use less operational costly than the corresponding diesel trucks. The experiments show that for electric trucks to compete with diesel, charging should occur when drivers are off duty or in idle mode since the cost of charging is mainly due to the labor cost of the waiting driver. Several simulation experiments show the benefits of deploying electric trucks in a freight fleet with respect to environment and operational cost, provided charging is scheduled appropriately. It is shown that the proposed centrally coordinated load balancing system can easily incorporate different concepts such as the empty container re-use where the exchange of containers between users can be optimized to reduce empty trips. In order to better understand the implementation issues of a load balancing system, the report also includes results from interviews of individuals responsible for trucking operations in the Los Angeles region. All interviewed trucking companies are either drayage operations (hauling freight to and from ports or intermodal facilities) or short-haul operators that move goods between manufacturers, distribution center, and retail facilities. The answer for load balancing system varies between interviewees and it is recommended to follow an iterative fashion by first targeting trucking companies who already work collaboratively in associations and vertical markets. These clusters of firms have built working relationships, engage in communication, and have trust between members.

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