Integrated Transportation Network Design Optimization

Traditionally, the design of a transportation system has focused on one of the two sys-tems that comprise the transportation architecture, the vehicle or the network design.However, to dene a systems level architecture for a transportation system, it is neces-sary to expand the system denition during the design process to include the networkdenition, the vehicle architecture, and the operations, which couple the vehicle and thenetwork. In this paper, the transportation architecture is decomposed into these fundamen-tal sub-systems by classifying the decisions required to dene each sub-system. Utilizingthe integrated transportation system formulation, the design of the transportation archi-tecture can be obtained by concurrently optimizing the vehicle and network decisions. Byformulating the problem in this manner, the optimization can exploit the coupling betweenthe vehicle and network denition to nd a system-level solution that best satises the sys-tem objective. The case study presented in this paper focuses on the design of an aircrafttransportation network for overnight package delivery. By concurrently optimizing boththe vehicle and network denition for a selected few cities with a xed demand, we obtaina minimum of a ten percent improvement in cost over that obtained by optimizing thenetwork design using a set of pre-dened aircrafts. Additionally, by comparing the concur-rently optimized solutions with the solutions obtained by traditional vehicle optimization,a minimum of an eleven percent improvement in cost is realized. The improvement insystem cost obtained by the integrated transportation optimization implementation can beattributed to the reduction in operational ine–ciencies for the transportation system.