The Environmental Impact of Gateways and Hubs in International Air Transportation

Ohio State University, The, Columbus OH

Investigators

Abstract

International air transportation is fundamental to the integration of global economies. The ability to connect far flung cities depends on an elaborate system of airline interconnections. Geographers have long had an interest in describing and modeling the networks of links and the resultant levels of accessibility and their importance to global systems. Concepts such as hubs and gateways are in everyday use and indicate places that have developed special infrastructure to permit handling of long distance interactions. The purpose of this research project is to develop a linkage between the spatial organization of air networks and the possible implications of that structure for the environment. The project will examine the costs and benefits in variants of such arrangements: patterns that are often referred to as hub and spoke systems (which channel flows between major hubs) and point to point systems (which provide more convenient direct linkages). At base, the contrast between heavy flows between hubs and more direct but necessarily thinner flows between point to point pairs, poses a complex set of trade-offs. The purpose of this research project is to develop measures of the relative merits of alternative network arrangements. The project will examine the tension between efficient flows from a transport cost point of view, and the potential for such flows to impose rather heavy environmental impacts. The project will examine the fuel efficiency of various aircraft range and size configurations. The topic has ramifications for the location of hubs, and ultimately may have implications for the best way to select an air passenger fleet to accommodate the preferred patterns of interactions. The project aims to synthesize two contrasting views, one from the energy consumption of individual aircraft and the other from the overall network viewpoint. Research to date has tended to come at this problem from one side or the other and the research will develop an increased understanding of the interdependence between systems and their elements. To achieve the project's objectives, innovative linkages between operational and network efficiency points of view will be developed and tested in models of a simulated network. Because of the penetration of air transportation into everyday life, this project has several societal implications. The impacts of the project will range from educational ones to heightened awareness of the prevalence of economies of scope and scale in transportation. Specifically the results will provide a more complete understanding of the environmental and economic costs of air passenger interaction. The project will also bring the examination of fuel use and emissions more centrally into models of the operation and planning of air transport systems. The research will contribute to explanations of the ways that a hub serves as a focal point for interactions, and for models of diffusion which have implications for a range of application from improving airline security to understanding disease epidemiology. These topics have proven quite difficult to pin down quantitatively, and a transport network analysis will provide the tools to measure these elements in a spatial context. The project is likely to influence the way networks are assessed and measured.