Proceedings of the 2007 Mid-Continent Transportation Research Symposium, Ames, Iowa, August 2007. © 2007 by Iowa State University. The contents of this paper reflect the views of the author(s), who are responsible for the facts and accuracy of the information presented herein. Review of Demand Modeling Methodologies for Air-Related Transportation: An Institutional Challenge to Intermodalism Xiubin Wang National Center for Freight and Infrastructure Research and Education University of Wisconsin, Madison 2205 Engineering Hall 1415 Engineering Drive Madison, WI 53706-1691 wangx@engr.wisc.edu Lei Yu Department of Transportation Studies Texas Southern University Technology Building 125 3100 Cleburne Avenue Houston, TX 77004-9986 yu_lx@tsu.edu ABSTRACT Fundamental to intermodal development is consistent demand modeling across the intermodal system, which coordinates resource allocation. However, different planning organizations are responsible for the development of different components of the intermodal system. In the case of air transportation, air demand modeling is mainly conducted by Federal Aviation Administration and commercial airlines for air traffic control and air flight operations. Airport-related surface demand modeling is undertaken primarily by airport authorities and metropolitan planning organizations for airport design and urban planning. These agencies adopt different methodologies from different perspectives, and there is an institutional gap between the methodologies, which may undermine the well being of the intermodal transportation system. In this paper, methodologies for demand modeling in the airport-related intermodal transportation system are reviewed, and the relevant problems are identified. The authors highlight a great need for a consistent demand modeling in support of intermodalism. Key words: air demand modeling—intermodal transportation—urban planning