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Track: Transportation, Logistics Planning
William Thomas
COMSIS Corporation
8737 Coleville Road Suite 1100
Silver Spring, MD 20910
Telephone: 301-588-0800
Fax: 301-588-5922
E-mail: thomasb@comsiscorp.com
Tony Hoffman
Using Geographic Information in Travel Demand Model Network Development
Defining Issue: The accuracy of travel forecasts produced by a travel demand model is governed significantly by the quality and accuracy of network data used in model development (such as link distances and the positioning of centroids and connectors). Better accuracy could be achieved if compiled geographic information (such as TIGER or the National Transportation Atlas Database) were utilized. This is difficult if travel demand model networks cannot be maintained in the same coverage that contains the geographic information. Moreover, today's transportation planning requirements often require integration of environmental, resource, and travel demand model network data to facilitate alternatives analysis. GIS Solution: COMSIS Corporation has developed capabilities within MINUTP (a PC-based highway and transit transportation forecasting software) to easily develop and maintain travel demand model networks in ArcView, a popular GIS "desktop" software. Methodology: MINUTP networks can now be transferred
back and forth between a set of shapefiles that can subsequently be imported into ArcView. This process allows for transportation networks maintained in ArcView to be updated with variables from a MINUTP network. In this way transportation networks can be maintained in a GIS environment, exported to MINUTP for travel demand model execution, and then updated, based on information generated by the model execution. Network conflation is also supported in this process via a set of equivalency points. Software: This application is composed of two parts: a shapefile translation utility for MINUTP networks and a set of tools that facilitate editing of the converted networks in ArcView. The translation utility was written in C as a separate module packaged with MINUTP. The ArcView tools were written in Avenue and aid the analyst that is not familiar with ArcView software's editing procedures. The tools closely mimic those used by MINUTP's network editor. This paper describes the application and the considerations
involved in its development.
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