Growth management in Washington State provides a new context for regional transportation planning. A major part of this planning involves investigation of the latest information processing techniques and interjurisdictional coordination specifically with regard to transportation and land use linkages. Geographic information system (GIS) applications for transportation can assist transportation planners with data analysis concerned with these linkages. This project has identified information needs in the context of a regional transportation planning process, particularly the needs of Regional Transportation Planning Organizations (RTPOs). Urban and rural contexts are considered. Information processing tasks are elucidated and the software functions that address these tasks are presented. Data sources are identified for urban and rural traffic forecast modeling. Institutional and technical barriers inhibiting access to data for the regional transportation planning process are discussed.