Computerized policy analysis models have a long history of use. In most cases, however, they are designed to be used only by quantitative analysts, and their outputs are not directly understandable by policymakers and members of their staffs. Advances in information technology have resulted in "work station" models with interactive human-machine interfaces. This paper describes a decision support system, GO-FORWARD, that integrates visualization with a spreadsheet transportation policy analysis model developed by RAND/EAC for the Dutch Ministry of Transportation, Public Works and Water Management. Besides presenting the technical aspects of the system (e.g., hypermedia and GIS capabilities), the paper also addresses the added value that the system can provide for policy analysis and policymaking.