Abstract:Urban models useful in transportation planning are reviewed, focusing especially on ones that are based on geographic information system (GIS) software. Then UPlan, a simple model written by the authors in the ArcView GIS, is described. Several different applications of UPlan are outlined, involving transportation planning and analysis of the growth-inducing effects of new facilities, to demonstrate its use. Such models are coming into use for National Environmental Policy Act of 1969 assessments and for joint land use and transportation planning.