Integrating GIS, simulation models, and visualization in traffic impact analysis

Planners have a long history of using Geographic Information Systems, simulation models and three-dimensional (3D) visualizations in research and practice projects. Although some have successfully integrated GIS and simulation modeling or GIS and computer visualization, few have met the challenge of integrating the three technologies into one system in order to support planning and decision-making. In an effort toward reaching this goal, a prototype traffic impact analysis system has been developed. Automobile traffic and travel speed are predicted with a volume/capacity ratio model. Carbon monoxide (CO) concentrations along roadways are calculated using the US Environmental Protection Agency's CAL3QHC model. GIS is used to prepare data and execute the models and present the modeling results in a geographic context. A series of 3D models of street segments and buildings along the highway are developed and subsequently integrated with simulation results to allow a geo-referenced 3D presentation, including animations of driving experiences. This study documents the benefits and challenges of integrating the technologies.