Health impact assessment (HIA) is a process whereby the health impacts of a proposed policy or program are systematically evaluated and summarized to inform decision-making. The objective of this project was to conduct an HIA of a proposed congestion pricing policy, which charged drivers in specific areas or roadways during heavy traffic periods, in downtown San Francisco, CA. Assessment of baseline community health conditions and forecasting of potential health impacts included Geographic Information Systems (GIS). Forecasting methods were used to study impacts on future pedestrian conditions, active transportation, vehicle collisions, air pollution, and other health related factors.