This project is an ongoing, long-term research effort on developing methodologies to estimate the annual amount and shipment frequency of Extremely Hazardous Substances (EHS) that are regularly transported on Oklahoma roadways. These estimations are used to model EHS flows and conduct an incident risk assessment associated with such EHS transportation. This information would be a valuable input to the state’s Local Emergency Planning Commissions (LEPCs), First Responders, and Health Services in their planning for possible emergencies.