Glossary
Traffic Impact Analysis (TIA)
A study a jurisdiction requires once a project is expected to generate traffic above a set threshold, often triggering required road improvements.
A Traffic Impact Analysis models the traffic a proposed development will generate and its effect on surrounding roadways and intersections. Jurisdictions set a trigger threshold — commonly a trip-generation count — above which a TIA is required as part of site plan or subdivision approval. The output frequently includes required mitigation such as turn lanes, signals or roadway improvements, which land on the developer's budget and schedule. For industrial and truck-intensive uses the practical questions are often narrower: corner clearance, median status, and whether left turns in and out will actually be permitted. Thresholds and requirements vary by jurisdiction.