Definition
REROUTE IMPACT ASSESSMENT (RRIA)
A capability within the Traffic Flow Management System that is used to define and evaluate a potential reroute prior to implementation, with or without miles-in-trail (MIT) restrictions. RRIA functions estimate the impact on demand (e.g., sector loads) and performance (e.g., flight delay). Using RRIA, traffic management personnel can determine whether the reroute will sufficiently reduce demand in the Flow Constraint Area and not create excessive “spill over” demand in the adjacent airspace on a specific route segment or point of interest (POI).
Source: FAA Pilot/Controller Glossary (verbatim from the Federal Aviation Regulations).