Merge tree detection in a national-level air traffic simulation model

A simulation model of the United States (U.S.) National Airspace System (NAS) has been in use for several years, and is currently being improved. In the model, it was noticed that delay was not well-distributed for arrival flights. As a generalized solution, control points were algorithmically identified at air traffic flow merge points, since these points are typically the places where air traffic control (ATC) applies delay maneuvers to effect spacing. This paper describes the algorithm developed for the automatic identification of these points.