Measuring the Impact of Airspace Restrictions on Air Traffic Flow Using Four-Dimensional System Fundamental Diagrams for Urban Air Mobility

Abstract

To ease urban congestion, advanced air mobility (AAM) proposes the use of small aerial vehicles at low altitudes for uses such as package delivery and passenger services. In a developed state, an AAM service is predicted to involve thousands of trips daily, creating much higher densities of aircraft than currently exist in any airspace. Airspace structures have been proposed to help manage the high-density aircraft traffic. One such airspace structure is tube airspace, in which vehicles fly along predefined paths at specified altitudes. Tube airspaces have the advantage of aligning vehicle trajectories to reduce conflicts, however, traffic flow through restricted tube airspaces is not yet well understood. This paper defines how to measure traffic flow in a restricted network of airspace. These definitions are applied to measure traffic flow in several simulated scenarios of tube airspace constructs. By analyzing and comparing the macroscopic traffic flow patterns of tube airspace, several insights about the benefits and drawbacks of tube airspace are found. The results of this paper could improve decisions about creating and managing tube airspaces, and therefore would be of interest to AAM network planners and operators. They are also of interest to aviation researchers who could use these scenarios and findings to study further AAM services in airspace.