Traffic Complexity Measurement under Higher Levels of Automation and Higher Traffic Densities

Abstract

An understanding of the complexity factors that affect controller workload under higher levels of automation for conflict detection and resolution and under higher traffic densities is critical for future operations. This paper examines traffic complexity variables under higher levels of automation where the human controller is still in the loop, but is being supported by advanced conflict detection and resolution automation. The study involved two conflict resolution automation modes (i.e., trial-planning automation and advisory automation) and three traffic densities (i.e., 1X, 2X and 3X). The results indicate that under the 1X traffic condition, controller workload was the lowest with advanced levels of automation. The complexity and workload increased progressively for the 2X and 3X traffic conditions. Results also showed that several variables such as horizontal proximity, aircraft density, separation criticality index, and two degrees of freedom indices appear to be relevant complexity measures for higher traffic densities. The degrees of freedom index for aircraft in conflict appears to be a relevant measure for higher levels of automation. Regression results show that automation resolution mode, number of aircraft, number of conflicts, separation criticality index, and degrees of freedom for aircraft in conflict represent complexity and correlate with controller workload under higher densities.