A Macroscopic Air Transportation Capacity Model: Metrics and Delay Correlation

Summary

The need for a macroscopic air transportation modeling approach is discussed and a recently developed model is applied to the U.S. air transportation system. The new model is designed to estimate the maximum capacity of a national air transportation region. The model is based on empirically observed aircraft arrival rates, government published annual operational rate statistics, and analytically derived airport arrival/departure functions. The underlying premise is that the air transportation system can be modeled as a multi path, steady state network of queues, whose maximum capacity is the sum of the maximum airport operational rates, less airspace human factors limitations. Capacity is defined to be twice the hourly arrival rate (since departures equal arrivals in equilibrium). The validity of the model predictions is tested by: 1) observing reported airport delay values ranked in order of model estimated maximum capacity utilization; and 2) observing historical operational growth rates for airports that are now operating near predicted maximum capacity. A national capacity value is estimated and compared to observed historical and predicted growth rates. All planned runway additions are included in the national capacity estimate and a growing national capacity shortfall is predicted. It is estimated that the US is currently operating at 57% of maximum capacity and will be at 70% national capacity by 2010. It is observed that significant delays begin at about 50% capacity fraction and grow at a hyperbolic rate. The effect of adopting new technology and operational concepts is shown to have a better impact on capacity growth (i.e. up to 30%) than runway construction (i.e. 1% per runway). This work should be of interest to policy makers who are responsible for making investments in national and/or local air transportation systems and for those responsible for measuring the air transportation systems operational capacity.