The United States Air Traffic Control (ATC) system is designed to provide for the safe and efficient flow of air traffic from origin to destination. The Federal Aviation Administration predicts that traffic levels will continue increasing over the foreseeable future. It is important to identify and reduce the factors that increase ATC complexity because of the potential consequences of errors. This research examined the application of specific information coding techniques to ATC displays as a method of reducing complexity in the en route environment. It tested color coding of (a) aircraft...