The need to integrate human operators into the traffic management system dictates that the principles of user-centered design and human factors engineering must be incorporated into the overall system design and system engineering process. Some of the questions concerning systems for data collection and information promulgation are discussed in this article. A TMC operator in such a system may have access to dozens, or even hundreds, of remote cameras. If the design of the cameras affects the cameras effectiveness and ease of use, the design will consequently affect the effectiveness of the entire traffic management system. Some implementations require the operator to type in an identifier string on a keyboard or keypad while others allow selection of a camera icon off a map using a finger touch, mouse, or other pointing device.
Many implementations use a dedicated joystick or button-box.
Presets are arranged in a sequence and the operator s control actions cause the camera to progress through the sequence of preset views. In the joystick interface, left and right movements of the joystick result in left or right pans of the camera view. Backward and forward movements of the joystick result in downward and upward tilts of the camera. Zooming is accomplished by simultaneously pressing a button on top of the joystick and moving the stick forward or backward. Cameras are selected for viewing by typing an identifier string using the numerical keypad of the computer keyboard.