This pattern displays visual notifications or plays back audible notifications for the user.
Operators need to distribute attention to important events in stressful situations.
With several events going on in several locations of the system, the user must be able to monitor these events based on perceptual clues and direct his attention to the event with the highest priority. These clues are, based on sensual capabilities, visual or audible.
The design of the application needs to be such that the operator is not unnecessarily distracted or disrupted by applications events and notifications. These need to be designed to support the operator’s mental model of the current situation in the control room.
A model to support the mental model of the control centre task must be defined. Such a model must address issues of visualisation and audio design, system feedback, mapping the real world to the system, and consistency. Directing the operator’s attention while not trying to disrupt the work by unnecessary distraction should be the main concern during design.
Central and peripheral area of attention. Operators in railway control centres typically have a main area they control, which is also mapped to one or more screens. These screens are used most frequently used and, therefore, should be placed in a position in front of the operators such that it is possible to watch these screens without being forced into an unnatural posture, which may result in strain injury. Systems of lower priority should be placed in the peripheral area of vision and bring themselves to attention using animated visual clues or subtle audible clues.
Automation. Signallers repeatedly stated that they tended to pay less attention if they only relied on automated routing systems. Therefore, special consideration must be given to the question whether tasks should be automated or not.
Design to help support an operator’s attention helps recognising possible safety-relevant situations in time, therefore, helps to prevent serious consequences.
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