An area confining a crowd can be a building, a sports arena, an underground sub-station. Safeguarding crowd security in over-populated places (airports, metro stations, stadiums, etc.) in hours of high concentration of people (rush-hours or during large-scale events like music concerts or major sport events) is probably on the top of the list of public safety issues. Until now, there has been significant progress in terms of secure design of buildings and places hosting large crowds with respect to safe access, use and evacuation. This secure design translates to the prediction for emergency exits, fire protection systems, evacuation plans, time needed to take actions etc. However, such approaches are static in the sense that they do not exploit the crowd dynamics that emerge during evacuation, the effect of the responders’ evacuation actions as well as crowd psychology. The latter is particularly evident in case of an emergency or within a critical situation, the sense of confinement creates a state of mental discomfort for the crowd. In addition, physical pressure built due to difficulty in occupying a place or free movement, creates a state of physical impatience. In combination, both these states may lead some of the crowd members to panic, or create an overload of the available capacity of stair or gates, thus probably creating a more dangerous situation within an emergency situation (hysteria).
Under such circumstances, one needs to form a complete view of the situation compose a command chain which consists of human resources (command hierarchy) and technical resources (sensors, communication and prediction tools) and as a result direct the crowd (control) towards safe exit(s) as fast and as calmly as possible. This process is generally termed as evacuation which can be defined as the escape from an area due to a real or a potential threat.