What is a critical aspect of active physical security measures?

Active physical security measures are designed to directly engage and deter potential threats in real-time. This characteristic is essential because such measures, which can include alarms, surveillance systems, and even security personnel, function by providing an immediate response to incidents or the presence of intruders. By actively deterring threats, these measures play a crucial role in preventing security breaches before they occur, enhancing overall safety and security.

The visibility of active measures, their maintenance requirements, and the necessity for power are important considerations but do not define their primary function. Visibility is relevant but not a prerequisite; some active measures can be discreet. Maintenance is also a factor, yet active systems often entail ongoing upkeep to ensure effectiveness. Moreover, many active systems depend on power sources, which is integral for their operation—such as surveillance cameras requiring electricity to function—making the absence of power not characteristic of most active measures.