Which type of barriers include drop arm, hydraulic rams, and metal crash gates?

The category that includes drop arms, hydraulic rams, and metal crash gates is known as active barriers. Active barriers are designed to control access dynamically, meaning they can be operated and adjusted to respond to real-time security needs. They are typically movable and can be activated or deactivated based on specific security protocols or situations, providing an immediate response to potential threats or changes in the environment.

In contrast, passive barriers are fixed installations that provide protection without the need for movement or activation, such as walls or fences. Security barriers could encompass a broader category that includes both passive and active systems, and perimeter barriers specifically refer to structures that delineate the boundaries of a secured area. Active barriers, therefore, stand out because of their functionality and adaptability in reacting to security situations.