Vehicle Barrier Design
At the conclusion of a vulnerability study, the organization should solicit various manufacturers to identify the most appropriate style of anti-ram vehicle barrier. Organizations have two primary choices of vehicle barriers: passive, such as bollards and planters, and active, such as power gating and fencing systems and electric retractable bollards.
Appearance: First and foremost, aesthetics must be considered in design. Targets in urban areas will likely require a fairly discrete perimeter protection device, such as bollards, planters, and berms, which blends into the environment. On the other hand, targets in urban warfare areas may require barriers that express the gravity of the threat an organization faces, such as concrete jersey barriers and anti-ram walls.
Installation: Today, many manufacturers offer protective barrier system with shallow installation capability. Many underground infrastructures especially in urban areas make deep excavation impractical. For this reason, a vehicle barrier that can be shallowly installed should be considered. Installation of shallow-mounted barriers may also allow faster and cheaper replacement of a vehicle barrier if necessary.
Barrier Dimension: The width of the barrier must be considered as well. Many manufacturers produce vehicle barriers of different length to accommodate entry points. The dimensions should accommodate an oversized vehicle—such as an oversized fire truck, even at a wide radius turn.
Power Requirements: For organizations that choose power anti-ram barriers, power requirements must also factor into their decision. The power supply should provide continuous and uninterrupted power with a back up source at all times. Some manufacturers offer battery back-up standard or as an upgrade to provide continuous operation of a barrier during an unscheduled power failure for a limited number of cycles.
Safety: The presence of a vehicle barrier must be clearly defined for drivers and pedestrians. The barrier not only defines the boundaries of a protected area, but should serve to minimize accidental entry by unauthorized persons. Signage warning of the vehicle barrier must be in simple to understand language. Many vehicle barrier manufacturers provide decals to warn oncoming traffic when they are in a fully secured area.
Another safety option that organizations should consider is an illuminated gate arm with light emitting diodes when they choose certain powered anti-ram barriers. The gate arm should hover directly over the barrier to show its clear position. The gate arm should be installed in front of the barrier on the traffic side of the barrier and provide a common warning command to oncoming traffic, such as “STOP.” Depending on aesthetics limitations, manufacturers may offer options to paint the surface of the barrier in bright colors to create a sharp contrast to the roadway.
For checkpoints in close proximity to pedestrian walk ways, an audible alarm, capable of providing a continuous audible tone, can be used to alert pedestrians of the barrier when it’s in use. Nevertheless, every effort should be made to direct pedestrian walkways away from the barrier if possible.
No matter what other warning devices are used, every measure must be taken to ensure that motorists are aware of an approaching vehicle barrier to prevent an accidental collision. Many vehicle barrier systems are equipped with safety loops, which are designed to prevent the unintended deployment of a barrier when a vehicle is present over the designated field on both the attack and the secured side of the barrier. The manufacturer should provide standards on the size and location for installation of these loops. The safety loop should be capable of being overridden by security staff.