UFC 4-022-01
25 May 2005
or during an actual response to a threat. Where possible, incorporate an appropriate
delay time (minimum of 4 seconds) into the barrier control sequence to allow
sequencing of traffic signals and lights at the final denial barrier to allow vehicles
approaching the barrier to either clear it or stop safely in front of it before it deploys.
Automatic detection loops embedded in the pavement around the active vehicle barrier
system can be used to avoid deployment of the vehicle barrier when an authorized
vehicle is within the loop detection zone and the barrier is activated.
During emergency barrier activation, a barrier would not initially activate if the detection
loop indicates the presence of a vehicle. In order to avoid tailgating to defeat the
barriers, it may be necessary to activate the barrier as soon as that first vehicle clears
the loop, regardless of whether a second vehicle enters the presence loop. It may also
be necessary to activate the barriers once the maximum allowable delay time has been
reached even if the detection loop indicates a vehicle is in the presence zone. Place
warning lights at all active vehicle barriers. When the active vehicle barrier is in the
closed position (stopping vehicle flow), a red stoplight should be used. At all other times
a yellow flashing light should be used (Securing U.S. Army Site Access Points.)
Consider other safety measures that provide protection for innocent motorists from
barrier activation such as non-lethal active vehicle barrier systems that reduce the risk
of injury and level of damage, requiring vehicles to stop prior to the active vehicle
barriers in conjunction with providing vehicle detection loops and controls and providing
additional channelization in front of each barrier, or utilizing speed management
techniques to control the velocity of traffic. Further information on traffic safety
considerations related to active vehicle barriers including the use of traffic signals and
sequencing can be found in Traffic and Safety Engineering for Better Entry control
Facilities.
Active vehicle barrier systems can require significant maintenance. To facilitate
maintenance and reduce costs it is desirable that the types of vehicle barriers be
minimized at each installation or within a region.
6-3.3
Controls for Active Vehicle Barriers
Locate the main, multi-function control panel for the active vehicle barrier systems in the
gatehouse. The control panel should require a key for normal operation and control all
lanes. Provide a separate emergency control on the panel to initiate the emergency fast
operation (EFO) mode of the final denial barriers in all entrance and exit lanes. A
tamperproof, emergency activation control for the final denial barriers should be located,
as a minimum, at each guard facility or post (channelization island, gatehouse,
sentry/guard booth, and overwatch position). The emergency activation control will
trigger the accelerated deployment function of the barrier system. Providing redundant
control will reduce reaction time and increase the effectiveness of response. All
activation controls, including individual emergency activation controls, should be
protected from inadvertent use by a shield or cover.
The active vehicle barrier control system should be designed such that
deactivation of the final denial barriers, after an emergency activation is triggered at the
master panel or other locations, requires a key or similar device. This prevents a
6-11
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