UFC 4-022-01
25 May 2005
6-2.3
Layout Guidelines for the Response Zone
Design the response zone with a sufficient length to provide adequate reaction time for
security personnel to respond to a threat. Provide final denial barriers at the termination
of the ECF to provide the capability to stop threat vehicles from using high-speed
attacks to gain entry to the installation. The necessary length of the response zone and
location of the final denial barriers is based on the provision of adequate response time.
6-2.3.1 Determining Length of Response Zone
Response time is the time required for complete activation of the final denial barriers
once a threat is detected. This implies the distance required to provide an adequate
response time is measured from a starting position where it can be assumed detection,
i.e. assessment of the threat, has already occurred. The length of the response zone is
calculated based on the velocity of the threat vehicle when it is detected, the
subsequent rate of acceleration, and the response time. The location of the threat
vehicle when first detected is based on the threat scenario and site plan. The rate of
acceleration is dependent on the type of vehicle. Generally, the acceleration
capabilities of threat vehicles are known.
The length of the response zone can be minimized, or the available response time
increased, by using passive barriers or roadway layout to control the velocity of vehicles
as they travel the Approach and Response Zones. It is recommended that roadway
layout features such as reverse curves (S-curves) be used to reduce the maximum
velocity of traffic. UFC 4-022-02 provides guidance on determining the maximum
attainable velocity including curved paths.
6-2.3.1.1 Threat Scenarios.
Consider all scenarios when designing the Response Zone, determine which scenario
governs, and verify the adequacy of the response time and final denial barrier selected.
As a minimum, consider the following three threat scenarios.
High-speed attack - A vehicle approaches the ECF at a moderate or high rate
of speed. The attack can initiate outside of the ECF or at any point within the
Approach Zone. The vehicle will be detected early due to the high-speed
approach; but the high speed and subsequent acceleration may not allow
security personnel enough response time to activate the final denial barrier.
The appearance of legitimacy until the Access Control Zone - A potential threat
vehicle approaches the ECF to attempt covert entry. The vehicle will approach
at a slow speed or stop to offer false credentials or a suspect vehicle attempts
to circumvent security from inspection or rejection lane. A suspect vehicle that
is rejected or directed to proceed to the inspection area, may initially indicate
compliance, however, once away from the guard attempt to enter the
installation. In this case, the threat is not detected until the vehicle proceeds
past the rejection lane or past the inspection area. In this scenario, the vehicle
is closer to the final denial barrier when detection occurs, but the vehicle is
moving at a low velocity and must then accelerate towards the barrier.
6-6
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