UFC 4-022-01
25 May 2005
6-2.3.1.2 Response Time
The response time includes the time for security personnel to react to a threat and
initiate the activation of the barrier system and the time for the selected barrier system
to fully deploy and close the roadway. The time for the barrier system to deploy will be
based on the operational characteristics of the final denial barrier selected; however, in
no case must the time be taken less than 2 seconds. The time for the barrier system to
deploy should include the time for sequencing traffic signals where they are employed
as a safety measure. The time for security personnel to react to a threat and initiate the
response is dependent on the standard operating procedures and location of
emergency operation controls. The time assumed for the reaction of personnel will be
determined based on the specific conditions and layout of the ECF, however, it should
not be taken to be less than 3 seconds. When evaluating the threat scenario
associated with vehicles traveling to or from the inspection area, the reaction time for
personnel may be reduced to 1 second if approved by the security personnel and if the
standard operating procedure includes personnel on standby at the barrier activation
controls when a suspect vehicle is traveling to the inspection area or being rejected.
The following examples illustrate the calculation of the required length of the response
zone.
Example 6-1:
Given:
High speed attack scenario - Vehicles enter the installation from a right or left hand turn
that limits the speed of incoming vehicles to a maximum of 20 mph (32 km/hr)
The approach zone is 250 ft (76.2 m) long, flat, and straight
Security personnel are provided automatic warning of speeding vehicles 100 ft (30.5 m)
prior to the checkpoint and the speed limit is 20 mph (32 km/hr) in the ECF. The over
speed detection is set at 35 mph (56 km/hr), with the first loop 100 ft (30.5m) from the
start of the approach zone and the second loop 50 ft (15.23 m) from the first.
A threat assessment indicates high performance vehicles (acceleration rate of 11.3
ft/sec2 (3.44 m/sec2)) could be used in an attack
The final denial barrier takes 3 seconds to fully deploy when the emergency fast
operation (EFO) is triggered. Based on the location of EFO controls, security personnel
may take as long as 4 seconds to trigger the final denial barrier once the threat is
detected.
Solution:
The initial velocity when the vehicle enters the approach zone is 20 mph (32 km/hr.) The
time the first detector is reached:
2
2
traveled. Therefore,
2
meter
meter
meter
km
miles
v f = 8.889
+ 2 ⋅ (3.44
) ⋅ ( 30.5m) = 17
= 61.2
= 38
sec 2
sec
sec
hr
hr
6-7
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