Liabilities. Possible legal issues resulting from accidents (i.e., deaths, injuries) and legal
jurisdiction (i.e., state, local, foreign country) should be considered when deciding to install an
active vehicle barrier system.
Actions to Avoid
a) Do not install barriers that must be installed below ground level in locations where
there is a high water table. Unless the excavation can be drained, water collection will cause
corrosion, and freezing weather may incapacitate the system.
b) Do not install barriers at entrance and exit gates without also installing passive
barrier systems along the remaining accessible perimeter of the protected area.
c) Avoid extensive protection of a large facility perimeter. Protection of individual
buildings or zones within the perimeter is generally more cost-effective.
d) Avoid installing barriers where they are not under continuous observation. Most
types of barriers can be easily sabotaged.
e) Avoid locating barriers immediately adjacent to guard posts to minimize possibility
f) Do not neglect to install barriers on the exit side, as well as the entrance.
g) Avoid long, straight paths to a crash-resistant barrier. Where this cannot be avoided,
provide a passive-type barrier maze to slow the vehicle.
Barrier Capability. In general, vehicle-crash-resistant barriers should be used at vehicle
access points to sensitive areas and enclaves. Active and passive barriers should be tested against
specific threats (vehicle weight and speed) or analyzed using finite element analysis or computer
programs, specifically developed to analyze performance of vehicle barriers (see applicable
document PDC TR90-2). Supplemental gate and fencing reinforcements may also be needed to
provide consistent security.
The acceptable penetration distance will vary among installations, depending upon the
locations of the barriers relative to the resources to be protected. The appropriate penetration
distance for a given facility should be determined by the results of a threat and risk assessment and a
physical security survey. To illustrate, refer to Example 1, Appendix B.
The Delta TT207 vehicle barrier selected as a candidate barrier must be capable of
stopping the vehicle and allowing little or no penetration. In the example, sufficient standoff
distance is not available to protect Building 827 from the expected explosive-loading conditions.
Possible options would include moving the barriers further away from the target, closing the