d. Antihelicopter/Antiair obstacles are placed on suitable landing fields
and parachute drop zones to demolish aircraft in landing and impede movement
and landing of paratroopers.
Effective obstacles include craters, posts,
stakes, barbed wire, immobilized or parked vehicles, rock-filled oil drums,
minefields, felled trees, and persistent toxic chemical agents used alone or
integrated with other obstacles.
e. Roadblocks are obstacles across a road which will cause a military
vehicle to stop, slow down, or detour around it.
Roadblocks normally are
sited to supplement a prepared or natural obstacle (Figure 2-23).
f. Demolition obstacles. Properly emplaced demolition charges can create
rock slides, road craters, and other hindrances to vehicular traffic.
Demolition charges are normally placed on bridges, road junctions, mountain
passes, and embankments. Comparative cover may reveal spoil marks for the
charges. Electronically controlled charges may have a cable trench leading
from the charge (Figure 2-23).
Figure 2-23. Roadblock Caused by Demolition Charge.