Vehicle‐Borne Improvised Explosive Devices | Scope of Risk

Vehicle‐borne improvised explosive devices (VBIEDs) are an increasingly commonly used weapon by terrorists groups to target facilities, vehicles, or people. Vehicles may be loaded with explosives and driven by suicide bombers to the point of detonation, or may be remotely triggered. In some instances vehicles may also be driven by innocent drivers who have been coerced to drive the vehicle to the point of detonation. Vehicles can range from bicycles to large tankers. Secondary hazards might originate from fuels carried within vehicles, or chemicals that form a crude chemical delivery threat. Explosives come in a variety of forms, from mortar shells to plastic explosives. Additional components such as ball bearings may be packed around explosive materials to create additional damage. Explosives may also be disguised within door frames or other structural components of a vehicle. A VBIED poses an additional element of risk compared to an IED in that it is mobile and often delivered by a suicidal fanatic.

A detonated VBIED causes a range of threats to personnel and facilities, originating from the initial explosion. An explosion is a sudden release of energy caused by a rapid chemical reaction, which usually turns a solid into heat and gas. The rapidly expanding hot gas created by the reaction pushes the surrounding air out in front of it, thus creating a pressure wave, known as the blast wave. The effects of an explosion will depend on the power, quality, and quantity of the explosive material used. There are six basic effects that result from an explosion:

1.  Fireball.: The ball of fire created as part of the explosive process is very local to the seat of the explosion and is short‐lived; however, it can cause injuries and fires.

2.  Shattering.: This effect is local to the seat of the explosion, is normally associated with high explosives, and damages local structures and objects.

3.  Primary Fragments.: These are the fragments of the device and the packaging that are in close contact with the explosive charge. They are propelled at high velocity over a great distance. The primary fragments cause casualties and damage at a greater distance than the secondary fragments.

4.  Blast Wave.: This is the very fast‐moving high‐pressure wave created by the rapidly expanding gas of the explosion. It can bounce off hard surfaces and can be channeled down corridors and elevator shafts.

5.  Ground Shock.: Ground shock is produced by the effect of the explosion impacting the ground local to the seat of the explosion, sometimes creating a crater. The shock wave can damage pipes, cables, and other structures.

6.  Secondary Fragments.: These are the fragments that have been created by the blast wave imparting pressure on material unable to withstand the extreme pressure. The material that forms secondary fragments includes glass, roof slates, timber, and metal frames. These fragments can cause significant injuries and damage to the surrounding area.

Security standard operating procedures and security plans will be used to mitigate the probability of a VBIED occurrence. This may come in the form of physical security structures, policies, and security personnel. The IMP typically deals with the immediate measures taken following a detonation, or supports such measures if a suspect vehicle has been identified prior to detonation.