The proliferation of motor vehicles over the past 50 years has enabled terrorists and criminals to use vehicles as a means of damaging military and civil sites and departing from the scenes of crimes. A method of stopping such vehicles to apprehend the occupants was needed.
A statement of requirement for vehicle-arresting equipment was evolved, identifying the need for portable vehicle-stopping equipment to capture vehicles and their occupants, to be used by military foot patrols and police forces. Within this requirement was the provision that arresting equipment would injure occupants. At the same time, the need also emerged for equipment to prevent unauthorised vehicles from seeking to gain entry into military and civil sites. Such vehicle entrapment systems needed to be capable of preventing a vehicle weighing 30 tonnes or less that may be moving at speeds up to 60-70kph on impact with a barrier, from reaching its target.
| Lazy tongs portable road barrier |
A man-portable equipment was evolved and designed around the concept of an expanding and contracting lattice arrangement that was small enough to be contained in a carrying box and could present a series of tyre-destructive elements to an oncoming vehicle. A hollow spike with sharp edges was developed to penetrate tyres. In addition, a means to hold the spike so that it would detach and enter tyres was evolved. On entry into a tyre, air-release slots in the spike caused deflation. An operational device was trialled and proved effective in stopping vehicles up to Land Rover size.
The design is based on the concept of an expanding and contracting lattice onto which 170 spikes are pinch-fitted into cups. The unit can be deployed from a launch/carrying box by two men in 15 seconds, with ropes to secure the lattice at each end. The no-miss configuration of the lattice ensures that a vehicle running over the barrier has its tyres impaled by the spikes. Consolidation into a tyre is effected by the successive revolutions of the vehicle wheel. When the spike reaches the air under pressure in the tyre, it is released to the atmosphere through the hollow section of the spike, deflating the tyres in a controlled manner. This ensures that occupants are unharmed and available for apprehension. A single-arm version provides greater control over a wide road area that means it is suited for use at border control and military check points.
| Single-arm lazy tongs portable road barrier |
A series of vehicle entrapment and road-blocking equipment is available commercially to suit a variety of applications. Contained underground in a strong steel box-like construction, the equipment comprises tyre-destructive elements mounted on rotating shafts. The elements remain under the road surface until activated, when they protrude through a slotted grille mounted on the road surface. Such installations are operated hydraulically. The tyre-destructive elements consist of hardened steel blades that are capable of stopping a vehicle of up to 30 tonnes travelling at speeds below 60-70kph on impact with a barrier. These elements will destroy vehicle tyres to rim level, as well as the steering gear and lower engine section and bring the vehicle to an abrupt stop. Baleen-type vehicle entrapment installations have the added facility of an adjustable inclination angle of the blades, that can be selected according to the vehicle threat. Additionally, a section of the blade detaches and completes vehicle destruction past the barrier, ensuring that the installation is not damaged.
| Deployment of lazy tongs portable road barrier |
The rising-spike vehicle entrapment system is incorporated in the road matrix. Underground sections of one-metre lengths can be joined together to form a barrier of any desired length. A steel grille lies on the road surface, into which slots are cut to allow the rise and fall of detachable tyre destructors. Such tyre destructors are designed to become detached from their revolving shaft housings to impale the tyres of a vehicle. Rapid deflation in a controlled manner is obtained through the centre hollow section of the deflator, causing the vehicle to come to a standstill at a prearranged distance past the barrier with the occupants unharmed and the barrier intact, ready for the next intruder. Single and double rows of tyre deflators of this type are available.
Road blockers are designed to rise above the surface of a road and physically prevent the passage of vehicles. They rise and fall from an underground installation, usually by hydraulic means. In their simplest form, heavy-duty bollards are linked together to rise above the road and prevent passage to a vehicle. A more sophisticated form is purpose-built to span a section of road. This device rises up to one metre above the road surface and physically prevents access to any vehicle. Its sheer bulk and appearance acts as a visual deterrent to would-be intruders.
| Scatterjack airborne vehicle-arresting equipment |
Scatterjacks are tyre-destructive elements mounted within a spherical container. They are dispersed from an aircraft via a carrier pod over a designated target. When in free flight, an aerofoil controls the descent trajectory and speed. On contact with the ground, the scatter-jack bounces into the air, during which time it becomes armed. This type of vehicle-arresting device is used principally in areas of heavy vehicle concentration on battlefields.
Future development in underground vehicle barriers will include delayed-action destructive elements. These are designed to complete vehicle under-section destruction at a defined distance past the barrier, causing the vehicle to come to a standstill in a predetermined area. This prevents damage to the barrier on impact and ensures it remains operational for use against subsequent attacks.
Future development in the area of portable road barriers will centre on providing greater stability to the lattice array during successive attacks by a number of vehicles. This will be achieved by using the weight of the vehicle to fix road impingers on the underside of the lattice into the road surface, preventing lattice migration after contact with the vehicle.
