Inadequately restrained cargo is a problem in a wide range of vehicles, from passenger cars to heavy trucks. In a crash, the force needed to restrain the cargo is many times the weight of the cargo itself. In a passenger vehicle this means that the barrier between the cargo and the occupants must be capable of preventing the cargo from entering the passenger compartment. In heavy trucks, cargo restraints are generally used to prevent the shifting of cargo that could affect the stability of the truck and to keep the cargo on, or in, the truck during normal driving maneuvers.
A somewhat unique problem occurs in the armored security vehicle. These vehicles are often used to transport very heavy, dense, valuable cargo. More specifically, this cargo is often coin and/or boxes containing paper currency. In many cases this cargo, which may exceed 2268 kilograms (5000 pounds), is carried in the same compartment as personnel. Without a restraint or barrier capable of withstanding the loads generated by this cargo, occupants are placed at risk of serious injury from this shifting payload, especially during crash events. In order to protect these occupants, the cargo restraint or barrier must be able to prevent the cargo from entering the occupant's space and not allow the components of the vehicle or the barrier itself from loading the occupant during foreseeable crash events.
The capability of one type of cargo restraint used in these vehicles was analyzed and tested in a 30 mph frontal barrier test and found to be inadequate to prevent cargo from moving into the occupant's space. Alternative cargo restraints and barriers were considered and analyzed. One design was selected and a prototype was fabricated and tested in a simulated frontal 30 mph crash on a horizontal accelerator (sled) with the same cargo as was used in the first test. This improved design remained in place and kept the cargo away from the occupant's space and thereby would have prevented any injury to the occupant from the cargo. This program demonstrates the type of cargo barrier needed to restrain dense cargos, such as coins, and protect personnel from injury due to shifting cargo. These concepts have application in all types of vehicles.