Any load carried on a vehicle must be sufficiently restrained to prevent movement caused by the forces that arise from the vehicle passing over road undulations, when it changes direction or when it is being braked or accelerated (see figure 1 and figure 2).
The forces involved in restraining the load when braking depend on the deceleration and the weight of the load. Thus, as braking efficiencies and vehicle payloads increase, it becomes more important that load restraint should be adequate.
The forces involved in restraining a load under braking are not dependent on the speed of the vehicle. They may be the same at low speeds as at high speeds, in both forward and reverse directions. If, however, a load does move at high speed, it will have more energy and will cause more damage.
It requires much more force to stop a load that has started moving than it does to prevent the movement in the first place. It is essential that the vehicle is loaded and the load restrained in such a way that no part of the load can freely move in any direction relative to the vehicle.
The total restraint required to accommodate the forces that arise will generally be obtained from a combination of the following:
A load carried on a vehicle without restraining devices will not be secure because the frictional restraint between the load and the platform of the vehicle will be less than the dynamic forces that tend to move the load. It follows, therefore, that it is necessary to provide additional restraint to prevent the load moving.
Last updated: 22 July 2014