Pretty simple in Australia, there are National Standards in regard to load restraint. All loads must be contained as in a dump truck or restrained. Restraint means held so no upward movement (bumps), sideways movement (cornering, wind and slopes), forward movement (braking and slopes), or rearward movement (wind, slopes and acceleration).
The amount of restraint required is expressed as "G" or gravity, 1G=weight of load.
The figures are also expressed as a % of the weight of load and are:
20% upward, 50% sideways, 80% forward and 50% rearward.
The restraint has to also prevent the load moving, e.g. pipe must be belly wrapped so it cannot move on a flatbed.
Restraint equipment is rated by the manufacturer or given a nominal rating according to size. Straps, and load chains are usually stamped or tagged with the rating. Ropes for instance are rated according to diameter.
Overhang to the front, side, and rearward is also regulated. Overhang cannot exceed 1.2 metres (4 feet) beyond either the vehicle or the last point of support whichever is the lesser.
In addition rearward overhang cannot exceed 60% of the vehicle's wheelbase.
What is more the regulators have legislated to implement "Chain of Responsibility".
For example if a transport company loads a vehicle that is over or otherwise unsafely loaded, the driver is responsible so too are the loader, supervisor, manager and all the way to company directors.
Makes companies introduce measures to make sure unsafe loads do not go out on the road.
so, if for example I allow a load of hay, collected by a customer leave my premises unrestrained and an accident happens , i can be prosecuted and face the same penalty as the driver of the vehicle that dropped the load.
Can tell you all loads are secured before they leave.
Some do not learn, December last year a road train (2 semi trailers) on one prime mover loaded 2 bales wide and 4 high started to lose a load a mile from my home. Went with a big front end loader and pushed it up and on again. Idiot had only one 2.5 tonne 2 inch strap holding on each row of eight bales and 2 straps holding the last row on the second trailer. The two last rows were leaning out at nearly 45 degrees. Confirmed idiot did not have even one spare strap to secure the righted rows.
The prime mover and trailers were grossing about 135.000 lbs. This good samaritan then lent the driver 2 brand new straps to secure the wayward load. Did not get them back for 2 months and very second hand.
Have to now ask: Who the idiot was?