ISO 22915 deals with the safety of industrial trucks, as defined in ISO 5053, relative to their stability and the verification of that stability. For the purposes of ISO 22915, industrial trucks are wheeled, self‑propelled or pedestrian‑propelled vehicles, excepting those running on rails. They are either operator‑controlled or driverless and designed to carry, tow, push, lift, stack or tier in racks. ISO 22915-20:2008 specifies an additional test for verifying the stability of a laden truck specifies an additional test for verifying the stability of a laden truck whose utilization creates the special operating condition whereby the load centre of gravity is substantially offset from the truck's longitudinal centre plane. It is applicable to the following types of truck: It is applicable to the following types of truck: counterbalanced trucks; reach (retractable mast or forks) and straddle trucks; pallet stackers; bi‑directional and multi‑directional (retractable mast or forks) trucks; rough-terrain variable reach trucks; counterbalanced trucks fitted with articulated steering; variable reach trucks; rough terrain trucks with mast. A load is considered to be substantially offset if displaced by more than 100 mm, for a truck with a rated capacity less than 5 000 kg, 150 mm, for a truck with a rated capacity greater than or equal to 5 000 kg and less than or equal to 10 000 kg, 250 mm, for a truck with a rated capacity greater than 10 000 kg and less than 20 000 kg, 350 mm, for a truck with a rated capacity greater than or equal to 20 000 kg.