Calculations are done slightly differently, as this can depend on how many wheels, what size tyre and a number of other factors.
One of the main tests is how much weight can be applied to an un-filled square metre before it collapses, which is 420 tonnes in this case.
The maximum axle weight of 30 tonnes is a more practical indicator, as this shows that British Recycled Plastic grids are suitable for any UK road-legal vehicle, assuming the sub-base has appropriately installed for the type of traffic expected.