Large or heavy loads, for example those with a gross weight exceeding 40 tonnes, are known as abnormal loads.

An abnormal load can potentially be transported on any road, provided the haulier complies with the law and notifies the authorities.

Some roads are more suitable and more extensively used for transporting abnormal loads, such as A-class roads.

If a haulier wishes to move a load that is classed as abnormal, they must comply with the law by notifying and gaining consent from the police.

If the gross weight or axle weights exceed those specified on the construction and use regulations, the haulier must also indemnify the highways authority (in most cases the Council) and all bridge owners along the proposed route (for example, Network Rail).

Notice periods

The law requires the haulier to give a minimum of two clear days notice to the police, the Highways authority and bridge owners before moving the abnormal load.

The notice period is different for loads over 150 tonnes, 6.1 metres wide or 27.4 metres long and hauliers need special orders from the Department for Transport to move loads of this size.