The movement of large or heavy loads is known as 'abnormal loads.'
Before a haulier can move loads which are classed as 'abnormal' (for example those with a gross weight exceeding 40 tonnes), he must notify and gain consent from the Police. In addition, if the gross weight or axle weights exceed those specified on the C and U regulations he must indemnify the Council as Highway Authority and all bridge owners along the proposed route (e.g. Network Rail).
An abnormal load can potentially go on any road provided the haulier complies with the law. Some roads are more suitable and more extensively used e.g. A Class Roads.
The law requires the haulier to give a minimum of two clear days notice to the Police, the Highway Authority (Council) and Bridge owners before moving the load.
The notice period for loads over 150 tonnes, 6.1 metres wide or 27.4 metres long is different and hauliers moving such loads need special orders from the Department of Transport.