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Unladen weight

The unladen weight of any vehicle is the vehicles own weight when not carrying any goods or burden. This is:

Maximum authorised mass

The term maximum authorised mass (MAM), which is also known as gross weight and permissible maximum weight, is the maximum weight of the vehicle that may be used on the road including the maximum load the vehicle may safely carry. This is normally shown on a plate fitted to the vehicle.

If a vehicle is unlikely to be used at its potential maximum weight most vehicles may be downplated, i.e. the vehicles springs or other components can be changed, so that only a lighter load can be carried. The maximum authorised mass or gross weight is a factor in determining what driving entitlement is required. 

Plated weight

The maximum authorised mass should be shown on the departments manufacturing plate fitted to the vehicle. This means the marking on a goods vehicle, by means of a ministry plate, showing the maximum weights for that particular vehicle eg maximum authorised mass, and in certain cases, train weight.

Train weight

Train weight is the combined MAM of the vehicle and the trailer it is pulling.

Further information

All enquiries concerning maximum weights of rigid vehicles, trailers and articulated combinations (but not driving licence categories) should be referred to:

Transport, Technology and Standards
Department for Transport
Zone 2/01, Great Minster House
76 Marsham Street
London
SW1P 4DR

Email:

• tts.enquiries@dft.gsi.gov.uk Opens new window