Derogation

1) Term used in EU legislation to mean exemption (eg from specific provisions of a regulation). In effect, taking away the need for a country/transport operation to observe particular aspects of the law (eg the UK has a derogation – temporarily – from the EU 40-tonne maximum vehicle weight requirement).

DERA

1) Defence Evaluation and Research Agency. Tests and evaluates military and civil hardware (ie every piece of equipment used by the British armed forces, including of course the full range of logistics vehicles).

Depreciation

1) The practice of reducing the book value of an asset (eg a vehicle) over a period of time to indicate wear and tear and possible obsolescence.

Dependent demand

1) A classification used in inventory control where the demand for one item has a direct mathematical relationship with the demand for another higher level or parent component and where the demand for that item is ultimately dependent on the demand for the higher level or parent item. (Source: ILT Supply-Chain Inventory Management SIG)

Demurrage

1) Term meaning payment (due or charged) when load is delayed/held-up/not loaded/off-loaded, etc when agreed. Also applies if vehicle/ship/rail wagon delayed when empty. Most frequently found in shipping/rail transport.

Demountable body

1) Goods vehicle load-carrying body which can be detached from the chassis (to stand independently for loading/transfer, etc). Interchangeable (ie swap body) bodies/body types to give speed of vehicle turn-round and greater flexibility in operation.