| Glossary Word | | Glossary Description | | |
| Deadweight Tons (DWT) | | The cargo carrying capacity of a vessel, including fuel oil, stores and provisions. |
| |
| Demand Management | | Measures to restrict the amount of car use undertaken such as through greater control on the price and availability of public cassarking. |
| |
| DETR - Department of the Environment, Transport and the Regions | | Arm of Government which, amongst other things, is responsible for allocating Government funding on capital road schemes, setting standards of road design, signing, and so on. |
| |
| Diesel Particulate Filter (DPF) | | A diesel particulate filter (DPF) is similar to a diesel oxidation catalyst and is one of the two major technologies being employed to meet the 2007 emissions regulations. A DPF is considered a \"flow-through\' device whereby the exhaust is forced through a honeycomb shaped, ceramic filter that is blocked at one end. Because of this design, it is important to monitor the exhaust back pressure and ensure the DPF is cleaned properly so that the filter does not become blocked. Most filters are designed to clean themselves (referred to as passive regeneration) but this requires an elevated engine temperature to burn off the trapped PM. For vehicles that don\'t meet the minimum temperature requirements, the filter will trigger what\'s referred to as an \'active regeneration event\'. This means that some diesel fuel will be allowed to pass through the engine un-combusted and will be burnt over the catalyst, allowing the PM within the filter to be burned away. One major difference between the DOC and DPF is that the DPF requires the use of ultra low sulfur diesel (ULSD) fuel with sulfur content at or below 15 parts per million. Emission reductions are approximately 50 - 90% for PM, 90% for hydrocarbons and 90% for carbon monoxide. |
| |
| Direct Fired Heater (DFH) | | Direct fired heaters, or bunk heaters, are devices that can reduce idling by providing in-cabin heat for drivers in cold temperatures. Some product models offer an engine heating option that will also keep the engine warm overnight. Most DFH\'s operate by using fuel directly from the main tractor fuel tank. These devices can generally provide 10 to 20 hours of heat on a single gallon of diesel fuel, depending on the settings and options. Typical costs for this device range from $900 to $3000. |
| |
| Distribution Center (DC) | | Distribution centers store and sort goods using warehouse space so that full truckloads of merchandise can be sent to a single destination or to multiple destinations along a specific route. |
