Dangerous Goods (DG): Materials classified as hazardous for transport, requiring special handling and adherence to regulatory guidelines.

Daycab: A type of truck without a sleeping compartment, typically used for shorter trips.

Deadhead: The distance a truck travels without any cargo, typically occurring between delivery of one load and pick-up of another.

Deck Height: The distance from the ground to the deck of the trailer, important for ensuring cargo clearance.

Decking: Creating a second level within a trailer to maximize space and transport more goods. Often used in moving and furniture transport.

Dedicated Lane: Regular, consistent loads often under a contract, where the driver transports cargo on the same route repeatedly.

Dedicated Truck/Load: A scenario where an entire trailer is reserved for a particular load, even if the cargo doesn't fill the entire space.

Demurrage: Charges incurred when a shipment is left at a terminal beyond the allotted free time, typically occurring in port operations.

Detention: The time a driver spends waiting at a loading dock or other location beyond the scheduled time, often leading to extra charges.

Detention Slip: A document confirming the time a driver was detained at a loading or unloading site, used for billing and record-keeping purposes.

Differential Lock (Diff Lock): A feature on some trucks that locks the differential to provide equal power to both wheels, enhancing traction in difficult driving conditions.

Dimensions (Dims): The measurements of cargo, crucial for planning space utilization and compliance with transportation regulations.

Dispatcher: An individual responsible for coordinating and managing the transportation of goods, including route planning and communication with drivers.

Dozer: A bulldozer, which is a heavy machine often transported by truck for construction or land clearing operations.

Double Brokered: A situation where a freight broker re-sells a load to another broker, often leading to complications in logistics and payment.

DOT (Department of Transportation): The government department responsible for transportation regulation and oversight.

DOT Inspection: Regularly required checks by the Department of Transportation to ensure vehicles meet safety standards and regulations.

Drayage: Transporting goods over a short distance, often as part of a longer journey, such as moving cargo from a port to a nearby warehouse.

Driver: The individual operating the truck, responsible for transporting cargo from one location to another.

Driver Assist: When the driver provides help in loading or unloading the cargo, often requiring additional payment or arrangement.

Drop and Hook: A process where a driver drops off a loaded trailer at a customer site and hooks up to another trailer without waiting for loading or unloading.

Drop Trailer: A practice where a trailer is left at a location for a period, typically for loading or unloading, without the truck.

Dry Bulk: Cargo in the form of powder, granules, or other granular materials transported in bulk, such as cement or grains.

Dry Van: A standard enclosed trailer used for transporting general cargo that does not require temperature control.

Dunnage: Materials like wood blocks used to secure cargo during transport to prevent movement or damage.

Dunnage Bag: An air-filled bag used to secure and stabilize cargo in a trailer to prevent damage during transit.