Dedicated Run
A run that typically always goes to the same place, on nearly the same
schedule. Many drivers would love to get a dedicated run. As a result, you
usually have to wait awhile before it's offered/available to you.
Dead-Heading
Operating a truck without cargo.
Demountable Rim
Multi-piece steel wheel rim assembly which is bolted to a spoke hub.
Demountable rims are still in use, though they have been replaced in many
applications by the simpler disc wheel.
Disc Wheel
Single piece rim/wheel assembly of stamped and welded steel or forged aluminum,
anchored by 8 or 10 nuts to a hub. A "Budd wheel" is a ten-hole, stud piloted
disc wheel; a design originated by the Budd Corporation.
Displacement
(Piston Displacement) Sum of the volumes swept by an engine's pistons as
they travel up and down in their cylinders. Based upon bore (diameter of
cylinder) and stroke (distance traveled by piston). Expressed in liters or
cubic inches.
Doubles (Twins,
Twin Trailers) Combination of a tractor and two semi trailers connected
in tandem by a converter dolly.
Driveline
All the components which together transmit power from the transmission to the
drive axle(s). These consist of at least one drive shaft (propeller shaft)
with a universal joint at each end.
Drive train
(Powertrain)
All the components, excluding engine, which transmit the engine's power
to the rear wheels: clutch, transmission, driveline and drive axle(s)
DRL (Daytime
Running Lights) System that automatically turns on a vehicle's low beam
headlights when the parking brake is released and the ignition is on...
Drop & Hook
This means that you take your empty trailer into a shipper's facility and drop
it. You then pick up a trailer that has already been loaded. It saves an
enormous amount of time and most drivers find a company that has a high
percentage of drop & hook to be a big advantage. (less dock time.)
