Glossary of terms used on this site

These are the general terms for the trucking industry.

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Term Definition
A Trains

A trains are two trailers behind a tractor. The two trailers are connected together with a dolly converter. This configuration is undesirable owing to the additional pivot point created by the dolly converter.

Bill of Lading

The bill of lading is a legal document that allows the trucking company to transport the freight from point 'A' to point 'B'.

When the driver delivers the freight, she/he must get the receiver to sign the bill of lading. The signed bill of lading allows the trucking company to bill the consignee for their services.


In legal terms, the consignee is the person or corporation who is financially responsible (the buyer) for the receipt of a shipment. Generally, but not always, the consignee is the same as the receiver.

Day cab

day cab tractorThis truck is used to pull semi-trailers. The units are used for distances of less than 100 miles radius from the home terminal. These units are usually used for P&D (pickup & drop) and city work. Sometimes these shorter units are used to pull longer trailers (60'), which allows the unit to say within the overall legal length of 75' or 23 metres.


Driving empty to another location to pick up a load, or returning home.

Dolly Converter

It is an axle with a 5th wheel assembly and a hitch.  The hitch is usually a pintle hitch. The dolly converter is used to hook two semi-trailers together.


Is anything that aids in securing the load to the truck or trailer. Material such as pieces of wood, matting, shrink wrap, or similar material used to keep a cargo in position while being transported.

LTL (Less-than-load)

Less-than-load, or LTL freight, is part loads.\

Several freight shipments make up one load. Many tucking companies specialize in putting together full trailers from smaller shipments.


The different paths that the front and rear wheels take when cornering. The rear or trailer wheels will take a shorter path around the curve, corner or turn. Thus the driver has to compensate for this shortcoming by taking the curve, corner or turn wider.


Off-tracking is when the rear tires follow a different, shorter path than the front tires. The longer the vehicle the more off-tracking for which a driver must compensate.


53' foot trailers are the maximum length allowed without an oversize permit. In metric these are 16.2m; however, the industry measures trailers in feet.

48ft (14.6m) was the previous standard, and there are still many of these trailers in use.

Sleeper Birth

This is a semi-truck that has a sleeper birth unit attached to the cab of the unit. The driver has a access to the sleeping compartment directly from the cab of the unit. Inside the sleeper birth is a bed and living quarters for long haul drivers operating "over-the-road".

Sleeper Birth

sleeper berth unitSleeper birth trucks have a sleeper birth unit directly attached to the cab of the truck. These types of units are used to transport freight & services usually beyond 100 miles (160km) of the home terminal. For over-the-road truck drivers, these sleeper birth units are equipped with living quarters as well as a bed. Living quarters can include such things as a refrigerator, television and inverter which will give the driver access to plug in microwave ovens, computers and other electric devices.

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