Trucker glossary

Trucking has its own language. Each term below gets a short, plain-English definition, with a link to the full guide where we have one.

71 terms

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14-hour rule

The hours-of-service limit that says property-carrying drivers may not drive beyond the 14th hour after coming on duty. See hours of service.

34-hour restart

Taking 34 or more consecutive hours off duty to reset the weekly 60 or 70-hour limit.

A

Accessorial

An extra charge on top of the linehaul rate, such as detention or a stop-off fee.

Air brakes

Brakes operated by compressed air, standard on heavy trucks. See air brakes.

Air ride

Suspension that uses air bags instead of only steel springs for a smoother ride.

Apportioned plates

Registration that lets a truck operate in multiple states, with fees shared under the IRP.

Axle weight

The weight carried by one axle or axle group, limited by law. See weight limits.

B

Backhaul

A load that brings a truck back toward its home base.

Bill of lading (BOL)

The shipping document that lists the freight, shipper and receiver.

Bobtail

A tractor driving without a trailer attached.

Bridge formula

The federal formula limiting weight based on axle count and spacing.

Broker

A company that arranges loads between shippers and carriers without owning trucks.

C

Cab-over

A truck with the cab sitting above the engine, with a flat front.

Cargo securement

Rules and equipment for tying down loads. See cargo securement.

CDL

Commercial driver's license. See CDL classes.

Chassis

The frame that carries an intermodal container. See intermodal containers.

Converter dolly

A unit with a fifth wheel used to connect a second trailer in doubles and triples.

CPM

Cents per mile, a common way of paying drivers. See life and pay models.

CSA

Compliance, Safety, Accountability, the FMCSA program that scores carrier safety.

D

Day cab

A tractor without a sleeper berth. See sleeper vs day cab.

Deadhead

Driving without a paying load.

DEF

Diesel exhaust fluid, a urea solution used to reduce emissions in modern diesels.

Detention

Time waiting at a shipper or receiver beyond the free period, often paid.

Dispatcher

The person who assigns loads and routes to drivers.

DOT number

A unique number the US Department of Transportation assigns to commercial carriers.

DPF

Diesel particulate filter, which traps soot from the exhaust.

Drop and hook

Dropping one trailer and picking up another, preloaded, to save time.

Dry van

An enclosed, non-refrigerated trailer. See dry van and reefer.

DVIR

Driver vehicle inspection report, the written record of defects found during inspections.

E

ELD

Electronic logging device, which records driving time. See ELDs.

Endorsement

An addition to a CDL that allows certain vehicles or cargo. See CDL endorsements.

F

Fifth wheel

The coupling plate on a tractor that connects to the trailer's kingpin.

Flatbed

An open trailer with no sides or roof. See flatbed and step deck.

FMCSA

Federal Motor Carrier Safety Administration, the US agency that regulates trucking safety.

Fuel surcharge

An extra payment that adjusts with fuel prices.

G

Gladhands

Couplers that connect the tractor's air lines to the trailer.

Gross vehicle weight (GVW)

The total weight of the vehicle and its load.

GVWR

Gross vehicle weight rating, the maximum weight a vehicle is designed to carry. See truck classes.

H

Hazmat

Hazardous materials, which require a special endorsement and placards.

Hours of service (HOS)

Federal rules limiting driving and on-duty time.

I

IFTA

International Fuel Tax Agreement, which shares fuel tax among states and provinces.

Intermodal

Freight that moves by more than one mode, such as rail and truck.

J

Jackknife

When the trailer swings around toward the cab, usually in a skid.

Jake brake

An engine brake that helps slow a diesel truck. See jake brakes.

K

Kingpin

The steel pin on the trailer that locks into the fifth wheel.

L

Landing gear

The legs that support the front of a trailer when it is not hooked up.

Linehaul

The base payment for moving a load from origin to destination.

Load board

An online marketplace for available freight. See freight and load boards.

Lowboy

A trailer with a very low deck for tall heavy equipment. See lowboy and RGN.

Lumper

A worker paid to load or unload freight at a warehouse.

M

MC number

Operating authority number for carriers that haul regulated freight for hire across state lines.

N

No-Zone

The blind spots around a large truck. See sharing the road.

O

OTR

Over the road: long-haul trucking across many states.

Oversize load

A load that exceeds standard legal size limits and needs a permit. See oversize and heavy haul.

Owner-operator

A driver who owns or leases their truck and runs their own business. See owner-operator vs company driver.

P

Pre-trip inspection

The safety inspection before driving. See pre-trip inspection.

R

Reefer

A refrigerated trailer.

RGN

Removable gooseneck, a lowboy trailer whose front detaches for loading.

Road train

A truck pulling several trailers, common in Australia. See giant machines.

Runaway ramp

An escape lane for trucks with failed brakes. See runaway truck ramps.

S

Scale house

A weigh station where trucks are weighed and inspected.

Sleeper berth

The sleeping area behind a truck's cab.

Slip seat

Sharing one truck among several drivers on different shifts.

Spread axle

A tandem with axles set farther apart to carry more legal weight in some states.

Step deck

A flatbed with a lower rear deck for taller cargo.

T

Tandem

A pair of axles close together.

Tanker

A trailer that carries liquids or gases. See tankers.

Team driving

Two drivers sharing one truck to keep it moving nearly nonstop.

Tractor

The truck unit that pulls a semi-trailer.

Trailer brake (trolley valve)

A hand valve that applies only the trailer brakes.

W

Weigh station

A roadside facility where officials check truck weights and safety.