TRUCK INDUSTRY TERMS & TRUCKING GLOSSARY

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- I -

Independent Trucker
See Owner Operator.

ITS (Intelligent Transportation Systems)
See IVHS.

IVHS (Intelligent Vehicle Highway Systems)
Blanket term for a wide array of technologies, including electronic sensors, computer hardware and software and radio communications. The purpose of IVHS is to increase efficiency of use of existing highways, reducing travel time, fuel consumption, air pollution and accidents. There are five functional areas:

•  Advanced Public Transportation Systems (APTS)
•  Advance Traffic Management Systems (ATMS)
•  Advance Traveler Information Systems (ATIS)
•  Advanced Vehicle Control Systems (AVCS)
•  Commercial Vehicle Operations (CVO)

A more recently coined term, Intelligent Transportation Systems (ITS), encompasses both IVHS and modes of transportation other than highway, such as rail.

- J -

Jackknife
To place the trailer at a very sharp angle to the tractor.

JIT (Just-In-Time)
Manufacturing system which depends on frequent, small deliveries of parts and supplies to keep on-site inventory to a minimum.

- K -

Kingpin (axle)
Pin around which a steer axle's wheels pivot.

Kingpin (trailer)
Anchor pin at the center of a semitrailer's upper coupler which is captured by the locking jaws of a tractor's fifth wheel to attach the tractor to the semitrailer.

- L -

Landing Gear
Retracting legs which support the front of a semitrailer when it is not coupled to a tractor.

LCV (Long Combination Vehicle)
In general, vehicles longer than a standard doubles rig (tractor and two 28-foot semitrailers). Examples of LCVs which are permitted in some U.S. western states and eastern toll roads: Twin 48-foot trailers; triple 28-foot trailers.

Lessee
Company or individual which leases vehicles.

Lessor
Company which leases vehicles.

Lift Axle
Extra, unpowered axle needed only when the vehicle is loaded, allowing it to meet federal and state vehicle weight standards. The lift axle is mounted to an air spring suspension that raises the axle when it is not required.

LPG
Liquid propane gas.

Load Range (Tires)
Letter code system for the weight carrying capacity of tires. Comparable ply ratings are shown below.

LR PR LR PR A
 
        .... 2 E .... 10 B .... 4 F .... 12 C .... 6 G .... 14 D ....
 
        8 H .... 16 (LR = Load Range PR = Ply Rating)

Logbook
Book carried by truck drivers in which they record their hours of service and duty status for each 24-hour period. Required in interstate commercial trucking by the U.S. Department of Transportation.

Lowboy
Open flat-bed trailer with a deck height very low to the ground, used to haul construction equipment or bulky or heavy loads.

LTL (Less-Than-Truckload)
A quantity of freight less than that required for the application of a truckload (TL) rate; usually less than 10,000 pounds.

LTL Carrier
Trucking company which consolidates less-than-truckload cargo for multiple destinations on one vehicle.

- O -

Overdrive
Gearing in which less than one revolution of a transmission's input shaft causes one turn of the output shaft. The purpose of overdrive is to reduce engine rpm in high gear for better fuel economy. Example: A transmission with an overdrive top gear has a ratio of 0.70 to one. Turning the input shaft 0.7 revolutions causes 1.0 revolution of the output shaft.

Owner-Operator
Trucker who owns and operates his own truck(s).

- P -

P&D
Pickup and delivery.

Payload
Weight of the cargo being hauled.

Peddle Run
Truck route with frequent delivery stops.

Pigtail
Cable used to transmit electrical power from the tractor to the trailer. So named because it is coiled like a pig's tail.

Piggyback
Semitrailer built with reinforcements to withstand transport by a railroad flatcar.

Pintle Hook
Coupling device used in double trailer, triple trailer and truck-trailer combinations. It has a curved, fixed towing horn and an upper latch that opens to accept the drawbar eye of a trailer or dolly.

Ply Rating (PR)
Relative measure of tire casing strength. (see Load Range)

Private Carrier
Business which operates trucks primarily for the purpose of transporting its own products and raw materials. The principle business activity of a private carrier is not transportation. (see For-Hire Carrier)

PSI (Pounds Per Square Inch)
In trucking, unit of measurement for tire air pressure, air brake system pressure and turbocharger boost.

PTO (Power Takeoff)
Device used to transmit engine power to auxiliary equipment. A PTO often drives a hydraulic pump, which can power a dump body, concrete mixer or refuse packer. Some designs mount to a standard opening on the transmission, while others attach at the front or rear of the engine.

Pull Trailer
Short, full trailer (supported by axles front and rear) with an extended tongue.

Pup Trailer
Short semitrailer, usually between 26 and 32 feet long, with a single axle.

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