Trucking Glossary

A braking system that uses compressed air, generally including service brakes for normal stops, parking brakes, and emergency braking functions for a system failure. A CDL “no air brakes” restriction relates to qualification and the test vehicle; it is not a separate air-brake certificate or endorsement.

Treat abnormal gauges, low-pressure warnings, air leakage, or brake response seriously. Perform the vehicle- and carrier-specific pre-trip check; passing air-brake knowledge testing does not prove that today's brake system is safe.

Also: 空气制动 · 气压制动 · air brake system · pneumatic brakes

A duct or structure directing air through a refrigerated trailer. Damage or obstruction can affect circulation.

Respect equipment and loading clearances; the chute is not storage space.

A location where a tiedown attaches to the vehicle or cargo. Its structure and condition affect securement.

A place that accepts a hook is not necessarily a suitable anchor.

A system that modulates brake pressure during hard braking to help prevent wheel lock and preserve steering control. ABS does not guarantee a shorter stop on every surface, create tire traction, or replace normal braking technique; tractor and trailer systems may have separate warning indicators.

Know which ABS lamps correspond to the tractor and trailer. If a lamp stays on, fails to illuminate when expected, or comes on while driving, follow vehicle and carrier inspection or repair steps; ABS is not a guarantee of stopping distance.

Also: 防锁死刹车 · 防抱死系统 · anti-lock brakes · antilock brakes

Auxiliary Power Unit: equipment supplying cab climate control or electrical power while parked, reducing main-engine idling. It may use diesel or batteries. Having an APU does not automatically satisfy California requirements; equipment emissions and operating restrictions still apply.

Also: Auxiliary Power Unit

Restraint using suitable structures or material to prevent load movement in a direction, usually as part of a complete securement arrangement.

Clarify which movement is restrained, not merely whether something fills a gap.

Using supports to stabilize cargo or resist movement. The supports and their connections must suit the forces involved.

Blocking and bracing may work together; packaging filler is not automatically structural restraint.

A device that tensions and holds a securement chain, also called a load binder, with different mechanisms and ratings.

Use compatible chain and connectors rather than matching by appearance.

Also: load binder

The heaviest federal vehicle class, GVWR > 33,000 lbs. This is the segment our association serves.

Also: 重卡 · 大卡车 · heavy-duty truck

A refrigeration mode involving continuous operation, commonly to maintain airflow; exact behavior depends on the unit.

Match the shipment instructions and unit; do not substitute a fuel-saving mode yourself.

Diesel Exhaust Fluid: a urea solution used by the SCR exhaust-treatment system to reduce nitrogen oxides. It goes in a dedicated DEF tank, not in diesel fuel. Low level, quality issues, or system faults can trigger warnings and power or speed limits depending on the vehicle and software.

Also: 车用尿素 · Diesel Exhaust Fluid · AdBlue

A cycle that removes frost from the evaporator. Its duration and controls depend on the refrigeration unit.

Check the indicated operating state before interpreting an isolated temperature reading.

A charge for investigating, testing or diagnosing a problem, potentially payable even when repair is not authorized.

Clarify scope, price and whether it is credited toward later repairs.

Time a vehicle is unavailable for transport because of repair, waiting or another cause. Payment for losses depends on applicable terms.

Confirm the estimated release time and communicate it as an estimate.

Diesel Particulate Filter: a device trapping particles in diesel exhaust. Regeneration burns off accumulated soot; remaining ash may require cleaning according to the manufacturer. Restriction or faults can reduce available engine power.

Follow the dashboard instructions and the applicable vehicle manual. Parked regeneration creates high temperatures; this definition is not an operating procedure or a universal schedule.

Also: Diesel Particulate Filter

A process that oxidizes accumulated soot in a diesel particulate filter under controlled conditions. Types and operating requirements vary.

Regeneration does not remove all ash or fix every fault; follow the specific manual.

Also: regen · parked regen

An axle receiving power to move the vehicle. A scale's drive-axle reading may total a group rather than each individual axle.

Check whether the ticket reports an axle or an axle group.

The most common enclosed trailer — for dry, room-temperature freight (e-commerce, retail, boxed goods).

Materials used to support, separate or protect freight, such as suitable timber or fillers. Not all dunnage performs the same restraint function.

Describe its location and purpose instead of only saying dunnage is present.

Protection at an edge where a tiedown contacts cargo, reducing abrasion or cutting. It does not replace adequate restraint capacity.

Check the contact point and protection condition, not merely whether protectors are carried.

A control-system restriction on available engine power or operation. Causes and severity depend on the vehicle and condition.

Describe warnings and behavior; not every derate means regeneration is needed.

A code recorded by a control system to identify a detected condition. It guides diagnosis but is not proof of a particular failed part.

Report the full code and symptoms rather than clearing it to hide a problem.

The disk-shaped coupling on the tractor that locks onto the trailer's kingpin.

An open flat platform trailer for oversized loads, building materials, steel, etc. Requires strong cargo securement skills.

The actual combined weight of tractor, trailer, occupants, fuel, equipment and cargo at that time, unlike the manufacturer's combination rating.

Use measured figures for actual weight; a rating is not a scale reading.

The manufacturer's weight rating for a vehicle combination. It is neither a current scale reading nor the sole legal road-weight limit.

Axles, tires, route limits and any permit conditions still require separate checks.

Gross Vehicle Weight Rating: the manufacturer’s loaded-weight rating for a single vehicle, including the vehicle, people, fuel, and cargo. It is not the current scale weight or cargo capacity. Road, axle, and combination-weight limits must be checked separately.

Also: 满载额定重 · Gross Vehicle Weight Rating

A front-end structure on a vehicle or loading platform. It may restrain forward cargo movement where the design and arrangement support that use.

A headboard does not automatically remove the need for other securement.

The metal pin on the front of the trailer that locks into the tractor's fifth wheel.

The pricing rate for labor, often per hour. The total also depends on billed hours and the agreed pricing method.

Ask about both the rate and billed hours, not just the hourly price.

Trailer rear wheels track inside the tractor's turning path.

The term does not replace driving training.

The weight of cargo carried; payload capacity in a specification means rated carrying capability. Actual cargo weight and allowable capacity are different questions.

Ask whether the figure is actual payload or payload capacity.

Preparing a trailer or product to a specified temperature before loading; clarify which is being cooled.

Do not assume the transport unit can quickly chill an already warm load.

Planned inspection and servicing based on time, mileage, use or manufacturer requirements to reduce preventable failures.

PM scope and intervals depend on equipment and the carrier's maintenance plan.

An internal product temperature measurement, especially in produce handling, distinct from air readings or the set point.

Use an authorized measurement method and record the reading type and units.

A webbing tiedown tensioned with a ratchet mechanism. Its capacity depends on the assembly and conditions of use.

Address cuts, wear or unclear markings under equipment and carrier requirements.

A temperature-controlled trailer for freight such as food or pharmaceuticals. Equipment may cool and, on some units, heat. Confirm the setpoint, operating mode, and power arrangements using the shipment instructions and equipment manual.

Also: 冷链车 · refrigerated trailer

A description of proposed work and expected charges before repair, distinct from the final invoice. Added work may require further agreement.

Separate diagnosis, parts, labor, taxes and estimated amounts.

A shop record of reported concerns, agreed work and service activity; terminology and layout vary.

State the symptoms to investigate instead of only asking to fix it.

Also: work order

Air returning from the cargo space to the unit. Its temperature describes part of the airflow, not every product.

Supply and return readings can differ; identify the displayed reading first.

A further weighing after an initial weighing, for example to check distribution after a loading adjustment. Commercial scale terms and charges vary.

Keep both tickets and compare individual readings as well as the total.

Service provided at the vehicle's location, distinct from towing to a shop and limited by available equipment and conditions.

Provide location, vehicle type and symptoms, then confirm suitability and callout charges.

External power supplied to a parked truck.

Connectors and charges vary by site and truck.

A trailer tandem assembly that can be repositioned along the frame to alter axle location and weight distribution. This may also affect length or spacing compliance.

Use the equipment procedure and route constraints, then verify by weighing; this entry is not an operating guide.

A mode that automatically stops and restarts a refrigeration unit under its control logic. Names and behavior vary by manufacturer.

It does not suit every cargo; a brand name is not a shipment instruction.

Also: start stop

An axle whose wheels steer the vehicle. Typical highway tractor scale tickets list the front steering axle separately.

Keep the steering-axle reading separate from the drive-axle group.

Air delivered from the refrigeration unit into the cargo space; its temperature is not a direct product measurement.

Label the reading supply air instead of sending only a number.

A group of two closely spaced axles, found on tractors as well as trailers. A trailer tandem equipped with a sliding mechanism can be repositioned as permitted to change axle-load distribution; not every tandem slides.

Also: 后双桥

The weight of a vehicle or container without the cargo being measured, under stated weighing conditions. Included fuel, people and equipment depend on the record.

Check that weighing conditions match before comparing tare figures.

A device that stores temperature readings over time, also called a data logger. Sensor placement affects what the record represents.

Include sensor location, time and units rather than one isolated value.

Also: data logger

The target temperature entered into a refrigeration controller. It is not the measured cargo temperature and does not guarantee uniform temperature throughout the trailer. A correct setpoint alone does not establish acceptable cargo temperature.

Confirm the shipment’s written temperature, °F or °C, and operating-mode instructions rather than reusing the previous load’s settings.

Also: 设定温度 · 冷机温度 · 设定值 · setpoint · set point · temperature setting

An assembly of straps, chains and associated connectors used to restrain cargo on a vehicle. Its application depends on the load and connections.

“Two tiedowns” is not a universal rule for every load.

The powered front unit that pulls the trailer — engine + cab. Common brands: Freightliner, Kenworth, Peterbilt, Volvo, Mack, International.

Also: 车头 · power unit

The unpowered cargo unit towed by the tractor. Types include dry van, reefer, flatbed, tanker, etc.

The axles supporting the trailer. A common scale ticket lists their group weight separately, while axle counts and layouts vary.

A trailer's total weight is not the same as its axle-group reading.

Cleaning of a trailer interior; sanitation and documentation requirements depend on prior cargo and the next shipment.

A wash receipt documents service, not universal compliance with food-transport requirements.

Ultra-low sulfur diesel meeting U.S. on-road standards.

Check pump labeling and vehicle requirements.

How vehicle and cargo weight is distributed across positions and axle groups. Equal total weights can produce different axle readings.

An acceptable total alone does not establish acceptable axle weights.

The maximum working load of a securement component under specified conditions, not its breaking strength. The system also depends on connections and use.

Check WLL, condition and application rather than judging strength by thickness.