3PL (Third-Party Logistics) – A company that provides outsourced logistics services for transportation, warehousing, and distribution. Many trucking companies work with 3PLs to manage shipments, freight brokerage, and supply chain coordination. Using a 3PL helps shippers save time, reduce costs, and improve efficiency.

3 Points of Contact – A safety rule for climbing in and out of a truck. Drivers should always keep three points of contact (two hands and one foot, or two feet and one hand) to prevent falls.

5th Wheel – The large coupling device mounted on the tractor that connects to the trailer’s kingpin. It allows the trailer to pivot during turns. Essential for safe operation of semi-trucks.

10-Hour Break – A required rest period under Hours of Service (HOS) regulations. Drivers must take 10 consecutive hours off duty (must be logged in Sleeper or off-duty) before starting a new driving shift. This rest time resets the 11-hour driving limit and allows the driver to legally start a new workday.

10-Speed Transmission – A manual transmission commonly found in older or standard trucks. It requires skill to shift gears in sequence, often using a splitter for half-gears.

11-Hour Driving Rule – A federal Hours of Service (HOS) regulation that limits truck drivers to a maximum of 11 hours of driving after taking 10 consecutive hours off duty. The 11 hours must be completed within the 14-hour workday window. This rule is enforced by FMCSA to prevent fatigue-related accidents.

14-Hour Rule – An HOS regulation that limits a driver’s workday to 14 consecutive hours after coming on duty, with a maximum of 11 of those hours spent driving. Breaks and off-duty time do not extend the 14-hour window.

30-Minute Break Rule – HOS rule requiring drivers to take a 30-minute break after 8 cumulative hours of driving without at least a 30-minute interruption.

34-Hour Reset (Thirty-Four Hour Restart) – A rule that allows drivers to reset their 60-hour/7-day or 70-hour/8-day clock by taking 34 consecutive hours off duty. Commonly used to “restart” the weekly driving limit.

48-Foot Trailer – A common trailer length in the U.S. Used for hauling freight where a full 53-foot trailer is not required or allowed.

53-Foot Trailer – The standard trailer length in modern trucking and the maximum allowed on most U.S. highways without special permits.

70-Hour Rule – An HOS regulation stating that a driver cannot drive after 70 hours of duty in any 8-day period. Time resets after an off-duty period (or with a 34-hour reset).

80,000-Pound Limit – The maximum legal gross vehicle weight for a tractor-trailer in the U.S. without requiring special oversize/overweight permits. This includes the weight of the truck, trailer, and cargo combined.

ABS (Anti-lock Braking System) – A safety system that prevents wheels from locking up during braking.

Accessorial Charges – Extra fees charged for services beyond standard pickup and delivery. Examples include detention pay (waiting time), layover, tarping, fuel surcharge, or lumper fees.

Adverse Driving Conditions Exception – An FMCSA rule that allows drivers up to 2 extra hours of driving time when unexpected bad weather, road closures, or other unforeseen conditions make it unsafe to stop. This extends the 11-hour driving limit but not the 14-hour on-duty clock.

Aggressive Driving – A traffic offense that usually combines multiple dangerous behaviors such as speeding, tailgating, and improper lane changes. For CDL drivers, this can result in CSA points and higher insurance costs.

Agricultural Inspection Station – A state-run checkpoint (commonly in states like Florida, California, and Arizona) where trucks carrying produce, plants, or livestock must stop. Inspectors check bills of lading and may inspect the load to prevent the spread of pests, diseases, or invasive species.

Air Brakes (CDL Manual) – Explains how air brake systems work, including dual air systems, inspections, air loss limits, and how to recognize brake problems.

Air Brakes (System) – The braking system used on most commercial trucks and buses. It works by using compressed air instead of hydraulic fluid. The system includes an air compressor, storage tanks, air lines, brake chambers, and components like glad hands that connect the tractor to the trailer. Drivers must do daily air brake checks and know the proper air pressure ranges, since low air pressure can cause the brakes to lock automatically.

Air Brakes Test – A written exam required if the truck uses air brakes. Covers how air brakes work, proper inspection, and safety checks. Without passing, the CDL will have an “L” restriction (no air brakes).

Air Compressor – The part of the truck that pumps air into the storage tanks for the air brake system. It is usually engine-driven and keeps enough pressure in the system to operate the brakes safely. During the CDL pre-trip, drivers must check that the compressor builds air pressure within the proper time limits.

Air Couplers – The connectors that attach the tractor’s air lines to the trailer’s air brake system. They lock together to form a sealed connection so compressed air can flow between tractor and trailer. Also known as [Glad Hands].

Air Governor – A component of the air brake system that controls when the air compressor pumps air into the tanks. It cycles the compressor on and off between cut-in and cut-out pressure levels.

Air Governor Cut-Out – The air pressure point (usually 120–135 PSI) where the governor tells the compressor to stop building air because the system is full.

Air Horn – A loud horn powered by compressed air, used to warn other drivers or pedestrians. On some trucks it’s mounted on the roof as chrome trumpets, while on others (newer aerodynamic models) it’s hidden inside the grille. Controlled by a switch or cord in the cab.

Air Lines – The hoses that carry compressed air between the tractor and trailer to control the brakes. They are usually color-coded: the red line is the emergency supply line, and the blue line is the service line. Drivers must check that air lines are properly connected, free of leaks, and not tangled or rubbing against other parts.

Air Miles – A mileage pay method some trucking companies use, based on the “shortest distance” between two zip codes (as if drawn in a straight line, or “as the crow flies”). This usually results in fewer miles than what the driver actually drove, so pay may be less than expected.

Air Ride (Suspension) – A type of suspension system that uses airbags instead of steel springs, giving the truck a smoother ride and helping protect freight from damage.

Air Tank – A metal tank that stores compressed air for the truck’s braking system. Trucks usually have multiple air tanks for safety.

Air Tank Drain Valve – The valve used to drain moisture and contaminants from the air tanks.

Alligator/Alligator Tail – A piece of blown tire tread lying in the road. Called this because it looks like an alligator’s back or tail and can be dangerous if hit. [View Image]

Annual Inspection Report / Sticker – Proof that a truck and trailer have passed the required DOT safety inspection within the last 12 months. The report is the paperwork filled out by the inspector, and the sticker is placed on the truck or trailer to show the inspection was done. Both may be checked during a DOT roadside inspection.

Anti-Freeze – A liquid added to a truck’s cooling system to prevent the engine coolant from freezing in cold weather and overheating in hot weather. Anti-freeze also contains corrosion inhibitors to protect the radiator and engine components.

AOBRD (Automatic On-Board Recording Device) – The older version of ELDs (Electronic Logging Devices), phased out in the U.S. in 2019.

Appointment Time – The scheduled time a driver is expected to arrive at a shipper or receiver for loading or unloading. Appointment times are set by the customer and are critical in certain freight like groceries or retail. Being late can cause rescheduling, detention, or even load refusal.

Applied Pressure Test – Part of the CDL air brake inspection; checking for air loss while brakes are applied.

APU (Auxiliary Power Unit) – A small engine that provides heating, cooling, and electricity without idling the truck.

Articulated Vehicle – A vehicle with two or more parts connected by a joint that lets it bend. In trucking, this means a tractor and trailer together. In buses, it’s the long “bendy buses” with a hinge in the middle. [View Image]

Atlas – A large book of maps (usually Rand McNally Trucker’s Atlas) that shows truck-approved routes, restricted roads, and low clearances. Still useful even with GPS.

ATA (American Trucking Associations) – A large national trade association that represents the trucking industry.

Authorized Passenger – A person who has been approved under a carrier’s rider policy to travel in the truck with the driver. This could include family members or friends, but only if the company has given written permission and proper documentation is carried in the truck.

Authority (Operating Authority) – Permission from the FMCSA that allows a carrier to haul freight for hire.

Automatic Truck – A semi-truck with an automatic transmission that shifts gears by itself. Many new trucks today are automatics, which makes driving easier for beginners.

Autonomous Truck – A truck that can drive itself using computers, cameras, and sensors instead of a driver.

Axle – The shaft that connects wheels on a truck or trailer. Axles carry the vehicle’s weight and help distribute loads evenly. Trucks may have steer axles, drive axles, and trailer axles.

Axle Weight – The weight carried by a truck’s individual axle(s), checked at weigh stations for legal limits and other certified scales to make sure loads are legal and balanced..

Back Door (Slang) – Refers to behind the truck. “Bear at your back door” means a cop is behind you.

Backhaul – A return load that a truck picks up on the way back from a delivery, so the truck isn’t driving empty.

Backing – The act of driving a truck in reverse. CDL tests include straight-line backing, offset backing, and alley dock backing.

Baffled Tank – A tanker with internal walls (baffles) that slow down the movement of liquid to reduce surge.

Balloon Freight – Freight that takes up a lot of space but doesn’t weigh much (like paper towels or empty bottles).

Balloon Payment – A large final payment due at the end of some lease-purchase agreements for a truck. Balloon payments can make lease-purchase programs risky if the driver isn’t prepared for the cost.

Bare Down – A CB expression meaning to watch out, pay attention, or get serious about the road ahead. Drivers may say it when approaching heavy traffic, bad weather, or law enforcement.

Base Plate – The main license plate for a commercial truck, issued under the International Registration Plan (IRP). It allows the truck to operate across multiple states without buying separate plates for each state.

Basic Control Skills Test – The exam where drivers demonstrate backing maneuvers such as straight-line backing, offset backing, and alley dock.

Bear – Trucker slang for a law enforcement officer, usually a state trooper or highway patrol.

Belly Dump (or Bottom Dump) Trailer – A dump trailer with doors on the bottom that release material while the truck is moving. Perfect for spreading gravel or asphalt evenly over a road surface.

Benefits – Extra perks drivers may receive from their company besides pay, such as health insurance, retirement plans, or paid time off.

Big Word (Slang) – CB talk for a long or fancy message.

Bill of Lading (BOL) – The legal document that lists what’s being shipped, who it’s going to, and serves as a receipt for the load.

Binder – Chains, straps, or devices used to tighten and secure loads (mainly in flatbed trucking).

Biometrics – The use of physical identifiers (such as fingerprints, facial recognition, or iris scans) for identity verification. In trucking, biometrics may be used for secure facility access, TWIC cards, border crossings, or electronic logging device (ELD) authentication.

Biosecurity Measures – Procedures required to prevent the spread of pests, diseases, or invasive species when moving freight, plants, or animals. For truck drivers, this can include cleaning trailers, inspecting equipment, carrying permits, or stopping at agricultural checkpoints in quarantine zones.

Black Ice – A thin, nearly invisible layer of ice on the road surface. It forms when moisture freezes quickly, often in shaded areas, bridges, or early mornings. Black ice is dangerous because drivers may not see it until traction is lost.

Blind Shipment – A shipment where the shipper and receiver don’t know each other’s identity. The bill of lading is altered so one or both parties see different information. Often used by brokers.

Blind Side Backing – Backing a truck toward the passenger side, where the driver has limited visibility. Because mirrors and windows don’t give a clear view, this maneuver is more challenging for new drivers.

Blind Spot – The areas around a truck that the driver cannot see with mirrors.

Blinker – Another word for the turn signal. Blinkers flash to indicate a left or right turn or lane change. Always use them early so other drivers know your intentions.

Blood Alcohol (BAC – Blood Alcohol Concentration) – The amount of alcohol in a driver’s bloodstream, measured as a percentage. For CDL holders, the legal limit is 0.04% (half the standard limit for passenger car drivers). Any detectable alcohol can result in penalties, suspension, or disqualification under DOT/FMCSA rules.

BlueParrott – A leading brand of Bluetooth headsets popular among truck drivers. Known for noise cancellation, long battery life, and comfort during long hauls. Often compared with Blue Tiger headsets as a top choice for hands-free communication.

Blue Tiger – A popular brand of Bluetooth headsets designed for truckers. Known for long battery life and comfort during long hauls.

Blowout – A sudden tire failure where the tire bursts, often causing loss of control. Blowouts are especially dangerous on steer tires.

Bobtail – Driving a tractor without a trailer attached.

Bonded Warehouse – A storage location approved by customs for holding imports before duties/taxes are paid.

Box Truck – A straight truck with a cargo area shaped like a large box, usually between 10 and 26 feet long. Commonly used for local deliveries, moving companies, or final-mile freight. In most cases, a smaller box truck can be driven with a regular license, but larger ones may require a Class B CDL. Example: The trucks you often see delivering furniture, appliances, or rental moving trucks like U-Haul.

Brake Chamber – A round metal container mounted on each axle that uses air pressure to push a rod and apply the brakes. A critical part of the air brake system that must be checked during inspections.

Brake Drum – A part of a drum brake system (common on trailers and older trucks). The brake shoes press against the drum to slow the wheel. Must be inspected for cracks or wear.

Brake Lights – The red lights on the rear of the tractor and trailer that come on when the brakes are applied. They warn other drivers that the truck is slowing down or stopping. During a CDL pre-trip inspection, drivers must check that brake lights work properly on both the tractor and trailer.

Brake Shoes – Curved friction material that presses against the brake drum to stop the wheel. Worn shoes must be replaced.

Bridge Formula – Federal rules that limit how much weight can be placed on axles depending on the distance between them.

Bridges Freeze First – A safety warning that bridges and overpasses freeze before regular roads. Because air circulates above and below the surface, bridges lose heat faster, making them more prone to ice and black ice.

Bridge Height – The posted clearance under a bridge or overpass. Truck drivers must always know their vehicle’s height and watch bridge signs to avoid getting stuck. Example: A truck that is 13’6” tall cannot fit under a bridge marked 12’9”.

Bridge Law – The federal and state weight regulations that control how much weight can be carried on a truck’s axles, based on how far apart the axles are.

Brights (High Beams) – Slang for high-beam headlights, used for extra visibility at night. Drivers must dim them for oncoming traffic.

Broker (Freight Broker) – A middleman who arranges freight between shippers and carriers for a fee.

Bulk Freight – Freight that is loose and not packaged (like grain, coal, or liquid in tankers).

Bulk Trailer – A general term for trailers designed to carry dry bulk materials like grain, cement, or fertilizer, often unloaded with pneumatic systems.

Bulkhead – A solid internal wall in a tanker or trailer that separates compartments. Reduces surge by limiting liquid movement.

Bunk – The sleeper bed(s) inside a truck cab where drivers rest.

Bunk Heater – A small heater in the sleeper bunk that keeps the cab warm without idling the truck’s engine. It runs on diesel from the truck’s tank and helps save fuel during cold weather.

Bushings – Rubber or metal sleeves that cushion joints in the suspension system (like leaf springs or torque arms). Worn or missing bushings are a common inspection violation.

Button Hook – A wide right turn where the trailer swings around a corner and cuts in tight. Drivers must use caution so the trailer doesn’t hit vehicles or objects.

Cab – The front part of the truck where the driver sits and operates the vehicle. It may be a day cab (no sleeper) or a sleeper cab (with a bunk for resting).

Cab Card – The registration card for a commercial truck that lists the states and provinces where the vehicle is allowed to operate. Carriers must keep the cab card in the truck at all times for DOT inspections.

Cab Lights – The amber lights mounted on top of the cab. They make the truck more visible and mark the vehicle’s height and width. Often called marker or clearance lights.

Cabover (COE) – A truck where the cab sits over the engine. Short and boxy design.

Caged Brake Chamber – A brake chamber that has been disabled using a caging bolt. This allows the truck to be moved (in an emergency) even if the spring brakes are locked. Used only for maintenance or towing.

Cargo Insurance – Insurance that covers the value of the freight being hauled. While FMCSA doesn’t mandate a federal minimum for most carriers, most brokers and shippers require at least $100,000 in cargo coverage before they’ll tender a load.

Cargo/Bunk Net – A safety net used inside the cab sleeper (bunk) to keep drivers or cargo from falling during sudden stops or crashes.

California Bridge Law – A state-specific law in California that limits the distance from a trailer’s kingpin to the rearmost axle (tandems) to 40 feet on most highways. This law is stricter than the federal Bridge Formula and is meant to improve turning ability and reduce wear on roadways. Drivers must often slide their tandems forward to stay legal in California. See Also: Kingpin-to-Rear-Axle (KPRA) Measurement.

Car Hauler – A trailer designed to haul multiple vehicles, often with upper and lower decks. Common in both new car transport and auctions.

Cargo Van – A smaller commercial vehicle with an enclosed cargo area, used for hauling lighter loads or expedited freight. Cargo vans don’t require a CDL and are often used for local deliveries, small packages, or time-sensitive loads in the expediting industry.

Cargo Weight – The weight of the load being hauled not counting the truck or trailer weight.

Careless Driving – Operating a vehicle without due caution, but without the intentional disregard that defines reckless driving. It’s considered less serious than reckless driving but can still impact a CDL record.

Carrier – A trucking company that moves freight.

CAT (Certified Automated Truck) Scale –A certified truck scale found at many truck stops. Shows the total weight of the truck and each axle.

Catwalk – The metal platform or steps behind the cab, above the frame, that drivers use to connect air lines and electrical cables to the trailer.

CB (Citizens Band) Radio – A CB is a two-way radio system that operates on 40 shared channels in the 27 MHz band. It’s limited by the FCC (Federal Communications Commission) to short-range communication (usually 3–20 miles depending on conditions). No FCC license is required. Truckers use CB radios for road updates, communication at truck stops, and emergencies.. Example: Drivers warn each other about accidents or “bears” (police).

CB Antenna – The antenna mounted on a truck that sends and receives CB radio signals. A good antenna setup is critical for clear communication with other drivers.

CB Check – A quick test where a driver keys up the CB microphone and asks for a radio check to make sure their CB is working and being heard by others.

CB Tuning – Adjusting a CB radio and antenna for the best performance and signal strength. Often done using an SWR (Standing Wave Ratio) meter to reduce interference and improve range.

CB Handle – A nickname or call sign a driver uses on the CB radio instead of their real name. Handles can be chosen by the driver or given by other drivers, and they help identify who’s talking without revealing personal details.

Chain Law – State rules that require trucks to carry and/or use tire chains during certain months or when road conditions are bad. Example: Colorado’s chain law requires commercial trucks to carry chains from September to May and to chain up during snowstorms.

Chaining Up – The process of putting chains on a truck’s tires to get better traction in snow or ice.

Channel 9 – The CB radio channel reserved for emergencies and motorists in distress. Drivers traditionally monitor this channel for accidents, breakdowns, or urgent calls for help.

Channel 19 – The main CB radio channel used by truckers across the U.S. It’s the standard channel for traffic updates, road conditions, and driver-to-driver communication on the highway.

Chassis – The base frame of a truck or trailer that holds the body and cargo.

Check Call – A required call or message from a driver to their dispatcher or company to give an update on their load status, location, or progress. Many carriers require daily check calls, or updates at specific times like after pickup, during transit, and at delivery.

Check-In – The process of reporting to the guard shack or shipping office when arriving at a shipper or receiver.

Check-Out – Getting paperwork signed and cleared before leaving with a loaded or empty trailer.

Chicken Coop (Slang) – A weigh station or inspection station.

Chicken Lights (Slang) – Extra decorative lights on a truck, usually on the cab or trailer.

Chicken Truck (Slang) – A truck with lots of chrome and lights; flashy rig.

Chicken Wing’n (Driver Elbow) – Slang for when a driver is cruising or backing with their elbow hanging out of the window.

Chicken Wing’n (Trailer Tracking) – Slang for when a trailer isn’t tracking straight behind the tractor, often due to poor setup while backing.

Citation – A ticket issued for violating traffic or trucking laws, such as speeding, overweight, or logbook violations.

City Horn – A standard, quieter horn used for city driving situations where an air horn would be too loud.

Class 1 Truck (Light-Duty) – The smallest class of trucks, usually passenger-style vehicles like small SUVs or vans under 6,000 lbs. These don’t require a CDL.

Class 2 Truck (Light-Duty) – Slightly larger vehicles, such as pickups, full-size SUVs, or small delivery vans with a weight up to 10,000 lbs. Still no CDL needed.

Class 3 Truck (Light-Duty/Medium Crossover) – Box trucks, small flatbeds, and utility service trucks. These are often used for local deliveries (think UPS-style trucks).

Class 4 Truck (Medium-Duty) – Larger box trucks, step vans, or small dump trucks. They usually weigh between 14,001–16,000 lbs.

Class 5 Truck (Medium-Duty) – Trucks like larger delivery vehicles, walk-in trucks, or bigger dump trucks. Weight range is 16,001–19,500 lbs.

Class 6 Truck (Medium-Duty) – Single-axle trucks like school buses, beverage trucks, and some larger box trucks. GVWR is 19,501–26,000 lbs. At this weight, some drivers may need a CDL depending on the state and use.

Class 7 Truck (Heavy-Duty) – Heavier commercial trucks like city buses, tow trucks, and refuse (garbage) trucks. These weigh 26,001–33,000 lbs. CDL required.

Class 8 Truck (Heavy-Duty Tractor-Trailers) – The big rigs of the highway. Anything over 33,000 lbs GVWR, including semis, long-haul trucks, dump trucks, and specialized rigs. This is the class most CDL drivers operate.

Clearance Lights – Small amber or red lights mounted on the top edges and sides of a truck or trailer. They show the height and width of the vehicle so other drivers can see it at night or in poor visibility.

Clearance Height – The total height of a truck or trailer from the ground to the highest point (often the trailer roof or an exhaust stack). Drivers must always know their clearance height to avoid hitting low bridges or overpasses.

Clevis Pin & Cotter Pin – Small locking pins that connect brake components, such as the slack adjuster to the pushrod. They must be present and secure during pre-trip inspections.

Cobra (Electronics Brand) – A popular brand that makes trucking electronics such as CB radios, dash cams, and radar detectors. One of the most popular is the Cobra 29 LTD Classic CB Radio, known for its durability and reliability. It has been a favorite among truckers for decades and is still widely used on the road today.

Combination Vehicle – A truck made up of two or more units connected together. The most common example is a tractor pulling a trailer (semi-truck), but it can also mean a truck pulling doubles or triples. Drivers need a Class A CDL to operate combination vehicles.

Combination Vehicles – Explains how tractor-trailers work together. Covers coupling/uncoupling, rollover risks, trailer skid control, and safe braking.

Combination Vehicles Test – A written exam required for anyone pulling a trailer. Covers coupling/uncoupling, trailer handling, rollover prevention, and braking systems.

Comdata – A financial services company widely used in trucking. Issues fuel cards, payroll cards, and money codes for paying lumpers and other expenses. One of the most recognized names in driver payment systems.

CDL (Commercial Driver’s License) – The special license needed to drive commercial trucks.

CDL Class A – License to drive the big rigs. Covers tractor-trailers, semi-trucks, and any combination vehicle over 26,001 lbs with a trailer heavier than 10,000 lbs. Example: Driving a standard 18-wheeler (truck and trailer) across state lines.

CDL Class B – License for single vehicles over 26,001 lbs, or a vehicle pulling a trailer under 10,000 lbs. Example: Driving a straight truck, dump truck, or a city bus.

CDL Class C – License for smaller vehicles that carry 16 or more passengers, or vehicles hauling hazardous materials. Example: Driving a HazMat delivery truck or a passenger van.

CDL P (Commercial Driver’s License Permit) – A learner’s permit that allows you to practice driving a commercial vehicle with a licensed CDL driver in the passenger seat. You must get your CDL Permit before testing for your full CDL license.

CDL Restrictions – Limits placed on a commercial driver’s license that tell what you cannot drive or how you can operate a truck. Restrictions depend on the type of vehicle you tested in or special rules in your state.

CDL Restriction E – A restriction placed on a CDL if the driver takes the skills test in a truck with an automatic transmission. It means the driver is only allowed to drive trucks with automatic transmissions and cannot operate manual-shift trucks.

CDL Restriction K – A restriction placed on a CDL that limits the driver to intrastate driving only. This means the driver can operate commercial vehicles, but only within one state and not across state lines.

CDL Restriction L – A restriction placed on a CDL if the driver takes the test in a truck without air brakes. It means the driver cannot operate commercial vehicles that are equipped with full air brake systems.

CDL Restriction M – A restriction placed on a CDL that means the driver cannot operate Class A passenger vehicles, such as very large city buses that bend in the middle.

CDL Restriction N – A restriction placed on a CDL that means the driver cannot operate Class A or Class B passenger vehicles.

CDL Restriction O – A restriction placed on a CDL if the driver takes the test in a truck that is not a tractor-trailer. It means the driver cannot operate tractor-trailers.

CDL Restriction Z – A restriction placed on a CDL if the driver takes the test in a truck with air-over-hydraulic brakes. It means the driver cannot operate commercial vehicles with a full air brake system.

Commercial Motor Vehicle (CMV) – Any truck or bus used for business that weighs over 10,001 lbs, carries 9+ passengers for pay, 16+ passengers not for pay, or hauls hazardous materials.

Commercial Truck Route – Specific roads and highways designated for commercial vehicles. Routes avoid low bridges and restricted areas.

Commercial Zone – A set area around a city, defined by federal law, where trucking has special operating rules. Example: Driving from Kansas City, MO to Kansas City, KS may count as a local haul inside the Kansas City commercial zone.

Common Carrier – A for-hire trucking company that transports goods for multiple customers under government authority. Common carriers are required to provide services to the public at published rates and follow federal transportation regulations.

Conestoga Trailer – A flatbed trailer with a retractable rolling tarp system that covers the freight, similar to a curtain-side trailer. The tarp system protects cargo from weather while still allowing side and rear loading. Named after the covered wagons of the 1800s.

Consignee – The person or company receiving the load. Example: Walmart is the consignee for many refrigerated shipments.

Consignor – The person or company who sends the freight/load.

Consolidated Shipment/Load – Combining multiple smaller shipments into one trailer to improve efficiency and reduce costs.

Container – A standardized metal box used to transport freight, most commonly seen in intermodal shipping (rail, ship, and truck). Containers usually come in 20-foot, 40-foot, or 45-foot lengths. They are carried on chassis trailers when hauled by trucks. Containers are commonly sealed and can hold anything from manufactured goods to raw materials.

Container Chassis (Chassis Trailer) – A skeletal trailer built to carry shipping containers from ports, rail yards, or intermodal hubs.

Contract Carrier – A trucking company that hauls freight only for specific customers under contract.

Controlling the Intersection – A defensive driving practice where truck drivers approach intersections cautiously, anticipating other drivers’ mistakes.

Conventional Sleeper – A type of truck cab that has an extended section behind the driver’s seat with a built-in bunk or small living space. Unlike a day cab, a conventional sleeper is designed for long-haul drivers who spend nights on the road. Sleepers may include a bed, storage compartments, and sometimes amenities like power outlets, refrigerators, or TVs.

Converter Dolly (Dolly) – The small trailer with a fifth wheel used to connect a second or third trailer in doubles/triples.

Convex Mirror – A curved mirror that gives a wide-angle view to reduce blind spots. Often mounted below or beside flat mirrors.

Convoy – A group of trucks or vehicles traveling together, usually headed in the same direction. Convoys can be informal (drivers running together for safety or company) or organized (such as for awareness events, military, or disaster relief).

Coolant – The liquid mixture (usually water and anti-freeze) that circulates through the engine to absorb heat and prevent overheating. Must be checked regularly at the reservoir and maintained at proper levels.

Coolant Additive (SCA / Supplemental Coolant Additive) – A chemical added to engine coolant to prevent rust, corrosion, and cavitation in the cooling system. Many trucks require SCAs to keep the cooling system working properly.

Corridor – In trucking, a corridor is a major freight lane or highway route that carriers use all the time. Think of it like a “superhighway for freight” where trucks are constantly moving loads back and forth (for example, the I-40 corridor from California to North Carolina). Companies often set up dedicated runs in these high-traffic corridors because freight is steady there.

CPAP Machine (Continuous Positive Airway Pressure) – A medical device commonly prescribed to drivers with sleep apnea. It delivers a steady flow of air through a mask to keep the airway open during sleep. Using a CPAP machine helps drivers get proper rest and is often required to stay medically qualified for a CDL. Drivers must show proof of compliance with CPAP treatment during DOT physicals if diagnosed with sleep apnea.

CPM (Cents Per Mile) – A common way drivers are paid, based on the number of miles they drive. Example: $0.55 CPM means the driver earns 55 cents for each mile.

Crack the Whip Effect – A dangerous rollover risk in doubles/triples where the last trailer swings or flips from sudden steering changes.

Crimped Line – An air line or electrical line that has been pinched, bent, or damaged so that flow is restricted. A common pre-trip inspection defect.

Critical Event – An incident automatically recorded by a truck’s onboard system, such as hard braking, sudden acceleration, lane departure, speeding, or collision warnings. Carriers use critical event reports to monitor driver safety and may review dash cam footage when events are triggered. Too many critical events can lead to coaching or disciplinary action.

Cross-Dock – When freight is unloaded from one trailer and immediately reloaded into another, instead of being stored in a warehouse.

Cross Members – Horizontal steel beams that run across the trailer’s frame, supporting the trailer floor and structure. CDL inspections require checking for cracks or missing cross members.

CSA Points – Points assigned under the Compliance, Safety, Accountability (CSA) program managed by FMCSA. CDL drivers and motor carriers receive CSA points when violations are recorded during roadside inspections, crashes, or compliance audits. The points vary depending on the severity of the violation and affect both the driver’s personal record and the carrier’s safety score. Too many CSA points can lead to more frequent inspections, higher insurance rates, and even suspension or termination of a CDL driver.

CSA Score (Compliance, Safety, Accountability Score) – A safety measurement system used by the FMCSA to track carriers and drivers. Scores are based on inspections, violations, and crash reports in categories like vehicle maintenance, hours of service, driver fitness, and controlled substances. High scores mean more inspections and higher insurance costs.

Curtain-Side Trailer – A flatbed trailer with a retractable curtain system that allows side loading and unloading while still protecting freight from the weather.

Custom Sleeper / Condo Sleeper – Large, often luxurious sleepers (sometimes 100+ inches long) with extra amenities like a TV, microwave, shower, or workstation. Popular with owner-operators running long-haul.

Customer – In trucking, the company or party that ships or receives the freight. Dispatch often refers to shippers and receivers as “customers.” For example, you may hear, “Call the customer when you get close,” meaning contact the shipper or receiver about your arrival.

Cut-In Pressure – The air pressure level where the governor tells the air compressor to start pumping air back into the system. In most trucks, this happens around 100 PSI.

Cut-Out Pressure – The air pressure level where the governor tells the air compressor to stop pumping because the system is full. This usually happens between 120–135 PSI.

DAC Report – Short for Drive-A-Check, this is a detailed report on a driver’s employment history in the trucking industry, maintained by HireRight. It includes information on past employers, accidents, drug tests, and safety performance. Most large carriers check DAC reports when hiring drivers.

Dash Cluster – The panel of gauges and indicator lights on a truck’s dashboard.

Dashcam – A camera mounted inside the cab that records video of the road (and sometimes the interior). Dashcams are used for safety, accident evidence, and driver training.

Day Cab – A tractor without a sleeper compartment, used for short-haul or local routes.

Deadhead – Driving with an empty trailer after dropping off a load.

Dedicated Route – A trucking route or customer assignment where a driver hauls the same freight regularly, instead of running random loads.

Deductions – Amounts taken out of a driver’s paycheck, such as taxes, insurance, fuel advances, or lease payments for owner-operators.

Defensive Driving – A driving style where the driver stays alert, predicts hazards, and keeps extra space around the truck to avoid accidents.

Delivery Appointment – The scheduled time a driver must arrive at the receiver to unload freight. Being late can lead to delays or rescheduling.

Delivery Number – A reference number assigned by the receiver that confirms a load is being delivered. Drivers often need to provide this number at the guard shack or receiving office before unloading.

Detention Time – Extra time a driver waits at a shipper or receiver beyond the agreed loading/unloading window. Often unpaid unless the carrier bills for it.

Detour Route – A change in route due to road closures, construction, or accidents. Dispatch or GPS usually provides updated directions.

DEF (Diesel Exhaust Fluid) – A liquid made from urea and deionized water that is injected into the exhaust system of modern diesel trucks. It helps break down harmful nitrogen oxide (NOx) emissions into harmless nitrogen and water. Trucks with SCR (Selective Catalytic Reduction) systems cannot run without DEF — if the DEF tank runs empty, the truck will go into reduced power mode until it’s refilled. DEF is sold at most truck stops in jugs or at the pump.

Diesel Fuel – The primary fuel used in commercial trucks. Diesel is denser than gasoline and provides more torque, making it ideal for heavy loads and long-distance hauling.

Diesel Burn Point – The temperature at which diesel fuel ignites. Typically around 410°F (210°C), though it can vary depending on the fuel blend. Important for understanding fire safety and engine combustion.

Diesel Rating (Cetane Rating) – A measurement of how easily diesel fuel ignites under compression. A higher cetane number means quicker ignition, smoother engine operation, and better cold-weather performance.

Differential – A set of gears inside the axle that allows the truck’s wheels to rotate at different speeds, especially while turning. Without a differential, the inside and outside wheels would spin the same, causing tire wear and handling problems. Trucks may have multiple differentials (on drive axles) and a switch in the cab to lock them together for traction in slippery conditions.

Differential Lock – A switch in the cab that locks the differential gears together so both wheels on the same axle (or both drive axles) turn at the same speed. Used to improve traction on snow, ice, mud, or slippery surfaces. Drivers should only use the diff lock at low speeds and disengage it once traction is restored to avoid damage.

Disconnect – Unhooking the tractor from the trailer, either for parking, repairs, or switching loads.

Dispatch / Dispatcher – The person at the trucking company who assigns loads and communicates with drivers about schedules and freight.

Distribution Center (DC) – A large facility where freight is received, sorted, and shipped out to stores, customers, or other locations. Truckers often pick up or deliver loads at DCs, which are common in retail and grocery supply chains.

DNH (Do Not Hire) – A note or designation carriers use in a driver’s record (such as on a DAC Report) meaning the driver is not eligible for rehire with that company. This can follow a driver to future job applications if shared through background reports.

Dock – The area at a warehouse or customer facility where trucks are loaded or unloaded. Drivers often have to back into tight docks.

Dock Plate – A metal plate used to bridge the gap between a trailer and the loading dock so forklifts or pallet jacks can move freight safely across. Dock plates are usually movable and lighter than permanent dock levelers.

Dock Ramp – A raised platform at shippers/receivers used for loading/unloading freight. Can also mean highway on/off ramps.

Dolly – A small two-wheel or four-wheel converter used to connect two trailers in a doubles or triples setup.

DOT – The U.S. Department of Transportation is the federal agency that oversees all forms of transportation in the U.S., including highways, rail, air, and maritime. Trucking falls under its authority through the FMCSA, which sets and enforces rules for commercial motor vehicles. See also: FMCSA.

DOT Inspection – A safety inspection done by DOT officers at weigh stations or roadside. Inspections range from paperwork-only to full vehicle checks.

DOT Physical Exam (Department of Transportation Physical Exam) – A medical examination required by the FMCSA for all CDL drivers to ensure they are healthy enough to operate a commercial motor vehicle safely. The exam must be performed by a certified medical examiner and covers vision, hearing, blood pressure, heart and lung health, and conditions such as diabetes or sleep apnea. Passing the DOT physical results in a Medical Examiner’s Certificate (MEC), often called a DOT Medical Card, which drivers must carry and keep current to stay qualified. See also: DOT Medical Card, Medical Examiner’s Certificate (MEC).

Double Bunk Sleeper – A sleeper designed with two bunks, one above the other, so two drivers can rest during team driving.

Double Blind Shipment – A shipment where both the shipper and receiver are kept anonymous from each other, with paperwork routed through a broker or third party.

Double Clutching – A shifting method required for CDL skills tests when driving a manual transmission. The driver presses the clutch twice for each gear change: once to move the shifter into neutral and again to put it into the next gear. This helps match engine speed to transmission speed and prevents gear grinding.

Double Drop Trailer (Lowboy) – A flatbed-style trailer with two drops in deck height, allowing very tall loads to be hauled legally.

Double Nickel (Slang) – 55 mph speed limit or driver speed.

Doubles / Triples (CDL Endorsement T) – Special endorsement on a CDL that allows a driver to pull two or three trailers at once.

DPF (Diesel Particulate Filter) – A filter in the exhaust system that traps soot and fine particles from diesel engines. To prevent clogging, the filter must go through regeneration (regen), which burns off the buildup at high temperatures. If the DPF gets too full, drivers may see warning lights and need to perform a parked or forced regen.

Drayage – The short-haul movement of containers between ports, rail yards, and nearby warehouses. Drayage is a key part of intermodal shipping and often involves waiting in lines at ports or rail terminals. Drivers who perform this work are sometimes called “drayage drivers.”

Dragon Wagon (Slang) – A tow truck.

Drive Axle – The axle(s) on a truck that deliver power from the engine to the wheels. On a semi, these are usually the rear axles of the tractor.

Drive Shaft – The rotating shaft that transmits power from the transmission to the drive axles, turning the wheels.

Drive Tires (Drives/Drive Axle Tires) – The tires mounted on the drive axles of the tractor, usually found on the rear of the cab. These tires provide the traction and power to move the truck since the engine drives this axle.

Driver Assist – When a driver is required to help load or unload freight, such as using a pallet jack or helping count product.

Driver Complaint (Public Complaint) – When a member of the public contacts a trucking company to report unsafe or unprofessional driving, such as cutting off a car, speeding, or reckless lane changes. Many trucks display “How’s My Driving?” decals with a phone number for this purpose. Complaints are logged by safety departments and may affect a driver’s record.

Driver ID/Number – A unique ID number assigned to each driver by their carrier. Used for dispatch, payroll, and tracking trips.

Driver Manager – Another term for dispatcher, usually the person assigned to oversee a driver’s loads, schedule, and communication with the company.

Driver Relay/Swap – When one driver hauls a load part of the way, then drops it at a terminal or meeting point for another driver to continue the trip. Relays help carriers keep freight moving while staying within hours-of-service limits.

Driver Side (Sight Side) Backing – Backing a truck toward the driver’s side (left side). Safer than blind side backing because the driver has a clear line of sight.

Driver Vehicle Inspection Report (DVIR) – A report drivers complete before and after trips to check the truck’s condition (brakes, lights, tires, etc.).

Driving Out of Class – A violation that occurs when a driver operates a vehicle requiring a higher CDL class or endorsement than they hold (for example, driving a tractor-trailer with only a Class B license).

Driving With a Disqualified CDL – Operating a commercial vehicle while the CDL is suspended, revoked, or otherwise disqualified. This is a major violation that can lead to extended disqualification periods.

Driving Without a CDL – A serious charge for operating a commercial motor vehicle without holding a valid CDL. Penalties can include fines, vehicle impoundment, and CDL disqualification.

Drop – The act of leaving a trailer at a yard, terminal, or customer location. Drivers may “drop” a loaded trailer for the receiver to unload later, or drop an empty trailer for a shipper to load. Often used in drop-and-hook operations.

Drop and Hook – A common type of freight move where a driver drops off a loaded trailer and immediately hooks up to a different trailer (saves time vs live load/unload).

Dropped Trailer (Accident) – When a trailer separates from the tractor because it wasn’t properly connected to the fifth wheel. This usually happens if the kingpin isn’t locked, the landing gear wasn’t checked, or a tug test wasn’t performed. Considered a preventable accident.

Dropped Trailer (Yard/Drop) – When a trailer is intentionally left at a customer, yard, or terminal instead of being live loaded/unloaded. Drivers “drop” their trailer and may later “hook” to a different one. Common with drop-and-hook loads.

Drug & Alcohol Clearinghouse – An online database managed by the FMCSA that tracks CDL drivers’ drug and alcohol testing results. It contains records of pre-employment, random, post-accident, and return-to-duty tests. Carriers are required to check the Clearinghouse before hiring and report violations. Drivers can also access their own records through the Clearinghouse.

Drug Screen – A federally required drug test for CDL drivers, usually urine or hair follicle testing. Needed for pre-employment, random checks, and after accidents.

Dry Van – The most common type of trailer, a standard enclosed box trailer used to haul general freight that doesn’t require refrigeration.

Dual Air System – A truck braking system with two separate air brake circuits. If one system fails, the other still provides braking power for safety.

DUI (Driving Under the Influence) – A violation for operating a vehicle while under the influence of alcohol or drugs. For CDL drivers, the legal blood alcohol limit is 0.04%, half the standard for non-commercial drivers. A DUI can lead to immediate out-of-service orders, heavy fines, CSA points, and CDL disqualification.

Dump Trailer (End Dump) – A trailer with a hydraulic lift that tips back to unload bulk materials like dirt, gravel, or asphalt.

Dump Truck – A commercial truck with an open bed that tilts to unload loose materials like gravel, sand, or dirt. Usually requires a Class B CDL, but larger ones pulling trailers may require Class A.

DWI (Driving While Intoxicated) – A traffic charge used in some states instead of DUI. It carries the same meaning: operating a vehicle while impaired by alcohol or drugs. For CDL holders, penalties are the same as a DUI, including possible suspension or permanent disqualification after repeat offenses.

DYNO (Dynamometer) – A DYNO is a piece of shop equipment that tests how strong a truck’s engine is. It’s like a treadmill for your truck, the drive wheels spin rollers while the DYNO measures horsepower, torque, and overall performance. Mechanics use it to find problems and check if repairs worked.

E-Log (Electronic Logbook) – A digital version of a driver’s hours-of-service (HOS) log. It can be kept on a tablet, computer, or software system. E-logs replaced paper logs but aren’t always tied directly to the truck.

Eaton Fuller – A well known brand of heavy duty manual transmissions used in many commercial trucks. Eaton Fuller transmissions range from simple 5-speeds to advanced multi-speed systems like the Super 10, 13-speed, and 18-speed. Known for durability and control, they allow drivers to split gears for better fuel efficiency and pulling power on grades.

Edge Line (Fog Line) – The solid white line painted on the far right side of the road that marks the boundary of the driving lane. Called the “fog line” because it helps drivers stay on the road in low visibility conditions like fog, rain, or snow. Unlike lane lines, the fog line is continuous and not broken.

EFS (Electronic Funds Source) – A company that provides fuel cards, money transfers, and payment systems for truck drivers and carriers. Commonly used for fuel, lumper fees, and cash advances.

Electrical Connector (Pigtail) – The coiled cable that supplies electrical power from the tractor to the trailer (for lights and ABS).

ELD (Electronic Logging Device) – A device connected to the truck’s engine that automatically records driving time, mileage, and HOS. The ELD mandate requires most commercial trucks to use these instead of stand-alone e-logs.

Eighteen Wheeler – Slang for a tractor-trailer with 18 wheels (10 on the tractor, 8 on the trailer).

Emergency Brake – Also called the parking brake. In trucks, it’s air-powered and applied when the red trailer brake knob is pulled.

Emergency Brake System – The part of the air brake system that uses spring brakes to stop the truck if air pressure gets too low or the emergency line fails.

Emergency Equipment – The required safety items that every commercial truck must carry under federal law. Examples: a fire extinguisher, reflective triangles or flares, and spare fuses.

Emergency Line – The red airline that supplies air to a trailer and controls the trailer’s emergency brakes. If the line breaks or loses pressure, the trailer brakes automatically lock.

Emergency Parking – Parking on the shoulder or roadside during breakdowns or emergencies. Drivers must set out warning triangles within 10 minutes, following DOT placement rules.

Emergency Response Guidebook (ERG) – A handbook carried in trucks hauling hazardous materials. It gives instructions on what to do in case of a spill or accident.

Empty – The term used when a trailer has no freight inside. Drivers tell dispatch they are “empty” after unloading, meaning they are ready for their next assignment. Sometimes logged as an “empty call” or “empty message” in the company system.

Empty Call / Empty Message – A message sent by the driver through the onboard computer or app after delivering a load, telling dispatch they are empty and ready for the next load assignment.

Empty Miles – The miles driven with an empty trailer, usually after delivering a load, returning to a terminal or picking up the next one. Also called deadhead miles. Carriers track empty miles closely because they don’t generate revenue but still use fuel and hours.

Empty Weight (Tare Weight) – The weight of the truck or trailer when it is empty, with no cargo. Important for calculating how much freight can be legally loaded. Often listed on the door sticker or paperwork.

Endorsement – A special authorization on a CDL that allows a driver to haul specific loads (like hazmat, tankers, doubles/triples, passengers).

Engine Braking – Using the truck’s engine to slow down instead of relying only on service brakes. Common types are Jake Brakes or exhaust brakes.

Entrance Ramp – The lane that lets vehicles enter a highway or interstate. Truck drivers must watch for merging traffic, accelerate to highway speed, and safely merge with other vehicles.

Equipment Breakdown – A mechanical failure that prevents the truck from operating, often leading to road service or shop repairs.

Ergonomic Seat – A seat designed to support the natural curves of the spine, reduce fatigue, and provide adjustability (lumbar support, recline, cushion tilt). These are common in long-haul trucks to reduce back pain.

Escrow – Money that a carrier may hold back from an owner-operator’s pay to cover potential expenses like equipment damage, insurance deductibles, or lease-related costs.

Escort Vehicle (Pilot Car) – A car or pickup that drives in front of or behind an oversized load to warn other traffic and help the truck maneuver safely.

Exempt Commodities – Certain agricultural products not regulated the same way as other freight under federal rules.

Exhaust Brake – A system that uses engine exhaust pressure to help slow the truck, reducing wear on service brakes. (Often grouped with “engine braking,” but can stand alone as its own entry.)

Exit Ramp – The lane that leads vehicles off a highway or interstate. Many exit ramps are sharp curves with reduced speed limits, so truck drivers must slow down early to prevent rollovers.

Expedite / Expedited Freight – Time sensitive freight that must move quickly, often handled by cargo vans, straight trucks, or team drivers.

Extended Cab/Sleeper – A sleeper cab that’s larger than standard, sometimes equipped with extra amenities like a fridge, microwave, or small bathroom for long-haul comfort.

EZ Pass (or Electronic Tolling) – An electronic device mounted in the truck that automatically pays tolls when passing through toll plazas. Used in many regions of the U.S.

Factoring – A financial service where a trucking company sells its unpaid freight bills to a factoring company for immediate cash. Helps drivers and small carriers cover fuel and expenses while waiting for shippers or brokers to pay.

Failure to Maintain Lane – A moving violation where a driver swerves, drifts, or otherwise fails to stay within marked lanes. For truck drivers, this is often cited when weaving or driving fatigued.

Failure to Yield – A violation issued when a driver fails to give right-of-way as required by traffic laws. For CMVs, this often happens when merging onto highways or turning at intersections.

Fairing – Aerodynamic panels on a tractor or trailer (often on the sides or roof) that reduce wind resistance and improve fuel economy.

Fan Down Test – Part of the CDL air brake pre-trip inspection. The driver fans (pumps) the brake pedal to lower air pressure, checking when warning alarms activate and when the spring brakes engage.

Feathering the Brakes – Lightly and repeatedly pressing the brakes to control speed on slick roads or steep grades, without locking up wheels.

Fender Mirror (Spot Mirror) – Small mirrors mounted on the truck’s fenders to give visibility of the area beside the hood and steer tires.

Final Mile (Last Mile) – The last leg of a delivery, usually from a terminal or hub to the customer. Common in local delivery jobs.

Fifth Wheel (5th Wheel) – The large coupling device mounted on the tractor that connects to the trailer’s kingpin. It allows the trailer to pivot while turning.

Fifth Wheel Locking Jaws – The locking mechanism inside the fifth wheel that clamps around the trailer’s kingpin. Drivers must confirm the jaws are fully engaged during pre-trip inspections.

Fifth Wheel Grease – A heavy-duty lubricant applied to the top of the tractor’s fifth wheel plate. It allows the trailer’s kingpin and skid plate to pivot smoothly during turns, preventing metal-on-metal wear. Fifth wheel grease reduces friction, noise, and damage to both tractor and trailer components.

Fifth Wheel Puller – A long metal rod with a fork or hook at the end, used to pull the fifth wheel release handle safely. It keeps drivers from having to climb under the trailer and reduces the risk of injury.

Fifth Wheel Skid Plate – The flat steel plate on the bottom of the trailer that rests on the fifth wheel. Provides a smooth surface for turning.

Fifty-Three (53 ft Trailer) – The most common trailer length in long-haul trucking. Standard for full truckload freight.

Fire Extinguisher – Required emergency equipment in every truck. Must be fully charged, rated, and easily accessible. Checked during pre-trip inspections.

Firestone – A major tire brand commonly used on commercial trucks and trailers.

Firewall – The solid barrier between the engine compartment and the cab of the truck. It protects the driver from engine heat, noise, and fire in case of an emergency.

Fixed Tandems – Trailer axles that cannot be slid forward or backward to adjust weight distribution. Opposite of sliding tandems.

Flagging – Using red or orange flags attached to wide or long loads (or extending cargo) to alert other drivers, as required by law.

Flare – A safety device that burns with a bright red flame when lit, used to warn other drivers of a stopped truck or accident. Flares can be used instead of reflective triangles as long as they meet DOT requirements. Many drivers still carry them for extra visibility at night or in poor weather.

Flat Mirror – The standard rectangular side mirrors that provide a direct view of traffic behind and beside the truck.

Flat Top Sleeper – A sleeper cab with a flat, low roof. Offers less headroom but is more aerodynamic and common on older or specialty rigs.

Flatbed Trailer – A type of trailer with no sides or roof, used for hauling oversized or irregular loads. Freight must be secured with chains, straps, and tarps.

Fleet Manager – A company employee who oversees a group of drivers, their loads, and schedules (similar to a dispatcher but often with more authority).

Fleet Owner – An owner-operator who owns multiple trucks and hires drivers to operate them.

Fleet One – A fuel card and payment company, now part of WEX. Common with smaller carriers and owner-operators.

Floating Gears – A shifting technique used in manual transmissions where the driver changes gears without using the clutch. Instead, the driver carefully matches engine RPM with road speed to slip the transmission into the next gear. It requires skill and practice, and while common among experienced drivers, CDL tests usually require double-clutching instead of floating.

Flying J – A major U.S. truck stop chain, often paired with Pilot (Pilot Flying J) . Offers fuel, parking, showers, and food.

FMCSA – The U.S. Federal Motor Carrier Safety Administration is a sub-agency within DOT that focuses specifically on commercial motor vehicles (CMVs). FMCSA creates and enforces the rules that truck drivers deal with daily, like Hours of Service, ELD requirements, CDL standards, and drug/alcohol testing.

FMCSA Regulations Book – A handbook containing Federal Motor Carrier Safety Regulations (FMCSR). CDL schools and companies require drivers to know these rules.

Fog Line – The solid white line on the right side of the road marking the edge of the lane. CDL tests often refer to it during straight-line backing.

Follow-Up Testing – After a driver completes the return-to-duty process, additional unannounced tests are required for up to 5 years. The frequency and duration are determined by the SAP.

Following Too Closely (Tailgating) – Driving too close behind another vehicle without enough stopping distance. For CDL drivers, this is a common violation that can be cited even without an accident occurring.

Fontaine Trailer Company – Specializes in flatbed, drop deck, and heavy-haul trailers. Fontaine is a common brand for specialized and oversized freight.

Forklift – A powered industrial vehicle used to load and unload freight at docks, warehouses, and receivers.

Forced Dispatch – When a company requires a driver to take a load, whether they want to or not.

Forty-Eight Foot (48 ft) Trailer – A standard trailer length commonly used in trucking, especially for regional and shorter-haul freight. While 53-foot trailers are more common today, 48-foot trailers are still widely used because they offer easier maneuverability in tight spaces such as city deliveries, docks, and older facilities.

Four Wheeler – Slang for passenger cars (anything with four wheels that isn’t a truck).

Frame – The main structural part of a truck or trailer to which all other components are attached. Must be inspected for cracks, bends, or weld issues.

Frayed Hose / Frayed Line – Damaged or worn air lines or electrical lines. Must be inspected during pre-trip and reported if defective.

Freeway – A type of highway designed for faster travel, with multiple lanes, higher speed limits, and no stoplights or intersections. Freeways are controlled-access roads, meaning vehicles enter and exit using ramps instead of cross streets.

Freight – The goods or cargo carried by a truck. Can be general freight, refrigerated (reefer), hazardous materials, or oversized.

Freight Bill – The invoice or paperwork showing charges for moving a shipment. Different from the Bill of Lading, which is the legal document of ownership.

Freight Broker – A middleman who arranges loads between shippers and carriers. Brokers don’t move freight themselves but handle logistics.

Freightliner – The largest heavy-duty truck brand in North America, owned by Daimler. Freightliners are widely used by major carriers for their fuel efficiency, availability of parts, and lower operating costs.

Freight Shaker (Slang) – CB slang for a Freightliner truck.

Freon – A refrigerant chemical (older types included R-12, newer systems use R-134a or R-1234yf) used in truck air conditioning systems. Leaks must be repaired immediately, as refrigerants are regulated for environmental safety.

Fuel Additive – A liquid chemical added to diesel fuel to improve performance or prevent problems. Common examples include anti-gel additives (to keep fuel from gelling in cold weather), cetane boosters (to improve combustion), and detergents (to clean injectors).

Fuel Anti-Gel – A specific type of fuel additive designed to keep diesel from thickening or “gelling” in freezing temperatures. Often sold at truck stops in winter.

Fuel Card – A payment card provided by a carrier or factoring company that drivers use to buy diesel at truck stops. Fuel cards often give drivers discounted fuel prices, track purchases, and sometimes cover other expenses like truck washes, scale fees, or repairs.

Fuel Island/Isle – The fueling area at a truck stop where drivers fill up with diesel. Usually includes windshield wash stations and DEF pumps.

Fuel Stop – A scheduled stop at a truck stop or terminal to refuel. Dispatch may assign specific fuel stops based on company fuel discounts or route planning.

Fuel Surcharge – An additional payment added to freight bills to help offset high fuel costs. Owner-operators often receive this on top of their base pay.

Fuel Tank – A metal tank that holds diesel fuel. Tanks must be secure, free of leaks, and have proper caps.

Fuel Tank Straps – Metal bands that secure the fuel tank to the frame. They must not be loose, broken, or missing.

Fueling – The process of filling the truck with diesel. Drivers are expected to follow company procedures, such as checking fuel type, logging gallons, and paying attention to reefer (trailer) fuel if hauling refrigerated freight.

Full Trailer – A term used in freight to describe a trailer that has no space left for additional cargo. Dispatch or shippers may ask if your trailer is “full” before assigning a partial (LTL) load.

Full Truckload (FTL) – A shipment that fills an entire trailer. Opposite of Less-than-Truckload (LTL).

Furniture Van – A type of moving trailer designed for transporting household goods (HHG). These trailers are taller and longer than standard dry vans, built to carry furniture, appliances, and boxed belongings during residential or commercial moves.

Fuse – A safety device in the electrical system that prevents overload by breaking the circuit.

Fuse Box/Panel – The panel where truck fuses are located. Checked if lights, wipers, or other systems fail.

Garmin – A leading brand of GPS units designed for truckers. Truck-specific Garmin GPS devices account for truck routes, bridge heights, and restrictions.

Gauges – Instruments on the dash cluster that monitor vital systems like oil pressure, coolant temperature, air pressure, and fuel levels.

Gearbox – Another term for a truck’s transmission. It houses the gears and mechanisms that transfer power from the engine to the drive wheels. In trucking, gearboxes may be manual (with 9, 10, 13, or 18 speeds) or automatic. Proper shifting is critical to protect the gearbox from damage.

Gear Ratio – The relationship between the number of turns of the engine (input) and the number of turns of the wheels (output). In trucking, gear ratios affect pulling power and fuel efficiency. Lower ratios (like 3.25) give better fuel economy, while higher ratios (like 3.90) provide more torque for heavy loads or steep grades.

Gear Shifter – The lever used to manually change gears in a truck’s transmission. In big rigs, the shifter is often tall and may have switches (range selector or splitter) to access multiple gear ranges, allowing a 9-, 10-, 13-, or 18-speed transmission to function. Proper use of the shifter, along with clutch control, is a key CDL skill.

General Knowledge – Covers basic safe driving principles, vehicle inspection, shifting, space management, hazard awareness, and accident procedures. This is the foundation for all CDL drivers.

General Knowledge Test – A required written exam for all CDL applicants. Covers basic trucking rules, vehicle operation, safety regulations, and driver responsibilities. Must be passed to get a CDL permit.

Glad Hands – A slang term for the flat-shaped connectors that link the tractor’s air lines to the trailer. When the two ends “clap” together, they form a secure seal. Sometimes called [Air Couplers].

G.O.A.L. (Get Out And Look) – A safety rule drilled into drivers during CDL training and on the job. It means that if you’re unsure about clearance, blind spots, or while backing, stop the truck, get out, and physically check before moving again.

Governor (Speed Governor) – A device that limits the maximum speed of a truck. Many company trucks are “governed” at 62–68 mph to improve fuel efficiency and safety.

GPS (Global Positioning System) – A navigation system used to plan routes, avoid restricted roads, and find truck stops. Truck-specific GPS is preferred over phone apps.

Grade (Incline/Decline, Mountain Grade) – The steepness of a road, usually measured as a percentage. A 6% grade means the road rises (or falls) 6 feet for every 100 feet of distance. In trucking, “grade” often refers to mountain upgrades (climbs) or downgrades (descents).

Grain Trailer (Hopper Trailer) – A bulk commodity trailer used for transporting grain, corn, soybeans, or similar products, usually with bottom hoppers for unloading.

Grease (Truck Lubricant) – A thick, heavy lubricant used on trucks to reduce friction and wear on moving parts. The most common application is fifth wheel grease, which allows smooth pivoting between the tractor and trailer. Grease is also used on chassis fittings, suspension joints, and other components that require regular lubrication. Proper greasing prevents metal-on-metal damage and is a key part of routine truck maintenance.

Great Dane Trailers – A major U.S. trailer manufacturer that produces dry vans, refrigerated trailers, and flatbeds. Known for durability and long service life, Great Dane trailers are common in national carrier fleets.

Grinding Gears – The loud grinding noise that happens when a driver tries to shift a manual transmission without matching engine RPM to the correct gear speed. Common when learning to double-clutch or float gears. Frequent gear grinding can damage the transmission.

Gross Combination Weight Rating (GCWR) – The maximum legal combined weight of the tractor, trailer, cargo, and everything else when hooked together.

Gross Vehicle Weight (GVW) – The total weight of a vehicle and its load, including truck, trailer, cargo, fuel, and driver.

Gross Vehicle Weight Rating (GVWR) – The maximum legal weight of a single vehicle, as set by the manufacturer. Exceeding this is illegal and unsafe.

Gross Weight – The total weight of the truck, trailer, cargo, fuel, and driver as measured on a scale. This is the number used to ensure the load is within legal weight limits.

Gravel Hauler – A dump truck or end dump trailer designed to haul gravel and similar materials, common in construction zones.

Ground Clearance – The distance between the lowest part of the truck (often the differential or frame) and the ground. Important for avoiding damage on uneven roads.

Group Run – A group of trucks from the same company or multiple drivers running together. Similar to a convoy but sometimes used in dispatch language.

Hammer Lane – Slang for the far-left lane of a highway, typically the fastest lane. Many states restrict trucks from using the hammer lane.

Hand Truck – A small two-wheeled dolly used to move boxes or freight at shippers and receivers. Local and LTL drivers often use these for store deliveries.

Hazard Lights (Flashers) – The blinking lights used to warn other drivers when a truck is stopped on the shoulder, moving slowly, or in an emergency.

Hazardous Conditions – A term used in logs and safety briefings to describe weather or road conditions that may require reduced speed or extra caution.

Hazmat (Hazardous Materials) – Dangerous goods such as chemicals, fuels, or explosives. Hauling hazmat requires a special CDL endorsement (H) and extra safety training.

Hazmat Endorsement (H) – A CDL add-on that allows drivers to haul hazardous materials. Requires a background check, fingerprinting, and a written test.

Hazmat Route – A highway or road specifically designated (or restricted) for trucks carrying hazardous materials. Some routes require hazmat drivers to follow them, while others ban hazmat altogether in tunnels, bridges, or city areas. Drivers must always follow hazmat routing signs and state/local regulations to avoid fines or safety risks.

Hazmat Placards – Diamond-shaped signs placed on trailers carrying hazardous materials to identify the type of cargo (flammable, corrosive, explosive, etc.).

Headache Rack – A protective metal barrier mounted behind the cab, often on flatbeds, to stop cargo from shifting forward and hitting the cab.

Headlights – The front lights of a truck, required to be inspected before every trip and used whenever visibility is poor.

Headset – Bluetooth headsets, like BlueParrott and Blue Tiger, used by truckers for hands-free calls and communication. Required by law for safety.

Heavy Highway Use Tax (HHUT / HVUT) – An annual federal tax (Form 2290) required for trucks weighing 55,000 pounds or more. Once paid by the company, drivers must keep a stamped Schedule 1 in the cab as proof of payment. This document is often checked during DOT inspections and is required for registration renewals.

High Beams – Bright headlights for nighttime driving. Must be dimmed when approaching traffic.

High Cube Trailer – A trailer with extra interior height, often used in intermodal and specialized freight.

High Side / High-Sided – When a vehicle gets stuck on a raised surface because its frame is resting on the ground, usually at railroad crossings or steep approaches.

High Theft Area – A region or location known for frequent cargo theft, such as certain truck stops, rest areas, or urban zones. Drivers hauling valuable freight are often instructed to avoid parking in these areas or to follow special security rules, like not stopping within the first 200 miles after pickup.

High Value Load (HVL) – A shipment carrying cargo worth $100,000 or more, such as electronics, pharmaceuticals, alcohol, or luxury goods. Because of the high risk of theft, carriers place strict rules on HVLs: team driving, limited stops, frequent check-ins with dispatch, and parking only in approved locations.

Highway – A public road that connects cities, towns, and states. Highways can include interstates, U.S. routes, and state highways. In trucking, “highway miles” usually means long-distance travel on major roads.

Highway Hypnosis – A trance-like state drivers may fall into after long hours on the road, where they lose focus and awareness.

Highway Patrol – State-level law enforcement officers who monitor highways for safety, speed, and trucking compliance.

Highway Use Tax (HUT) – A tax required by certain states (like New York) for trucks operating on their highways.

Hiring Area – The geographic region from which a trucking company hires drivers. Not all companies hire in every state.

Hood Mirror – Mirrors mounted on the truck hood that help drivers see blind spots directly in front of and alongside the cab.

Hook (Drop & Hook) – The process of connecting a tractor to a trailer. In drop-and-hook situations, a driver drops off one trailer and then “hooks” to another, instead of waiting for live loading or unloading. This saves time and is common at large carriers, terminals, and big shippers.

Horsepower (HP) – A measurement of an engine’s power, showing how much work it can do over time. In trucking, horsepower affects how quickly a truck can accelerate, climb hills, and handle heavy loads. Most modern highway tractors have between 400 and 600 horsepower. Higher horsepower can make pulling heavy freight easier but may also increase fuel consumption if not managed efficiently.

Hours of Service (HOS) – A set of federal regulations created by the FMCSA that control how many hours truck drivers can drive and work before they must take a break. The goal is to prevent fatigue and improve safety on the road. HOS rules include limits on driving time, on-duty time, and required off-duty rest periods.

Hours of Service Violation – Occurs when a driver falsifies log entries, drives beyond legal hours, or fails to use an ELD (Electronic Logging Device). These violations are heavily enforced and can result in out-of-service orders.

Household Goods (HHG) Miles – A mileage calculation method based on an old atlas system used for moving companies. Some carriers still use HHG miles to figure pay. It’s usually shorter than actual driven miles, meaning drivers may earn less than expected.

Hot Load – A load that must be delivered quickly or has a high priority. Dispatch may push drivers to move these loads faster.

Hot Shot Trucking – A type of trucking using pickups or smaller trucks with flatbed trailers to haul urgent or smaller loads. Popular with owner-operators.

HOV Lane (High-Occupancy Vehicle Lane) – A special lane reserved for vehicles with multiple passengers, often on urban highways. Trucks are usually restricted from using HOV lanes unless specifically allowed by state law.

Hub – A central location in a freight network where loads are consolidated, transferred, or routed to their final destinations.

Hub Drum (Brake Drum) – The heavy metal drum attached to the wheel hub that works with brake shoes to slow the truck. When the brakes are applied, the shoes press against the inside of the drum, creating friction to stop the wheel.

Hub Miles – The actual miles driven as measured by the truck’s hub odometer, not just the shortest route.

Hub Oil – The lubricating oil inside a wheel hub that keeps the wheel bearings cool and running smoothly. Drivers must regularly check hub oil levels (often through a clear sight cap) during pre-trip inspections. Low or leaking hub oil can lead to wheel seal failure or wheel lockup.

Hydraulic Brakes – A braking system that uses fluid pressure instead of air. Found on smaller commercial vehicles under 26,000 lbs.

Hydraulic Fluid – A specialized oil used in hydraulic systems, such as power steering, liftgates, or heavy equipment attachments. Must be kept clean and at the right level to avoid system failure.

Hydroplaning – When tires lose contact with the road surface on wet pavement, causing a loss of control.

Hyundai Translead – A trailer manufacturer producing dry vans, refrigerated trailers, and chassis. Hyundai trailers are widely used in intermodal and long-haul trucking in North America.

Idle / Idling – When a truck engine is running but the vehicle isn’t moving. Often restricted by company policies or local anti-idling laws.

Idle Reduction System (APU / Bunk Heater) – Equipment that reduces the need to idle by providing heat, cooling, or electricity for the cab. Helps save fuel and meet emissions laws.

IFTA (International Fuel Tax Agreement) – An agreement between U.S. states and Canadian provinces that simplifies fuel tax reporting for trucks operating across borders. Drivers carry an IFTA license and display IFTA decals on their truck.

IFTA Decal – Stickers placed on both sides of the truck showing that the carrier is registered under IFTA. Must be renewed yearly.

Improper Lane Change – A moving violation issued when a driver changes lanes without signaling, without clearance, or in a manner unsafe for surrounding traffic. CMVs are closely watched for this due to blind spots.

In Cab Inspection – Part of the CDL skills test where drivers check safety equipment inside the cab, including gauges, wipers, horns, lights, defroster, and emergency equipment.

In Time – The time a driver checks in or arrives at a shipper or receiver for a load or delivery. Dispatch and brokers use in times to track schedule compliance, detention pay, and billing.

In Transit – A shipping term meaning freight is currently being transported between pickup and delivery.

Incident – A minor event such as damage to property or equipment that doesn’t meet the threshold of a DOT-recordable accident. Still reported to the company and sometimes appears on a DAC report.

Independent Contractor (Owner-Operator) – A driver who owns their truck and operates under their own authority or leases onto a carrier. Responsible for expenses, taxes, and profits.

Ingress/Egress – Terms used in safety training to describe safe entry (ingress) and exit (egress) from the cab, trailer, or worksite.

Inspection (DOT Inspection) – Safety checks performed on trucks at weigh stations, roadside, or company yards. Levels range from basic walk-arounds (Level 3) to full inspections (Level 1).

Inspection Report (Driver Vehicle Inspection Report – DVIR) – A required form where drivers note defects found during pre-trip or post-trip inspections. Must be kept in the truck.

Insurance Certificate – Proof of insurance coverage for the truck. Carriers are required to keep it in the permit book and provide it during inspections.

Insurance Claim – A formal request made to an insurance company after an accident, cargo damage, or other loss. In trucking, claims may involve liability (damage to others), cargo (freight loss or damage), or physical damage (to the truck/trailer). The carrier usually handles the claim, but drivers may need to provide accident reports, photos, or statements.

Interaxle Differential Lock (Power Divider Lock) – A switch in the cab that locks the drive axles together for traction in slippery conditions. Commonly called the “diff lock.”

Intermodal – Freight that moves in containers which can be transferred between trucks, trains, and ships. Common around ports and rail yards.

International Trucks – A major U.S. truck manufacturer (part of Navistar). Known for models like the International LT and ProStar, which are widely used by fleets and training schools.

Interstate Commerce – When a driver or carrier hauls freight across state lines or crosses the border into another country (Canada or Mexico). This type of trucking requires federal operating authority from the FMCSA, including a USDOT number and often an MC (Motor Carrier) number. Interstate drivers must follow federal regulations such as Hours of Service (HOS), electronic logging device (ELD) rules, and weight restrictions. Example: A load that starts in Texas and delivers in Georgia.

Interstate Excepted (EI) – A type of self-certification for drivers who operate across state lines but in jobs that are federally exempt from medical card requirements. Examples include government workers, firefighters, emergency response drivers, and farm equipment transporters. These drivers do not need to keep a Medical Examiner’s Certificate (MEC).

Interstate Non-Excepted (NI) – A type of self-certification for drivers who operate across state lines (interstate commerce) and are required to follow full federal medical rules. Most over-the-road, regional, and company drivers fall into this category. Drivers must carry and maintain a valid Medical Examiner’s Certificate (MEC).

Intrastate Commerce – When a driver or carrier hauls freight only within a single state and never crosses state lines. Intrastate trucking requires state-level authority (permits or registration through that state’s DOT), but not federal interstate authority. Rules may vary by state, but most still require compliance with basic safety, medical card, and hours-of-service standards. Example: A load that picks up and delivers only in Florida.

Intrastate Excepted (EA) – A type of self-certification for drivers who operate only within one state and in jobs that are exempt from medical card requirements. Examples include some local government drivers, school bus drivers under certain programs, or farm-related work. These drivers do not need to carry a Medical Examiner’s Certificate (MEC).

Intrastate Non-Excepted (NA) – A type of self-certification for drivers who operate only within a single state (intrastate commerce) and are required to follow that state’s medical card rules. These drivers must carry and maintain a valid Medical Examiner’s Certificate (MEC).

Inverter (Power Inverter) – A device that converts the truck’s DC battery power into AC power, allowing drivers to run household electronics (microwaves, laptops, etc.) inside the cab.

Invoice – A bill for services or freight delivered. In trucking, carriers issue invoices to shippers or brokers to get paid.

Jackknife – When a tractor and trailer fold toward each other at a sharp angle, usually caused by braking too hard or losing traction. Considered a dangerous accident.

Jake Brake (Engine Brake) – A braking system that uses engine compression to slow the truck, saving wear on service brakes. Often restricted in towns due to noise ordinances.

Jam Up – Slang for a traffic jam, often used on the CB.

Jaguar (Slang) – CB slang for a fast-moving four-wheeler weaving through traffic.

Jifflox (Converter Dolly) – A wheeled device with a fifth wheel used to connect one trailer to another in doubles or triples.

JIT (Just-in-Time) Loads – Freight that must be delivered at a very specific time to keep a supply chain running smoothly. Common in auto plants, food distribution, and retail. These loads are extremely time-sensitive, with little or no room for delays. Being late can shut down production lines or cause major penalties.

Jobber – A middleman company that buys fuel or freight space and resells it to carriers or customers.

Joint – Slang for a truck stop or rest area (example: “Pulling into the joint up ahead”).

Joint and Several Liability – A legal term in trucking accidents meaning multiple parties (carrier, shipper, broker) can be held liable for damages.

Journal – Refers to the part of an axle where the bearing sits, or in some companies, a term for driver’s daily logs (old-school use before ELDs).

Joy Stick (Control Lever) – A control stick or lever used in some trucks for transmissions or auxiliary equipment.

Jump Seat – The passenger seat in a truck, sometimes used by trainees or riders.

Jump Start – Starting a truck with a dead battery using another vehicle’s power or a jump box.

Junkyard Dog (Slang) – CB slang for a tough or aggressive driver, or sometimes for a beat-up truck.

Junction – A highway intersection where multiple routes meet, often referenced by dispatch or GPS.

Jurisdiction – An area (such as a state or province) that collects fuel taxes under IFTA. Carriers must report miles driven in each jurisdiction.

Kenworth – A U.S. truck brand often seen as a premium choice for long-haul drivers. Kenworths are known for high build quality, comfortable interiors, and aerodynamic designs.

Key On/Key Off Test – Part of the CDL air brake pre-trip. Drivers cycle the ignition to check warning lights, buzzers, and gauges.

Kick Plate – A protective plate (often metal or rubber) installed at the base of a wall, door, or truck interior to prevent damage from impacts, cargo, or boots. In trucking, it can also refer to reinforced protection inside trailers to reduce freight damage.

Kilogram (Unit of Weight) – A metric unit of weight equal to 2.2 pounds. While trucking in the U.S. mainly uses pounds, many shippers, scales, and freight documents (like bills of lading) may list weights in kilograms. Drivers often need to convert kilograms to pounds to confirm they are within legal weight limits.

Kilometer (Unit of Distance) – A metric unit of distance. One kilometer equals 0.62 miles. Canadian road signs and some cross-border freight documents use kilometers instead of miles.

Kingpin – The large steel pin under the front of a trailer that locks into the tractor’s fifth wheel to connect the two. CDL pre-trip inspections require checking the kingpin and locking jaws for wear or damage.

 Kingpin Lock – A security device that attaches over the kingpin to prevent unauthorized movement of the trailer. Commonly used when trailers are dropped in unsecured yards.

Kingpin-to-Axle (KTA) Measurement – The distance between the kingpin and trailer axles. Important for weight distribution and compliance with bridge laws.

Kingpin-to-Rear-Axle (KPRA) Measurement – The distance between the trailer’s kingpin and the center of the rearmost axle group (usually the tandems). Many states, especially California, regulate this measurement. If the KPRA distance exceeds the legal limit (commonly 40 feet in California), drivers must adjust the tandem position to comply.

Knock the Brakes Off (Slang) – A phrase used when releasing the spring brakes before moving the truck.

Knuckle-Boom Crane – A folding hydraulic crane sometimes mounted on trucks or trailers for loading heavy equipment or materials.

Knowledge Test (CDL Written Test) – The written test drivers must pass to earn their CDL permit and endorsements.

KYU Number (Kentucky Weight Distance Tax) – A tax number required for trucks over 59,999 lbs operating in Kentucky. Must be kept in the permit book.

Landing Gear – The retractable legs on the front of a trailer used to support it when it’s not connected to a tractor. Must be raised and lowered properly during drop-and-hook.

Lane – The route or corridor a driver regularly runs freight in (example: “I run the Midwest lane”).

Lane Restriction – A rule limiting trucks to certain lanes on highways (usually the right two lanes). Common in states with heavy traffic.

Lane Line (White Line) – The dashed white line painted on the road to separate lanes of traffic moving in the same direction. In the U.S., each painted stripe is typically 10 feet long with a 30-foot gap before the next one. Truckers use lane lines as guides for staying centered in their lane, especially at night or in heavy traffic.

Landing Pad – A small, reinforced concrete strip or pad where trailers are dropped. It prevents trailer landing gear from sinking into soft ground like dirt or gravel.

Lanternfly (Spotted Lanternfly) – An invasive insect that damages crops and trees. Truck drivers traveling through certain states (such as Pennsylvania and surrounding areas) are required to carry a Spotted Lanternfly Permit and inspect their trucks and trailers to prevent spreading the pest. Fines can be issued if inspections are skipped or the permit is missing.

Layover – When a driver has to wait (often overnight) for a new load or for freight to be ready. Some companies pay “layover pay” for this downtime.

Late Appointment Fee – A penalty charged by shippers or receivers if a driver misses their scheduled delivery or pickup appointment time. Can reduce driver pay if deducted from settlement.

Lease Operator – A driver who leases a truck from a carrier but operates as an independent contractor. Different from a company driver or owner-operator.

Lease Purchase – A program where a driver leases a truck from a carrier with the option to buy it at the end. Popular but often risky for rookies.

Leave Yourself an Out (See Also: Smith System Rule) – A defensive driving principle that teaches drivers to always maintain an escape route in case of sudden stops, swerves, or hazards. Part of the Smith System’s five key rules.

Left-Lane Law – State laws that restrict trucks from using the far-left lane on highways.

Legal Weight – The maximum weight allowed by law on a truck or axle. Determined by federal and state bridge laws.

Less-Than-Truckload (LTL) – A shipment that doesn’t fill a full trailer. Multiple LTL loads are combined into one trailer. Opposite of Full Truckload (FTL).

Liability Insurance (Trucking) – Protects against damage or injury caused by a commercial truck in an accident. FMCSA sets the minimum at $750,000, but most carriers carry $1,000,000+ to meet shipper and broker requirements.

Lift Axle – An axle that can be raised or lowered on a truck or trailer to help with weight distribution.

Lifted Axle – Another term for a lift axle (used when the axle is raised off the ground to save fuel or wear).

Lift Gate – A hydraulic platform on the back of a truck or trailer used to raise and lower freight for deliveries where no dock is available.

Line 1 – Off-Duty – Time when the driver is not working and free of all responsibility for the truck. Examples: at home, resting at a truck stop, or off-shift.

Line 2 – Sleeper Berth – Time spent resting in the truck’s sleeper compartment. This counts toward required rest breaks and 10-hour resets.

Line 3 – Driving – Time when the driver is physically operating the truck on the road. Must be recorded accurately when the truck is in motion.

Line 4 – On-Duty, Not Driving – Time spent working but not driving. Includes pre-trip inspections, fueling, waiting at docks, or handling freight.

Linehaul – The long-distance movement of freight between terminals. Common term in LTL and parcel industries.

Liquid Surge – The forward and backward movement of liquid inside a tanker when the truck accelerates, brakes, or turns. Surge can cause the truck to feel like it’s being pushed or pulled, especially when stopping. Drivers are trained to brake and accelerate smoothly to control it.

Live-Bottom Trailer – A specialized trailer with a moving conveyor belt floor that pushes freight out the back instead of lifting like a dump trailer.

Live Load / Live Unload – When a driver waits while the trailer is loaded or unloaded. This can take anywhere from minutes to several hours depending on the shipper or receiver. Live unloads are common in grocery and retail distribution centers and may result in detention pay if they exceed the agreed waiting time. Opposite of drop-and-hook.

Livestock Trailer – A trailer with ventilation and specialized flooring used for hauling animals like cattle, pigs, or sheep.

Load – General term for freight being hauled. Also used as a dispatch term (“I’ve got a load for you”).

Load Bar / Load Lock – An adjustable metal bar or locking device used inside trailers to keep freight from shifting during transport. Often required by shippers for certain types of loads.

Load Board – An online system where brokers and carriers post and search for available freight. Common for owner-operators.

Load Lock – A bar used inside trailers to secure freight and prevent shifting.

Load Number – A unique number assigned by a carrier, shipper, or broker to identify a specific load. Used for communication with dispatch, billing, and tracking freight.

Load Shift – When cargo moves inside the trailer, often due to poor securement. Dangerous and can cause rollover accidents.

Loaded Miles – The miles a truck drives while carrying freight. These are the miles that usually generate revenue for both the driver and the carrier.

Local Haul – A type of trucking run where freight is moved only within a small geographic area, usually within the same city or surrounding counties. Local hauls are short-distance trips, often under 100 miles, and may involve multiple stops in a day.

Local Job – A trucking position where the driver runs within a small geographic area, usually returning home every night. Local jobs often involve city driving, multiple stops, and more manual labor (like unloading).

Locking Jaws – The mechanism inside the fifth wheel that locks around the kingpin. CDL pre-trip requires checking they’re secure.

Log Audit – A review by a carrier or DOT officer to ensure driver logs (ELDs or paper) are accurate and compliant.

Logbook (ELD / Paper Logs) – The record of a driver’s hours of service (HOS). Today most are electronic (ELDs), but the term “logbook” is still used.

Long-Form Medical Card – The complete medical examination report a DOT-certified doctor fills out during a driver’s physical. It lists the driver’s health history, exam results, and medical examiner’s findings. This form must be kept on file by the driver and their carrier.

Long-Haul (Over-the-Road / OTR) – Long-distance trucking, often coast-to-coast or multi-day trips.

Love’s – A major national chain of travel centers offering fuel, parking, food, showers, maintenance, and convenience stores. Known for its Love’s Fuel Card and tire and maintenance services.

Love’s Fuel Card – Fuel cards issued by Love’s Travel Stops. Provide discounts and tracking for fleets fueling at Love’s.

Low Air Warning – A warning light, buzzer, or alarm that activates when system air pressure drops too low (usually around 60 PSI). Alerts the driver to stop and fix the problem before spring brakes apply automatically.

Low Clearance – A bridge or structure that may be too low for a truck or trailer to pass under. Often marked with signs.

Lowboy Trailer – A type of flatbed trailer with a very low deck height, used to haul heavy equipment or oversized loads.

Lumbar Support – A feature in many truck seats that provides extra support to the lower back (lumbar region of the spine). It often uses an inflatable air bladder or adjustable cushion that the driver can pump up or release to fit their comfort. Proper lumbar support helps reduce back pain, fatigue, and long-term strain during long hours of driving.

Lumper – A worker at a warehouse or distribution center who loads or unloads trailers for a fee. Many grocery warehouses use lumpers. Drivers are often required to pay upfront and then get reimbursed by their company or broker.

Lumper Fee – The payment charged by a lumper service for loading or unloading a trailer at a warehouse or distribution center. Some companies reimburse drivers, while others require brokers or shippers to cover the cost. Drivers must always get a receipt for lumper fees.

Mack Trucks (MAC) – An American truck brand recognized for toughness and heavy-duty performance. Mack trucks are widely used in construction, vocational, and highway applications.

Maintenance – Regular service and repair work done on trucks and trailers to keep them safe and compliant. Includes oil changes, brake checks, and inspections.

Maintenance Bay – A service area at a terminal or shop where trucks and trailers are inspected and repaired.

Maintenance Log – A record drivers or carriers keep of all truck and trailer maintenance. Can be paper or electronic. Often reviewed during inspections.

Mandatory Rest Break – The FMCSA-required 30-minute break drivers must take after 8 hours of driving.

Major Violation – A serious traffic or safety violation, such as DUI, reckless driving, or driving without a CDL. These can disqualify a driver.

Manifest – A document that lists the cargo being hauled, including description, weight, origin, and destination.

Manifest Number – A unique number assigned to a shipping manifest. Used for tracking loads and paperwork.

Manual (Transmission) – A truck transmission that requires the driver to shift gears manually using a clutch and gear shifter. Common setups include 9-, 10-, 13-, and 18-speed gearboxes. Driving a manual requires learning double-clutching or floating gears. If a driver tests in an automatic, their CDL will carry a restriction (E) preventing them from driving manual trucks.

Marker Lights – Small lights mounted on the front, sides, and top of a truck or trailer that outline its size and shape at night or in poor visibility. Required by law for safety and checked during inspections. Sometimes called clearance lights or identification lights depending on their placement.

Max Height – The maximum legal height for trucks and trailers on U.S. highways. In most states it’s 13 feet 6 inches, though some states allow up to 14 feet. Drivers must always watch for low clearance signs and know their vehicle’s exact height to avoid bridge strikes.

Max Weight – The maximum weight allowed by law for a truck and trailer combination, usually 80,000 lbs gross unless special permits are issued.

Medical Examiner’s Certificate (MEC/Medical Card) – The official certificate issued by a DOT-certified medical examiner after a driver passes their DOT physical. This is the document drivers must carry as proof of being medically qualified to drive. Often referred to as the “short-form” medical card.

Mega Carrier – A very large trucking company with thousands of trucks and nationwide operations (examples: Swift, Werner, Schneider). Known for hiring and training new drivers.

Merging Lane – A lane on a highway where vehicles enter traffic. CDL tests emphasize safe merging techniques.

Mentor Driver – A driver with more experience who provides ongoing guidance and support to rookie drivers. Unlike trainers, mentors are not always in the truck but serve as resources for advice, problem-solving, and career development within a company.

Messenger Load – A small or partial shipment carried along with a larger load, often handled like an add-on.

Metric Ton (MT) – A unit of weight equal to 1,000 kilograms (2,204 pounds). Sometimes used in shipping documents.

Mid-Roof Sleeper – A truck cab with a sleeper compartment that has a medium-height roof, taller than a flat top but shorter than a condo sleeper.

Mile Marker – A numbered sign placed along highways, usually every mile, that shows the distance from the start of the highway within a state. Mile markers run in ascending or descending order depending on the direction of travel (east–west highways generally increase from west to east, and north–south highways from south to north). They are used by drivers, dispatchers, and emergency responders to pinpoint exact locations. For truckers, mile markers are important for giving directions, reporting breakdowns, and tracking progress on long routes.

Mileage Pay – A pay method for company drivers, based on miles driven (practical miles, hub miles, or household goods miles).

Mileage Tax – A tax charged by some states based on miles driven within that state. Examples: Oregon and Kentucky.

Milk Run – A route that makes multiple pickups or deliveries in a loop, like delivering to several stores on one trip.

Million Miler – A driver recognized by a company for driving one million accident-free miles.

Minor Violation – A less serious traffic or safety offense that goes on a driver’s record but usually carries lighter penalties than a major violation. Examples include a broken light, expired registration, or slightly over the speed limit. Too many minor violations can still hurt a driver’s CSA score and employment record.

Minimum Following Distance – The minimum space a truck must leave between itself and the vehicle ahead. Typically 1 second for every 10 feet of vehicle length (under 40 mph), more at higher speeds.

Missed Appointment – When a driver does not arrive at a shipper or receiver at the scheduled time, which can result in fines or rescheduling delays.

Mirror Check – The constant scanning of mirrors while driving or backing. A key part of defensive driving.

Money Code – A unique code issued by companies like EFS or Comdata that allows drivers to access funds on the road. Often used to pay for lumper services, repairs, or to give drivers a cash advance. The driver provides the money code at a truck stop or service desk to receive payment or apply it toward expenses.

Monthly Maintenance Report – A report carriers may require drivers to submit, logging inspections, repairs, and truck condition.

Motor Carrier – A company authorized by the DOT/FMSCA to transport goods for hire.

Motor Carrier Number (MC Number) – A number issued by the FMCSA for carriers that operate interstate. Required for hauling freight across state lines (unless exempt).

Motor Locked – A condition where the engine is seized or stuck, often from mechanical failure or lack of oil.

Motor Vehicle Record (MVR) – A driver’s official driving history, checked by carriers and insurance companies.

Mounted and Secure – A common phrase used during the CDL pre-trip inspection to confirm that parts are attached firmly and not damaged.

Moving Violation – A traffic offense committed while driving a truck, such as speeding, improper lane change, or running a red light.

MT (Empty) – A common abbreviation in trucking meaning “empty trailer.” Used by dispatch when assigning loads.

Muffler – A truck exhaust system component that reduces noise. Trucks with modified mufflers are often louder, sometimes called “straight pipes.”

Multi-Axle Trailer – A trailer with more than two axles, designed for heavy or specialized loads.

Multi-Stop Load – A load that has more than one pickup or delivery location. Can increase pay but also adds time.

Municipal Haul – Freight or work done for city or local governments, such as hauling waste, gravel, or equipment.

National Network – A system of highways designated by the federal government for trucks. These roads are built to handle large commercial vehicles and are often the preferred routes for truckers.

Negative Report – A term used in compliance or safety reporting when no violations or incidents occurred (example: a negative drug/alcohol test report).

Net Weight – The weight of the cargo alone, not including the truck, trailer, or packaging.

Neutral – Gear position in which the transmission is disengaged. Important in shifting and CDL road tests.

New Entrant Audit – A safety audit all new motor carriers must pass within their first 18 months of operation.

NHTSA – The National Highway Traffic Safety Administration is a Federal agency that regulates vehicle safety standards, recalls, and crash testing.

Night Driving – Driving at night, which poses increased risks due to reduced visibility, fatigue, and impaired motorists. Often part of rookie orientation.

No Parking Zone – An area where trucks are prohibited from stopping or parking. Violations can result in fines or towing.

No Zone – The blind spots around a truck where cars disappear from the driver’s view (sides, rear, and directly in front).

No-Idle Zone – A designated area (often at warehouses or cities) where trucks must turn off engines to reduce pollution and noise.

Non-CDL Vehicle – A commercial-type vehicle under 26,001 lbs GVWR that doesn’t require a CDL.

Non-Driving Time – Hours logged as off-duty, sleeper berth, or on-duty not driving. Used in HOS tracking.

Non-Forced Dispatch – When a driver has the option to turn down loads rather than being required to accept them.

Nose Cone (Aero Device) – A plastic or fiberglass fairing mounted on the front of a trailer to improve aerodynamics and fuel efficiency.

NTSB (National Transportation Safety Board) – Federal agency that investigates crashes, including major trucking accidents.

NVOCC (Non-Vessel Operating Common Carrier) – A freight forwarder that organizes shipments without owning vessels or trucks.

Nose of Trailer – The very front section of a trailer, located just behind the tractor. It’s the front inside wall of the trailer where freight is loaded first and often secured against. On the outside, the nose includes the trailer’s front wall and sometimes the landing gear area.

Off Duty Time – Hours when a driver is relieved of all work responsibilities. Recorded in the logbook as Line 1.

Off Ramp – A lane that allows vehicles to exit a highway. Important for route planning and safe speed management.

Off-Road Diesel – A type of diesel fuel dyed red to show it is not taxed for highway use. It is meant for equipment such as tractors, construction machinery, and generators. Using off-road diesel in a commercial truck on public highways is illegal and can result in heavy fines if discovered during an inspection.

Oil (Engine Oil) – Lubricates engine components, reduces friction, and helps carry away heat. Trucks typically use diesel-specific motor oils (15W-40 is common). Oil levels must be checked daily with the dipstick.

Oil Additive – A product mixed with engine oil to improve lubrication, reduce wear, or prevent breakdown under extreme conditions. Some drivers use oil stabilizers or friction reducers to extend engine life, though opinions on effectiveness vary.

On Duty Time – Hours that a driver is working but not necessarily driving (fueling, loading, inspections, etc.). Recorded in the logbook as Line 4.

On Ramp – A lane that allows trucks and cars to enter a highway. CDL tests emphasize safe merging from on-ramps.

OOIDA (Owner-Operator Independent Drivers Association) – A national trade organization that represents professional truck drivers, including owner-operators and small fleets. OOIDA provides advocacy, legal help, insurance programs, and business resources for truckers.

Operating Authority – Legal permission granted by the FMCSA that allows a motor carrier to transport freight for hire. A carrier must have an MC number (Motor Carrier number) and proper insurance on file. Without operating authority, a trucking company cannot legally haul freight across state lines unless exempt.

Orientation – The training and onboarding period when a new driver joins a company. Covers company policies, safety procedures, and paperwork.

Origin – The location where a shipment begins. Listed on the bill of lading, it’s the point where the driver picks up the load before transporting it to the destination.

OS&D (Overages, Shortages, and Damages) – A common term in freight for reporting issues with a load. (Overage = More product than ordered. Shortage = Less product than ordered. Damage = Freight that is broken, spoiled, or unusable.) Drivers must report OS&D issues immediately to dispatch or the broker.

Out of Pocket Expense – A cost a driver or owner-operator must pay directly (like tolls, lumper fees, or roadside repairs) before possible reimbursement.

Out of Route – A general term used in trucking when a driver goes off the planned or authorized route. This could be intentional (detours, personal use, rest stops) or unintentional (missed exits, wrong turns).

Out of Route Miles – The extra miles a driver racks up when going off the planned route. Carriers and dispatchers track these closely because they affect fuel costs, scheduling, and pay.

Out of Service – A status given by DOT officers when a truck or driver has a serious violation. The truck or driver cannot operate until the issue is corrected.

Out of Service Violation – A serious safety issue found during an inspection that requires a truck, trailer, or driver to stop operating until the problem is fixed. Examples include bad brakes, flat tires, logbook falsification, or driving without a valid CDL. Being placed “out of service” means the vehicle cannot move legally until repairs are made or the violation is corrected.

Out Time – The time a driver finishes unloading at a receiver and is officially released. Dispatchers and brokers use out times to track when a driver is available for the next load and for billing detention or unloading times.

Outage – The empty space left in a tanker to allow for liquid expansion. Tankers are never filled to the very top to prevent overflow.

Outgate – The process of leaving a shipping yard, terminal, or port with a load after paperwork and inspections are completed.

Outside Carrier – A carrier contracted by a broker or shipper instead of being the primary assigned carrier.

Outsourcing – When a trucking company hires outside carriers or contractors to haul freight instead of using company drivers.

Over Dimensional Load / Oversize Load – Freight that exceeds legal height, width, or length limits and requires special permits and signage.

Over the Road (OTR) – Long-haul trucking that involves multi-day or cross-country runs. Drivers often spend weeks away from home.

Overdrive – A gear ratio in which the transmission output turns faster than the engine input, improving fuel efficiency at highway speeds.

Overhead Clearance – The vertical space under bridges, signs, or structures. Trucks must always know their height to avoid collisions.

Overnight Parking – Parking at truck stops, rest areas, or safe locations for required rest breaks. Some shippers/receivers also allow overnight parking on-site.

Oversize Load – A load that exceeds the legal size limits set by federal or state law. This can mean extra width, height, or length beyond what’s normally allowed. Oversize loads require special permits, and in many cases, escort vehicles (pilot cars) to guide the truck. Bright yellow “Oversize Load” banners, lights, and sometimes flags must be displayed.

Overspeed – Driving a truck faster than the set governor or manufacturer’s limits. Often flagged by telematics systems.

Overturn – A rollover accident where a truck tips onto its side or roof. Often linked to speed on curves, load shift, or high winds.

Overweight – A truck or axle that exceeds legal weight limits. May require permits or fines if caught at a weigh station or scale.

Overweight Permit – A special permit required when hauling loads above legal weight limits. Typically arranged by the carrier or broker before transport.

Overweight Violation – A citation issued when a truck exceeds axle weight or gross vehicle weight limits. Drivers may be forced to offload cargo and pay fines. Repeat violations can damage CSA scores and company records.

Own Authority – Slang for a driver or carrier operating under their own FMCSA operating authority instead of being leased to another company. Running under your own authority means you handle your own insurance, compliance, load booking, and DOT responsibilities.

Owner Operator (O/O) – A truck driver who owns and operates their own truck, either leased to a carrier or running under their own authority.

Owner’s Manual – The manufacturer’s manual for a truck, covering operation, safety, and maintenance procedures.

P&D (Pickup and Delivery) – Local or regional freight runs that involve multiple stops for picking up and delivering shipments, common in LTL trucking.

Paid Orientation – When a company pays drivers (daily or hourly) while attending orientation.

Pallet – A wooden or plastic platform used to stack and move freight with forklifts. Standard size is 48x40 inches.

Pallet Jack – A manual or powered tool used to move pallets inside trailers, warehouses, or stores.

Paper Logs – Traditional logbooks used before ELDs, still used as backup if an ELD malfunctions.

Parked Out-of-Service – When a truck or trailer is red-tagged by DOT and cannot be moved until repairs are made.

Parking Brake – The spring-loaded brake system that keeps a truck or trailer from moving when parked. Activated by the red/yellow knobs in the cab.

Partial Load – A shipment that doesn’t take up the entire trailer. Also called LTL (Less-than-Truckload). Carriers may combine multiple partial loads from different shippers into one trailer to maximize space. Opposite of a Full Truckload (FTL).

Passenger Authorization Form – A document issued by a carrier that gives official permission for a non-employee passenger to ride in a commercial truck. The form must be signed by the company (and sometimes the passenger) and kept in the truck during the trip. FMCSA requires written authorization for all riders to ensure compliance with safety and insurance rules.

Passenger Policy – A carrier’s official rules about who may ride in a commercial truck with the driver. Passenger policies outline eligibility (such as family members or friends), required documents, and any restrictions like age limits or insurance requirements. Policies vary by company, but FMCSA requires written authorization for any non-employee passenger.

Pay Per Mile (CPM) – A pay method for company drivers, based on cents per mile. Example: $0.55 CPM.

Payload – The actual weight of the freight being hauled. Different from gross weight (truck + trailer + cargo).

Penny Test – A quick way to check tire tread depth using a U.S. penny. The penny is inserted into the tire’s tread groove with Lincoln’s head facing down. If the top of Lincoln’s head is visible, the tread is too shallow and the tire is below legal limits. While not as accurate as a tread depth tool, the penny test is a common roadside check for drivers.

Per Diem Pay – A pay structure where part of a driver’s wages are designated for meals and expenses, offering tax advantages.

Permit Book – A binder in the truck containing required documents, such as registration, insurance, IFTA, cab card, and state permits.

Personal Conveyance (PC) – A rule that allows CDL drivers to operate their truck for personal reasons while off duty, such as driving to find parking, lodging, or food. The truck must not be moved for the purpose of advancing a load. Misuse of PC is a common violation.

Pet Policy – A carrier’s rules about whether drivers can bring pets on the road. Pet policies usually set limits on the type, size, or number of pets allowed and may require a deposit to cover cleaning or damage. Some companies use pet-friendly policies as a recruiting benefit to attract drivers who want companionship on long hauls.

Petro Stopping Centers – A nationwide chain of full-service travel centers, now owned by TA (TravelCenters of America). Known for larger parking lots, maintenance services, and amenities for long-haul drivers.

Pickup Number – A reference number provided by the shipper that confirms a load is ready for pickup. Drivers usually must show this number at the shipping office to get loaded.

Pigtail – The coiled electrical cable that connects the tractor to the trailer, powering lights and ABS.

Pilot Car (Escort Vehicle) – A smaller vehicle that drives in front of or behind a truck hauling an oversize load. Pilot cars warn other drivers, help guide the truck, and ensure the load clears bridges, signs, or tight turns. Some oversize loads require multiple pilot cars by law.

Pilot Flying J – One of the largest truck stop chains in North America, with locations across the U.S. and Canada. Offers fuel, parking, food, showers, and reward programs. Many carriers issue Pilot Flying J fuel cards for driver discounts.

Pilot Flying J Fuel Card – A branded card that gives fleets discounts at Pilot and Flying J truck stops.

Pin Lock – A security device that locks onto the trailer’s kingpin to prevent theft.

Pins – Metal fasteners used throughout truck and trailer systems (suspension, brakes, hitches). They must be secure and not bent or missing.

Placard – Diamond-shaped signs displayed on trucks hauling hazardous materials. Indicate the type of hazmat being transported.

Placard Holder – The frame on a trailer used to display hazardous material placards.

Plate / Base Plate – The truck’s license plate, typically tied to the IRP (International Registration Plan) and required to be carried in the permit book.

Pneumatic Trailer – A type of bulk trailer that uses compressed air to unload dry goods like cement, sand, or grain.

PO Number (Purchase Order Number) – A number assigned by the shipper to identify a load for billing and tracking.

Pole Trailer – A trailer designed to carry long loads like logs, pipes, or utility poles.

Port – A shipping terminal where containers are transferred between ships, rail, and trucks. Truck drivers often haul loads in and out of ports using container chassis. Ports require special clearances, such as a TWIC card (Transportation Worker Identification Credential), to enter and pick up or deliver freight.

Port of Entry – A checkpoint, usually at a state border or near major highways, where commercial trucks must stop for inspection. Officers check driver credentials, vehicle paperwork, and sometimes cargo. Ports of entry often include weigh stations.

Possession of Alcohol in CMV – Federal law prohibits CDL drivers from possessing open containers of alcohol in the cab, even if they are not drinking. Violations can lead to disqualification.

Post-Accident Test – A DOT-required drug and alcohol test performed after certain crashes involving a CDL driver. Testing is required if the accident involves a fatality, a citation with an injury, or a citation with a vehicle being towed. Results are reported to the Drug & Alcohol Clearinghouse.

Post-Trip Inspection (Post TI) – The required inspection drivers perform at the end of the day or duty period. Drivers must note defects in their Driver Vehicle Inspection Report (DVIR) so issues can be repaired before the next trip.

Power Only – A type of load where a carrier provides only the tractor, and the shipper provides the trailer.

Power Unit – The tractor portion of a truck (as opposed to the trailer).

Practical Miles – A mileage calculation method based on the most reasonable, truck-legal routes a driver would normally take between pickup and delivery points. Practical miles are closer to the real distance driven and usually pay more fairly.

Pre-Employment Drug Screen – A DOT-required drug test that all CDL drivers must pass before being hired to operate a commercial motor vehicle. The test screens for marijuana, cocaine, opioids, amphetamines, and PCP. Passing is mandatory before a driver can be added to a company’s drug and alcohol testing program.

Pre-Pass – An electronic system that lets trucks bypass weigh stations if they meet compliance standards.

Pre-Trip Inspection (PTI) – A required inspection drivers perform on their truck and trailer before driving each day. Part of the CDL skills test.

Preventable Accident – An accident that could have been avoided by the driver, even if they weren’t legally at fault. Carriers and safety managers use this term in reviews.

Prime Mover – Another term for a tractor or power unit, more common outside the U.S.

Private Carrier/Fleet – A fleet owned by a company to haul its own goods (example: Pepsi, Walmart). Different from private carrier as it usually means multiple trucks and drivers.

Pro Number – A unique number assigned to a shipment for tracking, commonly used in LTL freight.

Produce Trailer – Specialized vented trailers used for hauling crops like potatoes or produce that don’t always require refrigeration.

Profit Sharing – A company program where employees receive a portion of company profits, usually as a bonus or retirement contribution.

Proof of Delivery (POD) – A signed document (often the bill of lading) confirming freight was delivered.

PSI (Pounds per Square Inch) – A unit of pressure measurement used in trucking, especially for air brakes and tire inflation.

PSP (Pre-Employment Screening Program) – A safety record service managed by the FMCSA that provides carriers with a driver’s 5-year crash history and 3-year roadside inspection history. Carriers use PSP reports when hiring to check a driver’s performance and safety record, including violations that added CSA points. Drivers can request their own PSP report to see what carriers will see before applying for jobs.

PTO (Power Take-Off) – A device that transfers engine power to another piece of equipment, such as a hydraulic pump used on dump trucks or tankers.

PTO (Paid Time Off) – Paid Time Off is the vacation or personal leave that a driver earns as part of their benefits. Instead of only having “sick days” or “vacation days,” PTO rolls them all together. It means a driver can take time off and still get paid their regular wages for those hours or days.

Public Scales – Certified truck scales (like CAT Scales) where drivers can weigh their truck and trailer.

Pull – Slang for hauling a load (example: “I’m pulling a reefer trailer”).

Pup Set – A pair of pup trailers (usually 26–28 feet each) pulled together by one tractor in a doubles configuration. Common in LTL freight.

Pup Trailer – A short trailer, usually 26 to 28 feet long, commonly used in less-than-truckload (LTL) freight. Pup trailers are often pulled in sets of two (doubles) or three (triples) by a single tractor.

Pushrod – A rod that extends from the brake chamber to the slack adjuster. It must not move more than the allowed distance (checked during the CDL pre-trip brake test).

Quad Trailer (Quads) – A setup where a tractor pulls four short pup trailers in a row. This isn’t common in the U.S., but in some parts of Canada you’ll see them used to haul a lot of freight at once on long, open highways.

Qualcomm – A satellite communication and electronic logging system used in many trucks. It allows dispatch to send messages, track loads, and monitor Hours of Service.

Qualifying Miles – Miles that count toward a driver’s pay package, safety bonus, or lease-purchase program. Some companies only pay for “qualifying miles,” which can differ from hub miles or household miles.

Quarantine Zone – A designated area where movement of certain freight, plants, or materials is restricted to prevent the spread of pests or diseases. In trucking, quarantine zones are often set up for agricultural threats, such as the Spotted Lanternfly, and require drivers to follow special inspection and permitting rules before leaving the zone.

Quarter Fender – A small fender mounted over the drive tires to reduce road spray. Shorter than a full fender, often used in pairs.

Quarter Test – A quick way to check tire tread depth using a U.S. quarter. The quarter is inserted into the tire’s tread groove with Washington’s head facing down. If the tread reaches the top of Washington’s head, it equals about 4/32 inch, which is the minimum legal tread depth for steer tires.

Quarterly IFTA Filing – Carriers and owner-operators must file IFTA (International Fuel Tax Agreement) returns every quarter to report miles driven and fuel purchased in each state.

Quarterly Taxes – Estimated taxes that owner-operators must pay to the IRS every three months. Often includes income tax and self-employment tax.

Quick Pay – A freight broker or factoring option that pays carriers faster than standard 30–45 day terms, usually for a small fee or percentage.

Quick Release Valve – A valve in the truck’s air brake system that speeds up the release of air pressure when the brakes are released, improving brake response time.

Quote – An estimate of the cost to move a load, usually given by brokers or carriers based on weight, distance, and type of freight.

Rail Yard – A terminal where freight is transferred between trains and trucks. Truck drivers often pick up or deliver intermodal containers at rail yards, using a container chassis to move them to warehouses, distribution centers, or ports. Rail yards operate similarly to ports but are connected to rail lines instead of ships.

Raised Roof Sleeper – A sleeper with a higher roofline, allowing more standing room inside. Often has space for cabinets, refrigerators, or extra bunks.

Random Drug Testing – A DOT-required part of the CDL drug and alcohol testing program. Drivers are selected at random throughout the year to undergo testing for drugs (such as marijuana, cocaine, opioids, amphetamines, PCP) and alcohol. Selection is unpredictable to ensure compliance at all times. Refusing or failing a random drug test results in an automatic violation being reported to the Drug & Alcohol Clearinghouse, leading to suspension from driving until the return-to-duty process is completed.

Range Selector – A switch on the gear shifter that lets the driver move between low and high ranges in multi-speed transmissions.

Rate Confirmation (Rate Con) – A document from a broker to a carrier that confirms the payment rate, load details, pickup/delivery locations, and terms. Essential for invoicing.

Ready, Set, Truck! (RST) – A trucker success hub that provides guides, tools, and resources to help drivers build skills, manage money, and grow their careers in trucking.

Rear Impact Guard (RIG / ICC Bumper) – A safety bar mounted at the back of trailers to prevent cars from sliding underneath in a collision.

Reasonable Suspicion Test – A test ordered when a supervisor has reason to believe a driver is under the influence of drugs or alcohol while on duty. Supervisors must be trained to recognize signs such as behavior, appearance, speech, or smell.

Recap (Logging Practice) – A Hours-of-Service practice where drivers “recap” hours from 8 days ago and add them back into their available hours. Important for staying compliant on long runs.

Recap (Tires) – A tire that has had a new tread applied to an old casing. Common in trucking to save money, though not always allowed on steer axles. Also called a “retread.”

Receiver – The business or party receiving the freight at the destination. Listed on the bill of lading (BOL).

Reckless Driving – A serious traffic violation for operating a vehicle in a way that shows disregard for safety or traffic laws. For CDL holders, reckless driving is considered a major violation under FMCSA regulations and can lead to heavy fines, CSA points, license suspension, or even disqualification depending on state laws and repeat offenses.

Recover / Recovery Load – A load reassigned to a new driver because the original driver couldn’t deliver it due to breakdown, hours-of-service, or refusal.

Recruiter – A company employee responsible for finding and hiring new drivers.

Redelivery – When a shipment must be delivered again, usually after a rejection or missed appointment.

Reefer (Refrigerated Trailer) – A temperature-controlled trailer used to haul perishable goods like food, pharmaceuticals, or chemicals.

Referral Program – A bonus program where drivers earn money or perks for referring other drivers to their company.

Refuel / Refueling – The act of filling the truck with diesel. Often tracked in logs and receipts for IFTA reporting.

Refusal to Submit to Drug/Alcohol Test – Treated the same as a failed test under FMCSA rules. Refusing a DOT-mandated test leads to automatic out-of-service status and CDL disqualification until the driver completes the return-to-duty process.

Regen (Regeneration) – A process used in modern diesel trucks with diesel particulate filters (DPF). Regen burns off the soot that builds up in the filter by raising exhaust temperatures. It can happen automatically while driving (passive regen) or require the driver to park and start it manually (forced regen).

Regional Haul (Regional Driving) – Trucking work within a set area or group of states, often allowing drivers to get home weekly.

Rejected Load – When a receiver refuses to accept a load due to damage, spoilage, wrong product, or paperwork issues. Rejected freight often has to be returned, disposed of, or resold.

Rejected Trailer – When a shipper or receiver refuses to load a trailer, often because it is dirty, damaged, or not suitable for the load. Drivers may be required to wash out or repair the trailer before reloading.

Relay (Driver Relay / Swap) – When one driver drops a load at a set point and another driver picks it up to continue the trip. Helps keep freight moving nonstop.

Relay (Fuse) – A small electrical component in the truck’s fuse box that acts like a switch to control circuits such as lights, fans, or auxiliary systems.

Reman (Remanufactured Tire) – A tire casing that has been rebuilt to factory specs, not just retreaded. Offers better reliability than a basic recap.

Rest Area – A public stop along highways with parking, bathrooms, and sometimes vending. Used by truckers for short breaks or to log Hours-of-Service time.

Rest Haven – Slang used by drivers for trucker-only rest stops or designated overnight parking areas at shippers, receivers, or yards.

Restricted Lane – A highway lane where truck access is limited or prohibited. Many states require trucks to stay in the right lane except when passing, while some highways have truck-only lanes.

Restricted Route – A road or section of highway where trucks are banned or limited due to weight, height, hazmat rules, or local ordinances. GPS and route planning software warn drivers of restricted routes.

Restricted Zone – An area where trucks may face delivery time limits, curfews, or bans (common in downtowns, tunnels, and near schools). Hazmat and oversize loads often face additional restrictions.

Retarder – A device that helps slow down a truck without using the service brakes, such as engine brakes, exhaust brakes, or transmission retarders.

Return-to-Duty Test – A drug or alcohol test that a CDL driver must pass before returning to safety-sensitive work after a violation. It is part of a monitored program overseen by a Substance Abuse Professional (SAP).

Revenue Miles – Miles driven while hauling a paying load (doesn’t include empty miles).

Rider Insurance – An insurance policy or rider add-on that covers authorized passengers traveling in a commercial truck. Many carriers require drivers to carry rider insurance before allowing family members or friends in the truck. It provides coverage in case of injury or accident involving the passenger.

Rider Policy – A carrier’s official policy that explains whether drivers may carry passengers in the truck. Rider policies often set age limits, require signed authorization, and may require additional insurance. Each company’s rules are different, and FMCSA requires written authorization for any non-employee passenger.

Rider Waiver – A document signed by an authorized passenger before riding in a commercial truck. The waiver acknowledges the risks of traveling in a CMV and often releases the carrier from certain liabilities. Many companies require both a Passenger Authorization Form and a Rider Waiver as part of their rider policy.

Right Lane (Slow Lane) – The far-right lane of the highway, generally reserved for slower vehicles like trucks. Often required by law for trucks in certain states or on steep grades.

Rivets – Fasteners used in truck and trailer construction, especially in flooring, cross members, and panels. Rivets must be checked during inspections for looseness or damage.

Roadside Inspection – A DOT inspection of a truck and driver at a weigh station or roadside stop to check safety compliance.

Road Test – A driving evaluation performed by a carrier or state examiner to measure a driver’s skills.

Rocky Mountain Double – A tractor-trailer combination with one full-size trailer (40–53 feet) and one shorter pup trailer. Often used in western states where longer combinations are legal.

Rookie Trucker (Rookie Driver) – A new commercial driver, typically in their first year of trucking. Rookie drivers are still learning the basics of trip planning, time management, working with dispatch, and handling the challenges of life on the road. Many carriers have specific policies, training programs, or pay scales for rookies until they gain more experience.

Route – The planned path a driver follows to deliver a load. May be set by the company or chosen by the driver.

RPM (Revolutions Per Minute) – A measurement of how fast the engine crankshaft is turning. Critical for proper shifting and fuel efficiency.

Runaway Truck Ramp – An emergency escape lane on steep grades filled with gravel or sand, designed for trucks that lose braking power.

S-Cam – A shaft with an “S”-shaped end that twists when brakes are applied, forcing the brake shoes against the drum.

Safety Audit – A review conducted by the FMCSA on new trucking companies within their first year of operation. It checks compliance with Hours of Service, driver qualification files, vehicle maintenance, and drug/alcohol testing requirements.

Safety Bonus – Extra pay given by carriers to drivers for safe performance, such as accident-free miles, no violations, or clean inspections.

Safety Lane – A designated lane at a trucking terminal, shop, or scale where trucks undergo inspections for safety and maintenance issues. Carriers often require trucks to pass through a safety lane before leaving on a trip.

Safety Rating – A score assigned by FMCSA after a compliance review or audit. Ratings include Satisfactory, Conditional, or Unsatisfactory, which can affect a carrier’s ability to operate.

Safety Triangle (Reflective Triangle) – A reflective warning device placed on the road to alert other drivers when a truck is stopped. Federal law requires drivers to carry three safety triangles or other approved warning devices.

Salvage Company – A business that buys rejected, refused, or damaged freight (like groceries, produce, or overstock) at a discount. Salvage companies resell the freight through secondary markets or liquidation outlets. Brokers and carriers often call salvage companies when a load is turned away by the original receiver. (Note: Also called Reckless Operation in some states. Same violation, different wording).

Salvage Load – Freight that has been refused, damaged, or spoiled and is sold at a discount or turned over to a salvage company.

Satellite Radio – A subscription-based radio service that provides nationwide coverage. Many truck drivers use it for news, weather, and entertainment on the road.

Satellite Tracking – GPS-based systems used by carriers to monitor the real-time location of trucks and trailers. Helps with dispatching, route planning, and estimated time of arrival (ETA).

Scale (Weigh Station / CAT Scale) – A facility where trucks are weighed to check compliance with federal and state weight limits. Can also refer to portable or private CAT scales at truck stops.

SCR (Selective Catalytic Reduction) – An emissions control system found on modern diesel trucks. SCR works together with DEF (Diesel Exhaust Fluid) by spraying DEF into the exhaust stream, where it reacts inside the catalytic converter to break down nitrogen oxides (NOx) into harmless nitrogen and water. SCR is required by law on most newer trucks to meet EPA emission standards.

Seal – A numbered, tamper-evident device placed on trailer doors after loading to ensure cargo security. Breaking or missing seals can result in rejection at delivery.

Self-Certification CDL – When applying for or renewing a CDL, drivers must declare (or “self-certify”) what type of driving they do. This determines whether they must keep a valid Medical Examiner’s Certificate (MEC) on file with their state’s DMV.

Self-Certify – The process drivers must complete with their state’s DMV/CDL office to declare the type of commercial driving they do (interstate, intrastate, exempt, or non-exempt). Drivers self-certify their medical status and must keep it current to maintain a valid CDL.

Service Brake System – The main braking system on a truck or tractor-trailer, operated by the brake pedal. Distinct from the parking brake and emergency brake systems.

Settlement – The breakdown of a driver’s pay, including miles, pay rate, fuel surcharge, deductions, and bonuses.

Shag Driver – A driver who moves trailers around a yard or between short distances, often using a yard truck or “spotter truck.”

Shift Column (Shifter / Gear Stick) – The lever in manual trucks used to change gears. It often includes switches for high/low range or split gears.

Shipper – The company or individual that sends the freight. They are responsible for properly loading, documenting, and securing the cargo before transport.

Shipping Papers (BOL) – The documents that list the details of a load, including the shipper, consignee, cargo description, weight, and any hazardous material classifications.

Shock Absorbers – Hydraulic devices in the suspension system that control spring and axle movement. Leaking or broken shocks are a violation.

Short Haul – A trucking route that covers a relatively short distance, often within 150 miles of the driver’s base. Different Hours of Service rules may apply to short-haul drivers.

Short-Form Medical Card (Medical Examiner’s Certificate) – The wallet-sized certificate drivers carry as proof of passing their DOT medical exam. It is issued by a certified medical examiner after a successful DOT physical and is required for roadside inspections and carrier records.

Short Miles (Household Goods Miles / HHG Miles) – A mileage calculation method based on the shortest possible distance between two ZIP codes, regardless of the actual roads available. Short miles often underestimate the real distance driven, meaning drivers may not be paid for all miles traveled.

Side Kit Trailer – A flatbed trailer equipped with removable side panels and tarps, often used for hauling bulk or irregular loads.

Side Rails – The long steel or aluminum rails running along the sides of a trailer, providing structure and a place to attach load securement devices.

Sight Side Backing (Driver Side Backing) – Backing a trailer toward the driver’s side of the truck, allowing better visibility compared to blind side backing.

Skid Pad – A training facility or paved surface designed to safely simulate slippery driving conditions, used to train drivers on skid control and recovery.

Skid Plate – The flat metal plate on the trailer that sits on top of the truck’s fifth wheel. It helps distribute the trailer’s weight and allows it to pivot during turns.

Skip Talk – CB radio chatter that bounces off the atmosphere and travels long distances, allowing drivers to hear or talk to others far away. It can interfere with local CB conversations.

Slack Adjuster – A lever connected to the pushrod that adjusts brake slack automatically or manually. Must not move more than 1 inch when pulled by hand during pre-trip.

Sleep Apnea – A medical condition where a person’s breathing repeatedly stops and starts during sleep, often causing poor rest and daytime fatigue. In trucking, sleep apnea is a major safety concern because it can increase the risk of drowsy driving and accidents. Drivers diagnosed with sleep apnea may be required to use a CPAP machine or other treatment to stay medically qualified for a CDL. FMCSA regulations require drivers to disclose sleep disorders during their DOT physical.

Sleeper Berth – The compartment in a tractor where drivers can legally log rest breaks or off-duty time. Sleeper berths must meet DOT size and safety requirements.

Sliding Fifth Wheel – A fifth wheel that can be moved forward or backward on the tractor frame to adjust weight distribution between axles.

Sliding Tandems – The mechanism that allows trailer axles (tandems) to slide forward or backward along the trailer frame to balance weight distribution and comply with bridge laws.

Smith System – A defensive driving method used in trucking that includes five key rules: Aim High in Steering, Get the Big Picture, Keep Your Eyes Moving, Leave Yourself an Out, and Make Sure They See You.

Snow Chains (Tire Chains) – Heavy chains installed on tires to provide traction in snowy or icy conditions. Required in some states during winter months and must be carried by law when entering chain control areas.

Solo Driving – When a CDL driver operates a truck alone, without a trainer, mentor, or co-driver. Most new drivers transition to solo driving after completing CDL school and company training. Solo drivers are fully responsible for trip planning, time management, inspections, and delivering loads on schedule.

Soot – Fine black carbon particles produced by incomplete diesel combustion. Excessive soot buildup in the exhaust or oil may indicate engine or emissions system problems.

Spill Kit – A safety kit containing absorbent pads, booms, and protective equipment used to clean up small fuel or hazardous material spills. Often required when hauling hazmat.

Speed Governor (Truck Governor) – A mechanical or electronic device installed on the truck itself to limit the maximum speed. Carriers often set governors between 62–68 mph to improve safety and fuel economy.

Speed Limiter (State Law) – A speed restriction imposed by state regulations specifically on commercial vehicles. For example, in some states trucks are limited to 55 mph on certain highways, even if passenger vehicles can go faster. Violating state truck speed limits can result in tickets, CSA points, and higher insurance costs.

Split Axle Trailer – A type of trailer where the rear axles are spaced farther apart, often used for specialized loads and offering different weight distribution options.

Split Sleeper Rule (Sleeper Berth Provision) – A rule allowing drivers to split their 10-hour off-duty break into two periods (for example, 8/2 or 7/3 hours). This can extend the 14-hour window and give drivers more flexibility in managing time.

Splitter (Gear Splitter) – A small switch on a manual transmission shifter that allows each gear to be split into two (high and low), effectively doubling the number of gears.

Spotted Lanternfly Permit – A certificate required by some states, especially Pennsylvania, for truck drivers and carriers traveling through areas quarantined for the invasive Spotted Lanternfly. Drivers must complete a brief training course provided by the state and carry the permit in their truck. Failure to comply can result in fines during roadside inspections or at agricultural checkpoints.

Spotter – A person who assists a truck driver during backing maneuvers by giving hand signals or radio instructions to prevent accidents. Common on yards, docks and truck stops.

Spreader Bar (Load Bar) – A device used on flatbed trailers to help secure wide or tall loads. It spreads tie-down straps or chains apart to prevent damage to freight and keep loads stable.

Spring Hangers – Brackets attached to the frame that hold suspension springs in place. Cracked or missing hangers are a common inspection issue.

Stack (Exhaust Stack) – The vertical exhaust pipes on a truck that release engine emissions. Commonly seen as chrome stacks rising behind the cab.

Steer Tires (Steers) – The front tires of a commercial truck, mounted on the steering axle. Steer tires are critical for control, handling, and braking. Regulations require them to have at least 4/32 inch of tread depth and be free from defects such as cuts, bulges, or exposed cords.

Steering Gearbox – The component that transfers steering wheel movement to the steering linkage. Must be securely mounted and free of leaks.

Steering Linkage – The rods and joints connecting the steering gearbox to the wheels. Includes pitman arm, drag link, tie rod, and steering arm. No part should be loose or worn.

Step Deck Trailer (Drop Deck) – A flatbed trailer with a lowered deck behind the tractor, allowing taller freight to be hauled without exceeding height limits.

Step Van – A smaller commercial delivery vehicle with a walk-in cab. Commonly used by parcel carriers, food service companies, and local delivery routes.

Stop(s) – Any additional pick-up or drop-off locations on a load besides the main origin and destination.

Stop Pay – Additional pay added when a driver has to make extra stops to pick up or deliver freight along a single route.

Storage Trailer – A trailer that is left at a shipper, receiver, or yard to be used as temporary on-site storage. Storage trailers are not in transit and often sit loaded for extended periods.

Stoughton Trailers – A U.S.-based manufacturer known for producing dry vans, grain trailers, refrigerated trailers, and intermodal equipment. Popular in regional and agricultural freight.

Straps (Cargo Straps) – Heavy-duty tie-down straps used to secure loads on flatbeds or inside trailers. Must meet DOT securement regulations and be rated for the weight of the cargo.

Student Driver – A person training to become a commercial truck driver, usually while attending a CDL school or riding with a company trainer. Student drivers operate under supervision and must follow strict rules until they earn their CDL and gain enough experience to drive solo. Trucks driven by student drivers often display “Student Driver” signs to alert others on the road.

Student Graduate – A driver who has just completed CDL school or company training and is beginning their career.

Super 10 Transmission – A type of Eaton Fuller manual transmission where the driver shifts through 10 gears by splitting gears in each slot, rather than moving the shifter through a traditional H-pattern. It’s designed to reduce shifting effort and is often found in older highway trucks.

Surge (Tanker Surge) – The movement of liquid inside a tanker that shifts forward or backward during braking or acceleration. Surge can push the truck and affect control, making tanker driving more challenging.

Suspension (Air Ride or Spring Ride) – The system of springs, shocks, bushings, and torque arms that supports the truck or trailer, absorbs shocks, and helps protect cargo. Air ride suspensions provide smoother rides compared to spring suspensions.

TA Petro Fuel Card – Similar program for TA and Petro truck stops, offering discounts and account management.

T-Chek – A payment service for fuel and driver expenses. Was merged into EFS but still recognized by some carriers.

Tandem Axles – A set of two axles placed close together on a truck or trailer. Sliding tandems help balance weight between axles and comply with bridge laws.

Tanker Endorsement (N Endorsement) – A CDL endorsement required to haul liquid loads in tank vehicles. Drivers must pass a written test on surge, slosh, and safe handling.

Tanker Surge – The forward and backward movement of liquid inside a tanker when braking or accelerating. Can affect stopping distance and vehicle control.

TCH (Transportation Clearing House) – A payment network used for fuel cards and fleet payments. Later merged into EFS.

Team Driving – When two drivers share one truck and alternate driving shifts. This allows the truck to run nearly nonstop, covering more miles in less time, and is often used for expedited freight.

Terminal – A carrier’s facility where loads are dispatched, trucks are serviced, and drivers report for work. Terminals often include parking, fuel, and maintenance shops.

Termination – When a truck driver’s employment with a carrier is ended. Termination can be voluntary (the driver quits) or involuntary (the company fires the driver). Involuntary termination may affect the driver’s DAC Report and future job opportunities in the trucking industry.

Thirty Minute (30-Minute) Break Rule – A federal Hours of Service regulation that requires CDL drivers to take a minimum 30-minute break after 8 cumulative hours of driving. The break can be logged as off-duty, sleeper berth, or on-duty not driving (such as fueling or loading). This rule is meant to reduce fatigue and is strictly enforced during roadside inspections and log audits.

Three Points of Contact – A safety rule that requires drivers to maintain three points of contact (two hands and one foot, or two feet and one hand) when entering or exiting a truck to prevent slips and falls.

Tie-Downs – Straps, chains, or binders used to secure freight on flatbeds or inside trailers. Must meet DOT securement requirements.

Tire Inflation – The air pressure inside a tire, measured in PSI. Proper inflation is critical for safety, fuel efficiency, and preventing blowouts.

Tire Pressure Monitoring System (TPMS) – An electronic system that monitors tire pressure and alerts the driver if a tire is underinflated or losing air. Increasingly common in modern trucks and trailers.

Tire Pressure Gauge – A handheld tool used by drivers to measure tire PSI. Truck drivers are required to check tire pressure during pre-trip inspections.

Tire Thumper – A tool used by truck drivers to quickly check tire inflation by hitting the tire and listening for the sound.

TMS (Transportation Management System) – Software used by carriers and brokers to plan, track, and manage freight movements.

Torque Arm / Radius Rod – A suspension component that controls axle movement and keeps it aligned. Bushings and mounts must be intact.

Tow Hook / Tow Strap – Heavy-duty equipment used to tow or recover a truck. Tow hooks are built into most tractors, while tow straps or chains are used by recovery vehicles.

Tow Truck (Heavy Wrecker) – A specialized vehicle designed to tow or recover disabled trucks and trailers.

Tractor – The front part of a tractor-trailer combination that contains the engine, cab, and driver’s seat. It’s designed to pull one or more trailers. In trucking, “tractor” is often used interchangeably with “truck.”

Tractor Trailer – A large truck consisting of a tractor (the power unit) and a trailer (the cargo unit). This combination is also called an “18-wheeler” or “semi-truck.”

Trailer – The non-motorized unit hauled by a tractor. Trailers come in many types, including dry van, reefer, flatbed, step deck, and tanker.

Trailer Floor – The wooden or metal surface inside a trailer that supports cargo. Broken or weak floorboards can lead to rejected trailers.

Trailer Mirror (Rear-View for Oversize Loads) – Additional mirrors sometimes added to see the rear of long or wide trailers.

Trailer Roof – The top of a trailer. Must be free of holes or leaks to prevent damage to freight.

Trailer Skirt (Aero Skirt) – A long panel attached to the lower sides of a trailer to improve aerodynamics and reduce wind drag. Trailer skirts help save fuel and are common on modern trailers.

Trailer Tandems – The set of wheels and axles at the back of a trailer that can be slid forward or backward to adjust weight distribution. Proper tandem placement is important for scaling legal axle weights.

Trainer (CDL Trainer) – An experienced CDL driver assigned to teach and supervise new drivers during on-the-road training. Student drivers ride with Trainers to receive hands-on instruction in real-world conditions. They evaluate skills like shifting, backing, trip planning, and safety.

Transflo (Trip Pack Service) – A document scanning and submission system used at truck stops, terminals, and mobile apps to send trip paperwork, bills of lading, and delivery receipts to carriers.

Transmission Fluid – The fluid that lubricates and cools components in an automatic transmission. Must be at proper levels to prevent shifting problems and overheating.

Tread – The patterned surface of a tire that makes contact with the road. Tread provides traction, especially in wet or slippery conditions.

Tread Depth – The measurement of how much tread is left on a tire. DOT requires at least 4/32 inch of tread on steer tires and 2/32 inch on drive and trailer tires. Drivers must check tread depth during pre-trip inspections.

Tread Depth Tool – A small measuring device used to check how much tread remains on a tire. It ensures tires meet DOT legal minimums (4/32 inch on steer tires, 2/32 inch on drive and trailer tires). The tool has a probe that is inserted into the grooves of the tire tread, and the measurement is read on a marked scale. Drivers use it during pre-trip inspections to confirm tires are safe and compliant.

Trip Envelope – A packet of paperwork drivers turn in at the end of a trip, usually containing bills of lading, fuel receipts, scale tickets, and trip sheets.

Trip Planning – The process of mapping out a route, including fuel stops, rest breaks, weigh stations, and delivery times. Trip planning is one of the most important skills for rookie truckers.

Triple Pup (Triples) – A tractor pulling three pup trailers, typically 26–28 feet each. Allowed only in specific states and under special permit rules.

Triples – A combination vehicle consisting of three trailers pulled by one tractor. Triples are only allowed in select states and require a special T Endorsement on the CDL.

Truck Stop – A facility along highways that provides fuel, parking, food, restrooms, showers, and often repair services for truck drivers. Major chains include Pilot Flying J, Love’s Travel Stops, and TA/Petro. Truck stops are key hubs for rest breaks, trip planning, and networking among drivers.

Truckload (TL) – A full truckload shipment that fills an entire trailer. Opposite of LTL (Less-than-Truckload).

Turbo (Turbocharger) – A device that increases an engine’s power and efficiency by forcing more air into the combustion chamber. In trucking, turbos help large diesel engines generate more torque for hauling heavy loads and climbing steep grades.

Turn Radius – The space a truck and trailer need to make a complete turn. Tractor-trailers require much wider turns than passenger vehicles, especially on city streets and intersections.

Turning Knob (Suicide Knob / Spinner Knob) – A knob attached to the steering wheel that allows drivers to turn the wheel quickly with one hand. Banned in some states but still used in yard trucks and certain applications.

Turnpike Double – A combination vehicle consisting of two long trailers (usually 48 to 53 feet each) pulled by one tractor. Allowed only in certain states and on specific highways with special permits.

TWIC Card (Transportation Worker Identification Credential) – A federally issued ID card required for drivers who access secure port facilities. Requires a background check and biometrics (fingerprints).

U-Joint (Universal Joint) – A mechanical component on the driveshaft that allows it to flex and transmit power even when the shaft is at an angle. Critical for smooth power transfer from the transmission to the differential.

Unassigned Driving (ELD Term) – Driving time recorded in an Electronic Logging Device (ELD) that has not been assigned to a specific driver. Carriers must review and reassign this time properly to stay compliant.

Unauthorized Passenger – A person riding in a commercial vehicle without being listed on company policy or FMCSA rider authorization, which can result in violations.

Under CDL (Exempt Vehicle) – Vehicles that do not require a CDL to operate, usually because they weigh under 26,001 pounds GVWR or fall into certain exempt categories (like some farm or emergency vehicles).

Under Load – A term used to describe a truck that is currently carrying freight that has been picked up but not yet delivered. When a driver is “under load,” they are under dispatch and responsible for the safe and timely delivery of that shipment.

Underride Guard (ICC Bumper) – A safety bar mounted under the rear of a trailer to prevent smaller vehicles from sliding underneath in a rear-end collision.

Unhook (Drop) – When a driver disconnects the tractor from the trailer, usually at a shipper, receiver, or yard. Also referred to as “dropping” a trailer.

Uniform Commercial Code (UCC) – A set of standardized business laws used in the U.S. that often governs shipping documents, contracts, and bills of lading in freight transactions.

Uniform Coverage (Minimum Insurance Requirements) – The federally required minimum insurance coverage that trucking companies must carry to operate legally. FMCSA requires most for-hire carriers to maintain at least $750,000 in liability coverage. Many shippers and brokers, however, require carriers to have $1,000,000 in liability coverage to haul their freight.

Uniform Intermodal Interchange and Facilities Access Agreement (UIIA) – A standard contract between intermodal trucking companies and equipment providers (like railroads and ocean carriers) that allows drivers to pick up and drop off containers at ports and rail yards.

Uniform Vehicle Code (UVC) – A model set of traffic laws used by many states as a basis for their trucking and traffic regulations.

Union (Teamsters, etc.) – A labor organization that represents truck drivers and other workers in collective bargaining with carriers. Unions negotiate pay, benefits, and working conditions for members.

Unit – Slang for a tractor or trailer, often used in dispatch or fleet management (e.g., “Unit 245 needs service”).

Unladen Weight – The empty weight of a truck or trailer without cargo, fuel, passengers, or driver.

Unloading – The process of removing freight from a trailer at a delivery location. Unloading may be handled by the driver, a lumper service, or the customer’s staff, depending on the carrier’s policy and contract. Some loads are driver-assist, meaning the driver is expected to help. Unloading time is often tracked for detention pay if it takes longer than the agreed time.

Unsafe Operation of a CMV – A general violation issued when a commercial driver operates a truck in an unsafe manner not covered by more specific charges. This catch-all violation negatively affects CSA scores.

Unsecured Load – Freight that has not been properly tied down, strapped, or blocked. An unsecured load can shift during transit, causing accidents, damage, or fines under FMCSA cargo securement rules.

Upfitting – The process of modifying a truck after purchase with additional equipment or accessories, such as auxiliary power units (APUs), toolboxes, or aerodynamic kits.

Upgrade – In trucking schools and company training programs, “upgrade” refers to a driver moving from trainee status to full solo driver status.

Urban Area Restrictions – City specific rules that limit where or when trucks can operate, often due to traffic congestion, weight restrictions, or noise ordinances.

Utility Pole Clearance – A consideration for oversized loads and route planning, ensuring tall or wide freight can safely pass utility poles and overhead wires.

Utility Trailer – A smaller, lighter trailer often used for local or non-commercial hauling. In trucking, the term can also refer to Utility Trailer Manufacturing Company, a major U.S. manufacturer of semi-trailers.

Utility Trailer Manufacturing Company – One of the largest trailer manufacturers in the U.S., best known for producing dry vans, refrigerated trailers, and flatbeds. Utility trailers are widely used in both regional and long-haul trucking.

Valve (Air Brake Valve) – A mechanical device in the air brake system that controls air pressure flow. Examples include the foot brake valve, relay valve, and trailer supply valve.

Valve Stem – The small stem on a truck or trailer tire where air is added or checked.

Van Trailer (Dry Van) – The most common type of enclosed trailer used in trucking. It hauls general freight that needs protection from weather but not refrigeration.

Vanguard National Trailer Corp. – A U.S. manufacturer producing dry vans and refrigerated trailers. Vanguard trailers are often used by mid-sized and large carriers.

Vehicle Identification Number (VIN) – A unique 17-character code assigned to every vehicle, including trucks and trailers. Used for registration, maintenance records, and tracking ownership history.

Vehicle Inspection Report (VIR) – A report drivers must complete after inspecting their truck and trailer, usually at the end of a shift or trip. It notes any defects, issues, or repairs needed. The VIR is part of DOT compliance and helps ensure equipment is safe before going back on the road.

Vehicle Maintenance Report (DVIR) – Also called a Driver Vehicle Inspection Report. A daily record drivers must complete before and after a trip to document the truck’s condition and any defects.

Violation (Inspection) – A defect or issue found during a DOT roadside inspection or scale inspection, such as faulty brakes, lights not working, or worn tires. These are logged against the carrier and driver’s CSA score.

Violation (Logbook) – An error or false entry in a driver’s logbook or electronic logging device (ELD). Examples include driving past the legal Hours of Service or failing to record time correctly. These violations can result in fines and CSA point penalties.

Viscosity (Oil) – The thickness of engine oil. Truckers may hear this term when choosing the right grade of oil for their engine (e.g., 15W-40).

Visible Inspection – A quick walk-around check of a truck and trailer, looking for obvious safety issues like lights out, flat tires, or fluid leaks.

Visor – The sunshade mounted above the windshield of a truck. Extended visors are a popular customization and help reduce glare during driving.

Vocational Truck – A truck designed for specialized work such as construction, dump hauling, logging, or utility service, rather than over-the-road freight.

Void (Bill of Lading) – A canceled or invalid freight bill. Sometimes happens when paperwork must be corrected and reissued.

Void (Bill of Lading) – A canceled or invalid freight bill. Sometimes happens when paperwork must be corrected and reissued.

Volume Load – A freight load that fills a trailer because of its size (bulk) rather than weight. Example: light but bulky items like empty bottles.

Volvo Trucks – A global truck manufacturer with a strong presence in the U.S. Known for safety innovations, fuel efficiency, and comfortable cabs. Volvo trucks are commonly used in regional and long-haul fleets.

W9 (IRS Form) – A tax form drivers may fill out when working as an independent contractor.

Wabash National – A leading manufacturer of semi-trailers and truck bodies, including dry vans, reefers, flatbeds, and tank trailers. Wabash is recognized for innovation in lightweight and aerodynamic designs.

Warehouse – A building where freight is stored before being distributed or shipped out. Unlike a distribution center, a warehouse is primarily for storage rather than fast-moving freight.

Washington KPRA Permit (40-Foot Permit) – A special permit required in Washington State for trucks whose kingpin-to-rear-axle (KPRA) measurement exceeds the state’s legal limit. Drivers must keep this permit in their truck at all times when operating in Washington. Failing to carry it can result in fines, often up to $500.

Washout – The process of cleaning out a trailer (especially reefers) between loads, often required when switching from one type of cargo to another.

Waybill – A shipping document that lists details about the freight being hauled, including origin, destination, and handling instructions.

Week in the Hole – A payroll practice where drivers don’t get their first paycheck until after the second week of work, leaving them “a week behind” on pay.

Weight Limit – The maximum legal weight a truck and trailer combination can carry on public roads.

Weigh Station – A checkpoint along highways where commercial trucks must stop to be weighed and inspected for compliance with DOT regulations.

Well Car – A type of rail car designed to carry intermodal containers. Truckers encounter these in rail yards.

Western Star Trucks – A premium truck brand owned by Daimler Trucks North America. Known for highly customizable trucks, Western Star is popular for heavy-haul, logging, and specialized applications.

WEX (Wright Express) – A large payment processing company that issues fuel cards for fleets of all sizes. Parent company of Fleet One.

Wheel Alignment – The adjustment of a truck’s wheels to ensure they are set at the proper angles. Proper alignment reduces tire wear and improves handling.

Wheel Chock – A wedge-shaped block placed against a truck’s wheels to keep it from rolling during parking, loading, or unloading.

Wheel Hub – The central part of the wheel that connects the tire and rim to the truck’s axle. It houses the wheel bearings and often contains oil or grease for lubrication. Wheel hubs must be inspected for leaks or damage during pre-trips.

Wheel Seal – A seal that keeps oil or grease inside the wheel hub to lubricate bearings. A leaking wheel seal can cause violations during inspections and may be a safety hazard.

Wheel Studs – The threaded bolts that the wheel lugs attach to, securing the wheel onto the hub. Broken or missing studs are a DOT violation.

Wheelbase – The distance between the front axle (steer axle) and the rear axle(s) of a truck. It affects turning radius, stability, and how weight is distributed.

Windshield Time – Slang for the time spent driving on the road, as opposed to loading, waiting, or doing paperwork.

Windshield Washer Fluid – A cleaning fluid sprayed onto the windshield to maintain visibility. In cold weather, drivers must use washer fluid with anti-freeze properties.

Work Zone – An area of road construction where traffic is reduced or rerouted. Trucks must reduce speed and follow posted warnings.

Wrecker – A heavy-duty tow truck used to recover or tow disabled semis and trailers.

X Placard (Hazmat Code) – In hazardous materials shipping, the letter “X” is used in UN/NA codes to show that a material is not compatible with certain types of packaging. If an “X” appears before a hazmat ID number, it signals stricter restrictions and handling requirements.

X-Dock (Cross-Dock) – A freight terminal where goods are quickly transferred from one trailer to another instead of being stored in a warehouse. Often used in LTL or time-sensitive freight.

X-Ray Inspection – A type of security inspection at ports, borders, or high-security facilities where trailers or containers are scanned for contraband or hidden cargo.

XPO Logistics – A major freight transportation and logistics company that operates in truckload, less-than-truckload (LTL), and intermodal shipping. Drivers may haul freight for XPO or see their trailers on the road.

Xtra Lease – One of the largest trailer leasing companies in North America. Many drivers pull Xtra Lease trailers when working with shippers and brokers.

Yard Check – An inspection of all trailers and equipment in a yard to verify trailer numbers, conditions, and locations.

Yard Jockey (Yard Dog/Hostler) – A small tractor used in distribution centers or warehouses to move trailers around the yard. Yard jockeys position trailers at docks for loading and unloading.

Yard Move – A special duty status in ELDs for moving a truck around a terminal or yard without counting it as driving time.

Yard Spotter – Another term for yard jockey or hostler, the person who drives the yard truck to reposition trailers.

Yard Tractor – The actual truck used by yard jockeys/spotters, built with a short wheelbase and hydraulic fifth wheel for quickly moving trailers.

Yield Lane – A merge lane where drivers must yield before entering highway traffic.

Yield Sign – A road sign that requires drivers to give the right of way before entering or crossing traffic. Common at highway ramps and intersections.

YRC Freight (Now Yellow Corporation) – A major LTL (less-than-truckload) carrier in the U.S. (recently rebranded as Yellow).

Yoke (Driveline Component) – A U-shaped metal part that connects the drive shaft to the transmission at the front and to the differential at the rear. The yoke helps transfer engine power through the drive shaft to the axles and wheels. Without it, the shaft couldn’t rotate properly or stay aligned under load. Bad yokes or worn joints can cause vibration, noise, or even driveline failure.

Yoke Bolt – The bolt that secures the yoke to the drive shaft or differential. A key inspection item in pre-trips.

Zero Emission Vehicle (ZEV) – A truck that produces no exhaust emissions while operating, such as electric or hydrogen-powered trucks. States like California are beginning to require more ZEVs in commercial fleets as part of clean air regulations.

Zero Violation Inspection – A DOT inspection where no violations are found. Considered a “clean inspection” and helps improve CSA scores.

Zig-Zag Load – Slang for freight that’s stacked or placed unevenly inside a trailer, creating balance or weight distribution issues.

Zip Code Routing – A method carriers and brokers use to calculate miles and pay rates based on the origin and destination zip codes rather than actual driven miles.

Zipper Merge – A traffic merging method where vehicles take turns at the merge point, like teeth on a zipper. Truckers often encounter this in construction zones.

Zone (Delivery/Service Zone) – A designated geographic area used for routing, pricing, or scheduling freight. LTL and final-mile carriers often use zones to set rates.

Zoning Laws – Local or state rules that affect where trucks can drive, park, or idle, especially in residential or restricted areas.