Trucking terms and abbreviations, explained

Checked against official sources · Last reviewed October 6, 2026

Trucking has its own alphabet soup. This glossary explains the abbreviations and words you'll run into on federal and state forms, in plain English, with each definition taken from the regulation, law or agency page listed in the sources (the one insurance-product definition, non-trucking liability, comes from insurance brokers). Where we have a full guide on the topic, the term links to it. On our other guides, the first use of each abbreviation on a page links back here. [1][2][3]

Agencies and official sources

• FMCSA (Federal Motor Carrier Safety Administration): the part of the U.S. Department of Transportation that oversees motor carrier transportation. By law, safety is its highest priority.
• USDOT (U.S. Department of Transportation, also written DOT): the federal executive department, headed by the Secretary of Transportation, that FMCSA belongs to.
• IRS (Internal Revenue Service): the federal agency that administers and enforces the tax laws. Truckers deal with it for the heavy vehicle use tax. See our Form 2290 guide.
• TSA (Transportation Security Administration): the federal agency whose mission is to protect the nation's transportation systems. It runs the security threat assessment for the hazmat endorsement. See hazmat endorsement.
• NAIC (National Association of Insurance Commissioners): provides expertise, data and analysis to the state insurance commissioners who regulate insurance.
• ATRI (American Transportation Research Institute): a not-for-profit research organization that has studied trucking and transportation since 1954.
• CFR (Code of Federal Regulations): the organized collection of the general and permanent rules that federal agencies publish in the Federal Register. FMCSA's rules are in Title 49, written "49 CFR".
• U.S.C. (United States Code): the collection of general and permanent federal laws, arranged by subject.

Sources: [1][2][3][4][5][6][7][8][9][10][11]

Licenses, drivers and testing

• CDL (commercial driver's license): a license issued by your home state, under federal standards, that lets you drive a class of commercial motor vehicle. See CDL requirements.
• CLP (commercial learner's permit): a state permit that, carried with your regular driver's license, lets you practice driving a commercial motor vehicle with a CDL holder beside you. See CDL permit.
• Endorsement: an added authorization on a CLP or CDL that you need to drive certain kinds of commercial vehicles, such as hazmat or passenger. (In insurance, an endorsement is something different: an amendment to a policy.)
• ELDT (entry-level driver training): training from a provider on FMCSA's Training Provider Registry that you must finish before the skills test for your first Class A or B CDL or an upgrade, the skills test for a first passenger or school bus endorsement, or the knowledge test for a first hazmat endorsement. See CDL training.
• TWIC (Transportation Worker Identification Credential): a TSA credential required for workers who need access to secure areas of port facilities and vessels. TSA does a background check before issuing it.
• Owner-operator: in FMCSA's Clearinghouse materials, a self-employed CDL driver who operates under their own authority. Owner-operators must meet the Clearinghouse rules for both drivers and employers.
• DQ file (driver qualification file): the file a motor carrier must keep for each driver it employs. See driver qualification file.
• MVR (motor vehicle record): the report of a driver's driving status and history from the state driver record. Carriers request one within 30 days after a driver starts and at least once every 12 months.
• MRO (Medical Review Officer): a licensed physician who reviews the lab results from an employer's drug testing program and evaluates medical explanations for certain results.
• C/TPA (consortium/third-party administrator): a service company that provides or coordinates drug and alcohol testing for DOT-regulated employers, and can run a shared random testing pool. See DOT drug testing.
• Clearinghouse (Commercial Driver's License Drug and Alcohol Clearinghouse): FMCSA's database where employers report and check drug and alcohol testing information about covered drivers. See Clearinghouse.

Sources: [12][13][14][15][16][17][18][19][20][21][22]

Registrations and filings

• USDOT Number: the ID number FMCSA uses to track a company's safety information from audits, inspections and crash investigations. Companies running commercial vehicles that carry passengers or cargo across state lines must have one. See USDOT number.
• MC (Motor Carrier Docket Number, or MC number): the number FMCSA has historically used to track an operating authority registration. Authority is often identified by an MC, FF or MX number, depending on its type. See MC number and operating authority.
• Operating authority: FMCSA registration that, in general, you need on top of a USDOT Number to haul other people's federally regulated cargo or passengers across state lines for pay, or to arrange that transport. It sets the kind of operation you may run and the cargo you may carry.
• BOC-3 (Designation of Agent for Service of Process): the form that names your process agents. Only one current BOC-3 can be on file, and it must list every required state. See BOC-3.
• Process agent: a representative who can be served court papers in any proceeding brought against a motor carrier, broker or freight forwarder.
• MCS-150 (Motor Carrier Identification Report): the form every interstate motor carrier files with FMCSA, then updates every 24 months. See MCS-150 biennial update.
• UCR (Unified Carrier Registration): a yearly registration and fee for motor carriers (for-hire, private and exempt), brokers, freight forwarders and leasing companies operating in interstate commerce. See UCR.
• Motus: the U.S. Department of Transportation's new registration system for FMCSA customers. See Motus.
• FMCSA Register: where FMCSA publishes notices of operating authority applications. Your insurance filing and BOC-3 are due within 20 days after your notice is published there.
• New entrant: a motor carrier (not based in Mexico) that applies for a USDOT Number to start interstate operations. New entrants are monitored for 18 months and must pass a safety audit. See new entrant safety audit.
• Safety audit: FMCSA's review of a new carrier's safety management systems and a sample of its required records. For property carriers it happens within 12 months of getting the USDOT Number.

Sources: [5][23][24][25][26][27][28][29][30][31][32][33]

Taxes and fuel

• IFTA (International Fuel Tax Agreement): an agreement that lets a licensed carrier report and pay fuel taxes to one base jurisdiction, which passes them on to the other places it drove. See IFTA.
• Base jurisdiction: under IFTA, the member state or province where your vehicles are registered, where your records are kept or can be made available, and where your fleet does some of its driving.
• IRP (International Registration Plan): a reciprocity agreement for registering heavy commercial vehicles (over 26,000 pounds) that travel in more than one jurisdiction, including U.S. states, the District of Columbia and Canadian provinces. See IRP.
• Apportioned registration: IRP registration whose fees are split among the jurisdictions a vehicle travels in, based on the share of distance driven in each. Only the base jurisdiction issues the plate and cab card.
• HVUT (heavy highway vehicle use tax): the federal tax filed with the IRS on Form 2290 for highway vehicles with a taxable gross weight of 55,000 pounds or more. See Form 2290.
• EIN (Employer Identification Number): a free federal tax ID number from the IRS for businesses. You need one to file Form 2290; a Social Security number can't be used.
• HUT (New York highway use tax): New York's tax that requires a certificate of registration and decal for each truck, tractor or other self-propelled vehicle over 18,000 pounds gross weight before it runs on New York highways. See NY HUT.
• KYU (Kentucky weight distance tax license): required for carriers traveling on Kentucky roads with a combined license weight over 59,999 pounds. See Kentucky KYU.
• WDT (New Mexico weight distance tax): applies to most vehicles with a declared gross weight or gross vehicle weight over 26,000 pounds that use New Mexico highways. See weight-distance taxes.

Sources: [7][34][35][36][37][38][39][40][41]

Insurance

• MCS-90 (Endorsement for Motor Carrier Policies of Insurance for Public Liability): an endorsement an insurer adds to a motor carrier's policy as proof of the federally required liability coverage. Carriers keep this proof at their principal place of business. See insurance requirements.
• BMC-91 (certificate of insurance): the form an insurer files with FMCSA showing a carrier's full required liability limits.
• BMC-91X (certificate of insurance): a filing that can show full coverage, or one insurer's layer when several insurers together make up the required limits; each insurer files its own.
• NTL (non-trucking liability): as insurance brokers describe it, liability coverage that protects an owner-operator when the truck is driven "off duty" and isn't under dispatch. See truck insurance types.

Sources: [42][43][44][45]

Vehicles, weights and logs

• CMV (commercial motor vehicle): under FMCSA's safety rules, a vehicle used in interstate commerce that weighs or is rated at 10,001 pounds or more, carries more than 8 passengers (including the driver) for pay or more than 15 not for pay, or hauls hazardous materials in amounts that need placards.
• GVWR (gross vehicle weight rating): the maximum loaded weight of a single vehicle, as set by the manufacturer.
• GCWR (gross combination weight rating): the rating for a truck plus what it tows, either the manufacturer's value on the power unit's label or the sum of the GVWRs (or actual weights) of the truck and trailers, whichever is higher.
• Placarded hazardous materials: for CDL purposes, hazardous materials that must be placarded (signs on the vehicle), plus any amount of certain select agents or toxins. Hauling them needs a hazmat endorsement.
• ELD (electronic logging device): a device that automatically records a driver's driving time and helps record hours of service accurately. See ELD mandate.
• HOS (hours of service): the federal limits on how long CMV drivers may drive and work. For example, a property-carrying driver needs 10 consecutive hours off duty before driving, and can't drive once 14 consecutive hours have passed since coming on duty. See hours of service.

Sources: [12][13][18][46][47]

Everyday trucking words

• Motor carrier: in FMCSA's rules, a for-hire or private carrier, including its officers and the staff who hire, train or dispatch drivers.
• For-hire carrier: a business that transports goods or passengers for pay.
• Private carrier: a business that transports property or passengers by commercial vehicle but not for hire, such as a company hauling its own cargo.
• Exempt commodities: cargo that isn't federally regulated for operating authority. For-hire carriers that haul only exempt commodities don't need operating authority.
• Exempt motor carrier: a carrier whose hauling is exempt from FMCSA's economic regulation under federal law; it must still follow the safety rules.
• Interstate commerce: trade or transportation between states (or countries), through another state, or within one state as part of a trip that starts or ends outside it. See which filings do I need?
• Intrastate commerce: trade or transportation within a state that doesn't count as interstate.
• Broker: a business that arranges, for pay, for an authorized motor carrier to haul property. A carrier arranging loads it is authorized to haul and has legally committed to haul itself isn't acting as a broker.
• Freight forwarder: a business that offers shipping to the public, gathers and combines shipments, takes responsibility for them from pickup to delivery, and uses a carrier for at least part of the trip.
• Lessor: in an equipment lease, the party that grants the use of the equipment (with or without a driver), such as an owner leasing a truck to a carrier.
• Lessee: in an equipment lease, the party that gets the use of the equipment, such as the authorized carrier.
• Deadhead: driving a truck back empty. FMCSA guidance says a truck deadheading while in a carrier's service is still subject to the federal insurance (financial responsibility) rules.
• Bobtail: driving a tractor without a trailer. The same FMCSA guidance applies while in a carrier's service. See bobtail insurance.

Sources: [18][25][26][48][49][50][51]

Common questions