CDL Requirements for Commercial Drivers: Complete FMCSA Qualification Guide

By CarrierLens Compliance Team • Last updated: 2025-04-15

A Commercial Driver's License (CDL) is required to operate a commercial motor vehicle (CMV) in interstate commerce under 49 CFR Part 383. Motor carriers must verify that every driver holds the correct class of CDL with the appropriate endorsements before allowing them to operate a vehicle — and must maintain a copy of the CDL in the driver's qualification file. This guide covers every CDL requirement relevant to carriers operating under FMCSA regulations.

What Is a Commercial Driver's License?

A Commercial Driver's License is a state-issued license that authorizes a driver to operate commercial motor vehicles. CDL requirements are federally standardized under 49 CFR Part 383, which requires states to issue CDLs that meet minimum federal standards. However, CDLs are issued by each state's licensing authority — not by FMCSA directly. Drivers hold a CDL from their home state regardless of how many states they operate in.

CDLs are distinct from regular driver's licenses. They require passing both a knowledge test (written exam) and a skills test (pre-trip inspection, basic vehicle control, and on-road driving evaluation). CDL applicants must also pass the DOT physical examination and meet minimum age requirements.

CDL License Classes

There are three CDL classes, defined by the type and weight of vehicle the driver is authorized to operate:

Class A CDL

A Class A CDL is required to operate any combination of vehicles with a gross combination weight rating (GCWR) of 26,001 pounds or more, where the towed vehicle has a GVWR of more than 10,000 pounds. This covers:

• Tractor-trailer (semi-truck) combinations — the most common Class A application
• Truck and trailer combinations where the trailer exceeds 10,000 GVWR
• Double and triple trailers (with T endorsement)
• Tanker vehicles in combination (with N endorsement)

A Class A CDL holder may also operate Class B and C vehicles.

Class B CDL

A Class B CDL is required to operate any single vehicle with a GVWR of 26,001 pounds or more, or any such vehicle towing a vehicle not exceeding 10,000 pounds GVWR. This covers:

• Straight trucks (box trucks, dump trucks, large delivery vehicles)
• Single-unit passenger buses (city transit buses, school buses with S endorsement)
• Segmented buses
• Large tow trucks

A Class B CDL holder may also operate Class C vehicles but not Class A combinations.

Class C CDL

A Class C CDL is required for vehicles not classified as Class A or B that are either designed to transport 16 or more passengers including the driver, or used to transport hazardous materials in quantities requiring placarding. This covers:

• Passenger vans designed for 16+ passengers
• Small HAZMAT vehicles that don't meet the Class A or B weight thresholds
• Some specialized vehicles

CDL Endorsements

Endorsements are add-on authorizations for specialized vehicle types or cargo. They require passing an additional knowledge test (and in some cases a skills test or background check). The following endorsements are federally defined:

Motor carriers must verify that drivers have the correct endorsements for the loads they will carry. Allowing a driver to haul HAZMAT without an H endorsement, or to pull doubles without a T endorsement, is a serious violation that can result in out-of-service orders and civil penalties.

CDL Restrictions

CDLs may also carry restrictions that limit when or how the driver may operate. Common restrictions include:

• E — No manual transmission: Driver passed skills test in automatic transmission only; may not operate vehicles with a manual gearbox
• L — No air brakes: Driver may not operate vehicles equipped with air brakes (significant limitation for most Class A/B vehicles)
• Z — No full air brakes: May operate vehicles with air-over-hydraulic brakes but not full air brake systems
• O — No tractor-trailer: May not operate tractor-trailer combinations
• M — No Class A passenger vehicle: Limits passenger endorsement to Class B vehicles only
• N — No Class A and B passenger vehicle: Limits passenger endorsement to Class C vehicles only

Motor carriers must check driver CDL restrictions before assigning vehicles. A driver with an L (no air brake) restriction cannot legally operate most commercial trucks. Carriers should note and document any restrictions in the driver qualification file.

Minimum Age Requirements

Age requirements for CDL drivers differ for interstate vs. intrastate operations:

CDL Disqualifying Offenses

Certain offenses result in automatic CDL disqualification under 49 CFR § 383.51. Motor carriers should review driver MVRs carefully for any disqualifying history:

Major Disqualifying Offenses (First Offense)

One-year disqualification for a first offense:

• Driving under the influence of alcohol (BAC 0.04% or higher for CDL holders, 0.08% for non-commercial)
• Driving under the influence of a controlled substance
• Leaving the scene of an accident
• Using a CMV to commit a felony
• Refusing a lawfully required breath or blood test for alcohol
• Driving a CMV while CDL is revoked, suspended, or cancelled for a safety reason
• Causing a fatality through negligent or criminal operation of a CMV

Three-year disqualification: If any of the above offenses occur while transporting hazardous materials requiring placarding.

Lifetime disqualification: A second conviction for any of the above major offenses results in permanent CDL disqualification (some states allow reinstatement after 10 years for non-HAZMAT offenses).

Serious Traffic Violations (60-day / 120-day)

Two serious traffic violations within a 3-year period result in a 60-day CDL disqualification. Three serious traffic violations within 3 years result in a 120-day disqualification. Serious traffic violations include:

• Speeding 15+ mph over the posted limit
• Reckless driving
• Improper or erratic lane changes
• Following too closely
• Violating a traffic control law in connection with a fatal accident
• Operating a CMV without obtaining a CDL
• Operating a CMV without the proper CDL class or endorsement for the vehicle
• Using a handheld mobile telephone while operating a CMV

Railroad-Highway Grade Crossing Violations

First offense: 60-day disqualification. Second offense within 3 years: 120-day disqualification. Third or subsequent offense within 3 years: 1-year disqualification.

Out-of-Service Order Violations

Violating an out-of-service order — operating a CMV that has been placed out of service — results in a 90-day to 1-year disqualification for a first offense, and longer disqualifications for subsequent violations.

Annual CDL Review Requirement

Under 49 CFR § 391.25, motor carriers must review the driving record of each CDL driver at least once every 12 months. The review must include:

• An MVR pulled from every state where the driver holds or held a license during the review period
• A supervisor review and signature noting whether the driver meets the qualification standards in Part 391
• Any corrective action if new violations are discovered that may affect the driver's qualifications

The annual MVR review is one of the most frequently missed DQF requirements. Because it has a 12-month due date that varies by driver hire date, it's easy to let reviews slip. CarrierLens tracks the due date for every driver's annual MVR review and sends alerts when reviews are approaching or overdue.

CDL Records in the Driver Qualification File

Motor carriers must keep the following CDL-related documents in each driver's qualification file under 49 CFR § 391.51:

• A copy (front and back) of the driver's current CDL
• A record of the annual MVR review, including the MVR itself and the supervisor's signed review
• The motor vehicle record obtained at hire (the pre-employment MVR)
• Documentation of any inquiry to state licensing agencies about the driver's CDL status and violations at hire

When a driver renews their CDL or obtains a new license (including after changing states), the carrier must update the DQF with the new license copy within 15 days of notification. Allowing an expired CDL copy to remain in the file without updating it is a common DQF documentation error.

For the full list of all 17+ documents required in a compliant DQF, see our driver qualification file checklist, or explore CarrierLens's DQF software to see how CDL tracking is automated in practice.