A CDL comes with specific restrictions on what you can drive and who can sit in your cab

A Commercial Driver's License (CDL) is not a blank permission to drive anything larger than a regular car. It is a tiered license that restricts you to certain vehicle classes and cargo types based on which endorsements you hold and which restrictions are printed on your card. The restrictions exist because different vehicles require different skills, and some cargo is dangerous enough that only trained drivers can haul it. Understanding what your CDL does and does not allow you to do is the difference between a legal day at work and a violation that costs you your license.

Your CDL restrictions fall into three categories: the class of vehicle you can drive, the cargo you can carry, and the passengers you can transport. A restriction code on your license—printed as a letter or number—tells you what you cannot do. If you drive outside those restrictions, you are operating without a valid license for that vehicle, which is a criminal offense in most states.

Key Takeaways

  • CDL classes (A, B, and C) determine the size and weight of vehicles you can legally operate, and driving a heavier vehicle than your class permits is a serious violation.
  • Endorsements like Hazmat and Tanker allow you to carry specific cargo; without them, you cannot haul those materials even if you hold a CDL.
  • Restriction codes printed on your license (such as "L" for no air brakes or "Z" for no passenger seating) are legally binding limits on how you can use your CDL.
  • Medical conditions, violations, and failed tests can result in restrictions being added to your license or your CDL being downgraded to a lower class.
  • Some restrictions are temporary—such as those imposed after a violation—while others remain until you pass a new test or medical exam.

CDL class restrictions: what vehicle size you can drive

Your CDL is issued in one of three classes, and each class has a maximum Gross Vehicle Weight Rating (GVWR)—the total weight the vehicle is designed to carry when fully loaded. You cannot legally drive a vehicle heavier than your class allows, even if you think you can handle it.

Class A allows you to drive any combination of vehicles with a GVWR of 26,001 pounds or more, as long as the towed vehicle weighs more than 10,000 pounds. This includes tractor-trailers, doubles, and triples. Class B allows you to drive a single vehicle with a GVWR of 26,001 pounds or more, or any such vehicle towing a vehicle under 10,000 pounds. This covers straight trucks and buses. Class C is the most restrictive and applies to vehicles that require a CDL but do not fit Class A or B—typically vehicles carrying hazardous materials or 16 or more passengers.

If you hold a Class B CDL, you cannot legally operate a tractor-trailer, even for one trip. If you hold a Class C and attempt to drive a Class A vehicle, you are driving without a valid license. The penalties include fines, points on your record, and suspension of your CDL.

Endorsements you must have to carry certain cargo

An endorsement is a special authorization added to your CDL that allows you to haul specific types of cargo or passengers. Without the endorsement, you cannot legally carry that cargo, even if your vehicle and skills are otherwise suitable.

Hazmat (H) endorsement is required to transport hazardous materials—explosives, flammable liquids, poisons, radioactive materials, and other dangerous goods. To obtain it, you must pass a written test and pass a federal background check. Tanker (N) endorsement is required to haul liquids or gases in a tank vehicle, because the cargo shifts during braking and acceleration in ways that require specific training. Passenger (P) endorsement is required to transport 16 or more passengers (including the driver). School Bus (S) endorsement is required to drive a school bus and involves additional background checks and training.

If you are assigned to haul a tanker load and you do not hold the N endorsement, you cannot legally take that job. Doing so is a violation that can result in fines and loss of your CDL. Some drivers hold multiple endorsements; others hold only the ones their job requires.

Restriction codes that limit how you can use your CDL

Restriction codes are letters or numbers printed on your CDL that tell you what you cannot do. These are not suggestions—they are legal limits. Common restrictions include:

  • L: No air brakes. You can only drive vehicles with hydraulic or spring brakes. If you failed the air brake test during your CDL exam, this restriction is automatically added.
  • Z: No passenger seating. You cannot transport passengers, even if you hold a Passenger endorsement.
  • N: No tank vehicles. You cannot haul tanker cargo, even if you hold the Tanker endorsement (this restriction is sometimes added after a violation).
  • O: No tractor-trailer combinations. You can drive a straight truck but not a tractor pulling a trailer.
  • V: Medical variance. You have a medical condition that requires special monitoring, and your CDL is valid only under the terms of your variance.

If your license shows restriction L, you cannot legally operate an air brake vehicle. If it shows restriction Z, you cannot pick up passengers. Violating a restriction is treated the same as driving without a valid license and can result in criminal charges, fines, and CDL suspension.

Medical conditions and restrictions

The Federal Motor Carrier Safety Administration (FMCSA) requires CDL holders to meet certain medical standards. If you have a condition that does not meet those standards—such as uncontrolled diabetes, severe hearing loss, or certain vision problems—you may still be issued a CDL with restrictions or a medical variance.

A medical variance (restriction V) allows you to drive despite not meeting the standard, but only under specific conditions set by the FMCSA. For example, you might be required to have your vision checked every year instead of every two years, or to carry a letter from your doctor. If you do not comply with the terms of your variance, your CDL becomes invalid.

Some medical conditions result in a downgrade rather than a variance. If you develop a condition that makes you unsafe to drive a Class A vehicle, your CDL may be downgraded to Class B. You would then be restricted to smaller vehicles and would need to retake the CDL exam at the lower class level.

Restrictions imposed after violations or failed tests

Restrictions can be added to your CDL after you commit a violation or fail a test. If you are caught speeding in a commercial vehicle, you might receive points on your record but keep your full CDL. However, if you are caught driving a vehicle you are not licensed for, or carrying cargo you are not endorsed to carry, your CDL can be suspended or downgraded.

If you fail the air brake component of the CDL exam, you automatically receive restriction L (no air brakes). You can still drive vehicles with hydraulic brakes, but you cannot operate air brake systems until you retake and pass that portion of the exam. Some states allow you to remove this restriction by passing a retest; others require you to wait a set period before retesting.

Violations such as reckless driving, driving under the influence, or leaving the scene of an accident can result in temporary restrictions or permanent loss of your CDL. A single DUI conviction typically results in a one-year CDL suspension for a first offense and a lifetime ban for a second offense.

Passenger and cargo restrictions

Even if you hold a CDL, you may not be allowed to transport certain types of cargo or passengers. Without the Passenger endorsement, you cannot legally transport 16 or more people. Without the School Bus endorsement, you cannot drive a school bus, even if you hold a Passenger endorsement.

Some restrictions are job-specific. A driver hired to haul dry goods cannot legally switch to hauling hazardous materials without first obtaining the Hazmat endorsement. A driver restricted from carrying passengers cannot pick up hitchhikers or transport coworkers, even on a short trip, if that restriction is on their license.

Cargo restrictions also explore to the type of load. If your CDL does not include the Tanker endorsement, you cannot haul any liquid or gas in a tank vehicle—not even a partially full tank. The restriction exists because tanker vehicles require different braking and handling techniques than dry vans.

How to remove or modify restrictions

Some restrictions are permanent unless you take action to remove them. If you have restriction L (no air brakes), you can remove it by scheduling a CDL retest that includes the air brake component and passing it. Once you pass, you can request that your state's DMV issue a new CDL without the restriction.

Medical restrictions can sometimes be removed if your condition improves or is successfully treated. If you had a vision problem that resulted in a restriction, and you have since had corrective surgery, you can request a new medical examination. If you pass, the restriction may be removed. However, you must initiate this process—the DMV will not automatically retest you.

Restrictions imposed after a violation typically cannot be removed until a set period has passed or until you meet specific conditions. If your CDL was suspended for 30 days due to a violation, you cannot legally drive commercially during that suspension. After the suspension ends, you can request reinstatement, but you may need to pay a reinstatement fee or provide proof that you have completed a remedial training course.

Frequently Asked Questions

Can I drive a vehicle that is slightly over my CDL class weight limit?

No. The weight limit for your class is a legal boundary, not a guideline. Driving a vehicle that exceeds your class GVWR by even 100 pounds is a violation and can result in fines, points, and CDL suspension. The only exception is if the vehicle is registered at a lower GVWR than it is designed for, which is rare.

What happens if I get caught driving without an endorsement I need?

You are considered to be operating without a valid CDL, which is a criminal offense in most states. Penalties typically include fines ranging from several hundred to several thousand dollars, points on your record, and possible CDL suspension. A second offense within a set period usually results in a longer suspension or permanent loss of your CDL.

Can I remove a medical restriction if my doctor says I am fine?

Your personal doctor's opinion is not enough. You must pass an official medical examination conducted by a FMCSA-certified medical examiner. If you pass, you can request that your state DMV issue a new CDL without the restriction. The process typically takes several weeks.

If I hold a Class A CDL, can I drive a Class B vehicle?

Yes. A higher class CDL allows you to drive any vehicle in a lower class. A Class A holder can drive Class B and Class C vehicles. However, the reverse is not true—a Class B holder cannot legally drive a Class A vehicle.

Do restrictions follow me if I move to another state?

Yes. CDL restrictions are part of your federal driving record and transfer between states. If you move and obtain a new state CDL, your restrictions come with you. However, some states may add additional restrictions based on their own rules, so it is worth checking with your new state's DMV.