CDL Endorsements: Types, Hazmat Rules, and Restrictions

CDL endorsements are codes added to a commercial driver’s license that authorize you to operate specific vehicle types or haul particular cargo. Federal regulations recognize six categories: Passenger (P), School Bus (S), Tanker (N), Doubles/Triples (T), Hazardous Materials (H), and the combined Tanker/Hazmat (X) designation for drivers who hold both H and N.¹ Every endorsement requires a written knowledge test, and some require additional skills testing, training, or a federal background check before your state will add the code to your license.

The Six Endorsements and What Each One Covers

Passenger (P): Required to operate any vehicle designed to carry 16 or more people, including the driver. Knowledge test and skills test.²
School Bus (S): Required to drive a school bus. You must first qualify for the Passenger endorsement, then pass a separate knowledge and skills test for S.³
Tanker (N): Authorizes operating a vehicle designed to haul liquid or gaseous materials in a tank with an aggregate rated capacity of 1,000 gallons or more. Knowledge test only.²
Doubles/Triples (T): Required for pulling double or triple trailers. Knowledge test only.
Hazardous Materials (H): Required to haul cargo that needs hazmat placarding. Knowledge test plus a TSA security screening.
Tanker/Hazmat (X): A combined code placed on your license when you hold both H and N.

Testing and Passing Score

Every endorsement requires a written knowledge test on the safety procedures and operational rules for that vehicle type or cargo. The federal passing score is at least 80 percent.⁴ State fees for adding an endorsement vary, so check with your state driver licensing agency.

The Passenger and School Bus endorsements are the two that require a hands-on skills test in addition to the written exam.¹ The skills test has three parts: a pre-trip vehicle inspection, basic vehicle control maneuvers, and an on-road driving evaluation.⁵ If you use a Commercial Learner’s Permit to practice, you cannot take the skills test during the first 14 days after the CLP is issued.⁶ A CLP can carry P, S, and N endorsements for supervised practice.

Entry-Level Driver Training

First-time applicants for the P, S, and H endorsements must complete Entry-Level Driver Training through a provider listed on FMCSA’s Training Provider Registry.⁷ For P and S, ELDT has to be finished before you take the skills test. For H, it has to be finished before you take the knowledge test.⁸ That last point catches applicants off guard, because H is the only endorsement where training gates the written test rather than a road test.

What the Hazmat Endorsement Adds

The H endorsement has the most involved application process because it requires a security threat assessment from the Transportation Security Administration. You cannot take the hazmat knowledge test until TSA screening is complete.

TSA Screening and Fees

The TSA assessment includes fingerprinting and a criminal background check. As of January 2025, the fee for new and renewing applicants is $85.25, with a reduced rate of $41.00 available for certain applicants.⁹ The assessment and endorsement stay valid for five years, after which you go through the full screening again.¹⁰

Who Can Apply

The hazmat endorsement is not limited to U.S. citizens and permanent residents. Federal regulations also allow refugees, individuals granted asylum, and certain nonimmigrant workers with valid work authorization, among others.¹¹

Criminal History

Certain convictions disqualify you from the endorsement. Permanent disqualifiers include espionage, treason, terrorism-related federal crimes, murder, and improper transportation of hazardous materials.¹² Other felonies, including weapons and explosives charges, are interim disqualifiers that block your application for seven years from the date of conviction or five years from release from incarceration, whichever is later. Checking your record against the regulation before paying the TSA fee can save time and money.

Age Requirements

Federal regulations require drivers in interstate commerce to be at least 21. Drivers between 18 and 20 may hold a CDL for intrastate operations if their state allows it, but they cannot cross state lines with commercial cargo or passengers. The age floor applies to endorsements too, so a 19-year-old with an intrastate CDL and a Passenger endorsement could not drive a charter bus across a state border. If you’re pursuing endorsements for interstate work, 21 is the number that matters.

Military Skills Test Waiver

Active-duty service members and recently separated veterans can skip the CDL skills test under FMCSA’s Military Skills Test Waiver program. States may substitute two years of military experience safely operating trucks or buses equivalent to civilian commercial vehicles for the skills test portion of the exam.¹³

To qualify, you must have operated a military vehicle comparable to the CDL class you want during the two years immediately before applying, with a clean driving record over that period (no DUI, leaving the scene of an accident, reckless driving, or using a vehicle to commit a felony). A commanding officer must certify your experience, including the vehicle class, braking system, and transmission type.¹⁴ If you only drove automatic-transmission military vehicles, that detail transfers over and may result in a transmission restriction on your civilian CDL.

The waiver covers only the skills test. You still have to pass every required written knowledge exam, and the TSA hazmat screening cannot be waived. You must apply within one year of leaving a military position that required commercial vehicle operation.¹³

Restrictions That Can Limit Your Endorsement

Where endorsements expand what you can drive, restrictions narrow it. Restrictions are codes placed on your CDL based on the vehicle you tested in, and they can shut you out of jobs even if you hold the right endorsement.¹⁵

L — No air brake vehicles: Applied if you failed the air brake knowledge portion or tested in a vehicle without air brakes.¹⁶
E — No manual transmission: Applied if you tested in a vehicle with an automatic transmission.¹⁶
O — No tractor-trailer: Applied if you tested in a combination vehicle using a pintle hook or similar connection rather than a fifth wheel.¹⁶
K — Intrastate only: Limits you to your home state, typically tied to age or medical certification.
V — Medical variance: Indicates a medical exemption from standard physical qualification requirements.¹⁵

The L, E, and O restrictions can each be removed by retaking the skills test in a vehicle that doesn’t trigger the restriction: a full air brake system for L, a manual transmission for E, and a fifth-wheel tractor-trailer for O.¹⁶ Testing the first time in a manual-transmission, air-brake-equipped tractor-trailer with a fifth-wheel hitch gets you a CDL with no equipment restrictions from the start.

1
eCFR. 49 CFR 383.93 – Endorsements
2
eCFR. 49 CFR 383.5 – Definitions
3
eCFR. 49 CFR 383.123 – Requirements for a School Bus Endorsement
4
eCFR. 49 CFR 383.135 – Passing Knowledge and Skills Tests
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eCFR. 49 CFR 383.113 – Required Skills
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eCFR. 49 CFR 383.25 – Commercial Learner’s Permit
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eCFR. 49 CFR Part 380 – Special Training Requirements
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Federal Motor Carrier Safety Administration. ELDT Applicability – Training Provider Registry
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Transportation Security Administration. HAZMAT Endorsement
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Federal Motor Carrier Safety Administration. TSA Threat Assessment Extension Notice
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eCFR. 49 CFR 1572.105 – Immigration Status
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eCFR. 49 CFR 1572.103 – Disqualifying Criminal Offenses
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Federal Motor Carrier Safety Administration. Military Skills Test Waiver Program
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Federal Motor Carrier Safety Administration. Application for Military Skills Test Waiver
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eCFR. 49 CFR 383.153 – Information on the CLP and CDL Documents and Driver History
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eCFR. 49 CFR 383.95 – Restrictions