CDL Endorsements: Guides & Practice Tests

A CDL endorsement adds a specific authorization to your license — hauling hazardous materials, driving a tanker, pulling extra trailers, or carrying passengers. Not sure which one you need? Use the tool below. Already know? Jump straight to your endorsement's guide and practice questions.

Find My Endorsement

Answer one question. No CDL knowledge required to use this.

What kind of driving do you want to do?
You may need

HazMat Endorsement (H)

The HazMat endorsement authorizes you to transport placarded hazardous materials — fuel, chemicals, explosives, and similar cargo. It requires a knowledge test and, unlike most endorsements, a TSA Security Threat Assessment (a federal background check with fingerprinting).

Caveat: the TSA process is the long pole here, budget 30–60 days, mostly waiting on the background check, not the test itself.
Study HazMat → Start Practicing →
You may need

Tanker Endorsement (N)

The Tanker endorsement authorizes you to drive vehicles hauling liquid or gas cargo in bulk tanks above a certain capacity — fuel, milk, water, or chemicals. It's a knowledge test only: no skills test, no background check, no ELDT required.

Caveat: if you'll specifically haul hazardous liquids like fuel or chemicals, you likely need Tanker plus HazMat together (the X combination), not Tanker alone.
Study Tanker → Start Practicing →
You may need

Doubles/Triples Endorsement (T)

The Doubles/Triples endorsement authorizes you to pull two or three trailers at once, common at LTL freight carriers. Class A CDL only. Knowledge test only, no skills test or background check.

Caveat: triples are only legal in about 20 states, and only on specific routes. Doubles are far more widely permitted. Check your state before planning a triples-focused job search.
Study Doubles/Triples → Start Practicing →
You may need

Passenger Endorsement (P)

The Passenger endorsement authorizes you to drive vehicles carrying 16 or more passengers including yourself — transit buses, tour coaches, shuttles. Requires a knowledge test, a skills test in a representative passenger vehicle, and ELDT training the first time you obtain it.

Caveat: some states set a lower passenger threshold for their own intrastate rules — confirm your specific state's number.
Study Passenger → Start Practicing →
You may need

School Bus Endorsement (S)

The School Bus endorsement authorizes you to drive a school bus. You need the Passenger (P) endorsement first or alongside it, since a school bus is a type of passenger vehicle. Requires a knowledge test, a skills test in an actual school bus, and a state-administered background check.

Caveat: this is the most heavily regulated endorsement, some states add their own extra certifications (California and Texas both do). Plan for the longest timeline of any endorsement here.
Study School Bus → Start Practicing →
You may need

X Combination (HazMat + Tanker)

X isn't a separate endorsement — it's what appears on your CDL when you hold both HazMat (H) and Tanker (N) at the same time. You'll need to meet both sets of requirements: both knowledge tests, plus the TSA background check that HazMat requires. This is the standard combination for fuel, petroleum, and bulk chemical hauling.

Caveat: there's no separate "X test" to study for — prepare using the HazMat and Tanker materials directly.
Learn About X → Start Practicing →

All Endorsements

Already know what you need? Go straight to the guide and practice test.

What an Endorsement Actually Is

A CDL endorsement is an additional authorization added to your Commercial Driver's License, on top of your base Class A, B, or C license, that permits you to operate a specific vehicle type or transport specific cargo. Without the relevant endorsement, your CDL doesn't authorize that particular activity, even if you're otherwise fully licensed.

Each endorsement requires passing a knowledge test specific to that subject. Some — Passenger and School Bus — also require a hands-on skills test in a representative vehicle. HazMat additionally requires a federal TSA background check, a requirement none of the other core endorsements share.

Endorsements aren't the same as restrictions. A restriction limits what you're allowed to do (for example, an automatic-transmission-only restriction if you tested in an automatic vehicle). An endorsement adds a new capability. They work in opposite directions.

Frequently Asked Questions

What is a CDL endorsement?
A CDL endorsement is an additional qualification added to your Commercial Driver's License that authorizes you to operate a specific vehicle type or carry specific cargo beyond what your base CDL alone allows — such as hazardous materials, tank vehicles, or passenger buses.
How do I know which endorsement I need?
It depends on the type of driving work you want to do. Use the Find My Endorsement tool above — answer what you want to drive or carry, and it will point you to the right endorsement, with an explanation of what it actually allows.
What is the X endorsement?
X is not a separate, independent endorsement. It's the code that appears on your CDL when you hold both HazMat (H) and Tanker (N) at the same time. If you need to haul hazardous liquids in bulk tanks, you need both, and many states display that combination as a single X.
Do all endorsements require a skills test?
No. HazMat and Doubles/Triples require a knowledge test only. Tanker requires a knowledge test only as well. Passenger and School Bus both require a knowledge test and a skills test in a representative vehicle.