A Commercial Driver’s License (CDL) qualifies you to operate large commercial vehicles. Endorsements are add-ons to your CDL that authorize you to drive specific vehicle types or carry specific cargo. Most high-paying driving jobs require one or more endorsements. This guide explains each endorsement, what the test covers, and how to add one to your license.
What Are CDL Endorsements?
Endorsements are letter codes added to your CDL that show you are authorized to operate certain vehicles or transport certain materials beyond the standard CDL scope.
Available endorsements:
- H — Hazardous Materials (HazMat)
- N — Tank Vehicles
- X — Combination of HazMat and Tank (H + N combined)
- P — Passenger Transport
- S — School Bus
- T — Double and Triple Trailers
Each requires a separate knowledge test at the DMV. Some also require additional skills testing. The HazMat endorsement requires a federal background check.
H Endorsement — Hazardous Materials (HazMat)
The HazMat endorsement authorizes you to transport materials classified as hazardous under federal regulations — chemicals, flammables, explosives, and similar cargo.
Why it matters:
HazMat drivers are in high demand. Many tanker, fuel delivery, and chemical transport jobs require this endorsement. It typically commands higher pay.
What the knowledge test covers:
- Hazmat regulations and definitions
- Hazard classes and placard requirements
- Loading, unloading, and handling rules
- Emergency response procedures
- Bulk and non-bulk packaging requirements
- Routes and parking restrictions
Additional requirement — TSA background check:
HazMat is the only CDL endorsement that requires a federal Transportation Security Administration (TSA) background check. This involves submitting fingerprints and paying a fee (approximately $86–$116). The background check must clear before the endorsement is added to your license.
Processing time: The TSA check typically takes 2–8 weeks.
N Endorsement — Tank Vehicles
The Tank Vehicle endorsement authorizes you to drive vehicles designed to transport liquid or gaseous materials in tanks with a capacity of 119 gallons or more.
Common jobs: Fuel delivery drivers, water haulers, chemical tankers, milk transport.
What the knowledge test covers:
- Liquid surge and load shifts during turns and braking
- High center of gravity and rollover risk
- Outage (space left for liquid expansion)
- Baffled vs. unbaffled tanks
- Emergency procedures for liquid spills
- Pumping and hose handling
X Endorsement — HazMat + Tank Combined
If you transport hazardous materials in a tank vehicle — which is common in fuel delivery and chemical transport — you need the X endorsement, which is the combination of H and N.
To get the X endorsement, you must pass both the HazMat (H) and Tank (N) knowledge tests and complete the TSA background check.
P Endorsement — Passenger Transport
The Passenger endorsement authorizes you to drive vehicles designed to carry 16 or more passengers (including the driver). This covers buses, transit vehicles, and large shuttles.
Common jobs: City bus driver, charter bus driver, airport shuttle, casino shuttle.
What the knowledge test covers:
- Passenger loading and unloading procedures
- Standing passenger rules
- Emergency exits and evacuation
- Student management (for bus drivers)
- Railroad crossing rules for passenger vehicles
- Prohibited passenger cargo
Skills test required:
You must pass a skills test (pre-trip inspection, basic controls, road test) in a passenger vehicle. This is in addition to the knowledge test.
S Endorsement — School Bus
The School Bus endorsement is required to drive a school bus with school-age children as passengers. It is an additional endorsement on top of the Passenger (P) endorsement — you must have both P and S to drive a school bus.
What the knowledge test covers:
- School bus-specific regulations
- Student management and behavior
- Loading and unloading at stops
- Railroad crossing procedures for school buses
- Emergency evacuation drills
- Mirror adjustment and blind spot awareness
Additional requirements:
Most states (including New York) require school bus drivers to pass a physical examination and a background check in addition to the DMV tests.
Skills test required:
Must be performed in an actual school bus.
T Endorsement — Double and Triple Trailers
The Doubles/Triples endorsement authorizes you to pull two or three trailers at the same time behind a tractor.
Common jobs: Long-haul freight, LTL (less-than-truckload) carriers, package delivery networks.
What the knowledge test covers:
- Coupling and uncoupling double and triple trailers
- Inspecting the converter dolly
- The danger of rearward amplification (crack-the-whip effect)
- Safe turning and backing with multiple trailers
- Emergency braking with longer combinations
Which Endorsements Pay the Most?
| Endorsement | Typical Pay Premium | Notes |
|---|---|---|
| HazMat (H) | High | Requires TSA background check |
| HazMat + Tank (X) | Highest | Fuel delivery, chemical transport |
| Passenger (P) | Moderate | Transit, charter |
| School Bus (S) | Moderate | Requires P first |
| Doubles/Triples (T) | Moderate | Long-haul freight |
| Tank (N) | Moderate-High | Often paired with HazMat |
How to Add an Endorsement to Your CDL
- Study for the endorsement knowledge test using your state’s CDL manual
- Visit your DMV and take the knowledge test (multiple tests can be taken in one visit)
- Pass the skills test (required for P, S, and T endorsements)
- Complete the TSA background check (required for H and X only)
- Pay the endorsement fee (varies by state, typically $5–$20 per endorsement)
- Receive your updated CDL with the new endorsement letter(s)
You can add multiple endorsements over time as your career progresses.
Prepare for the CDL Knowledge Tests
Every CDL endorsement test draws from the corresponding chapter in the federal CDL manual. Our CDL Practice Tests cover general knowledge CDL content that underpins all endorsement areas.
For pre-trip inspection preparation, see: CDL Pre-Trip Inspection: What You Need to Know
For air brake systems (required knowledge for many endorsements), see: CDL Air Brakes: What Every Driver Needs to Know
Not yet licensed? Start here: How to Get Your CDL in New York: Step-by-Step Guide
For a full breakdown of daily and weekly driving limits, see: CDL Hours of Service Rules: Complete Guide for Drivers
Practice Exam Hub is not affiliated with the FMCSA, any state DMV, or any trucking company. This content is for general informational and educational purposes only. Endorsement requirements vary by state — always verify current rules with your state DMV.
Leave a Reply