A CDL endorsement is an add-on authorization stamped on your commercial driver’s license that permits you to operate specific vehicle types or haul specific cargo that a standard CDL does not cover. The right endorsements can unlock significantly higher-paying loads and open specialized career paths — but each one requires passing an additional knowledge test, and some require background checks or medical certifications beyond the standard CDL medical exam.
This guide covers every current CDL endorsement, what it permits, how to get it, and who it’s most valuable for.
Overview of CDL Endorsements
The FMCSA defines the following federal CDL endorsements. Individual states may also issue state-specific endorsements. Each endorsement appears as a letter code on your CDL.
H — Hazardous Materials (Hazmat)
What it allows: Transporting hazardous materials that require placarding under 49 CFR Parts 100–185. This includes gasoline, diesel, chemicals, explosives, compressed gases, and radioactive materials.
Requirements:
- Pass the Hazardous Materials knowledge test (30 questions, 80% passing score)
- Pass a TSA Security Threat Assessment (STA): fingerprinting, criminal background check, and identity verification through the TSA HME program
- Must renew every 5 years (the STA must be repeated at each renewal)
Disqualifying offenses for the H endorsement include felony convictions for crimes involving explosives, terrorism, or transportation security violations. A full list is in 49 CFR § 383.51.
Who needs it: Any driver hauling placarded hazmat loads — gasoline tankers, chemical haulers, propane deliveries, LNG/CNG operations.
Pay premium: $0.05–$0.15/mile above standard rates, or $5,000–$15,000+/year for full-time hazmat operations.
N — Tank Vehicle
What it allows: Operating a vehicle designed to transport liquid or gaseous materials in a tank that is permanently or temporarily attached to the vehicle or chassis. This includes liquid tankers, compressed gas tankers, and bulk liquid food-grade operations.
Requirements: Pass the Tank Vehicle knowledge test (20 questions, 80% passing score). No additional background check required for the N endorsement alone (the H endorsement requires TSA).
Who needs it: Fuel tanker drivers, water haulers, milk haulers, liquid chemical drivers. Note: if the liquid being hauled is also a hazmat, both N and H endorsements are required (or the X endorsement).
Pay premium: Tank vehicle endorsement holders typically earn $3,000–$10,000/year more than dry van drivers in comparable operations.
X — Combination Tank / Hazmat
What it allows: Operating a tank vehicle hauling hazardous materials. The X endorsement is the combination of N and H — it replaces both on your CDL.
Requirements: Pass both the Tank Vehicle and Hazardous Materials knowledge tests, plus complete the TSA Security Threat Assessment.
Who needs it: Gasoline tanker drivers, propane bulk delivery drivers, chemical tanker operators — essentially any driver hauling liquid or gas hazmat in a tank vehicle.
T — Double/Triple Trailers
What it allows: Pulling two or three trailers behind a tractor. Double and triple trailer operations are common in LTL freight, parcel delivery (UPS, FedEx), and certain flatbed operations in western US states where doubles/triples are permitted on highways.
Requirements: Pass the Double/Triple Trailers knowledge test (20 questions). Note: the T endorsement is only applicable if you hold a Class A CDL, and doubles/triples are only legal on roads where state/provincial law permits them.
Who needs it: LTL drivers at major parcel carriers (UPS Freight, FedEx Freight, USPS contracted carriers) and western US OTR operations.
P — Passenger
What it allows: Operating vehicles designed to carry 16 or more passengers (including the driver). Includes motorcoaches, charter buses, and transit buses.
Requirements: Pass the Passenger Vehicles knowledge test (20 questions). Must also pass a skills test in an actual passenger vehicle. Many states require additional annual medical certifications for passenger vehicle operators.
S — School Bus
What it allows: Driving a school bus — a vehicle designed to carry school-age children to/from school or school-related activities. Requires the P endorsement as a prerequisite in most states.
Requirements: Pass the School Bus knowledge test (20 questions) and the P endorsement test. State-level background checks (criminal history, sex offender registry) are typically required. Skills test must be conducted in an actual school bus.
Which Endorsements Are Worth Getting?
The endorsements most worth pursuing for income and career flexibility, in order of ROI:
- H/X (Hazmat/Tanker): Highest pay premium, consistently high demand, opens the entire petroleum/chemical hauling sector
- N (Tank): Lower barrier than H (no TSA check), opens non-hazmat liquid tanker work (food-grade, water, milk)
- T (Doubles/Triples): Easy to obtain, required at most major LTL carriers
- P + S (Passenger/School Bus): Niche use case, best for drivers seeking home-daily local schedules over income maximization
Frequently Asked Questions
Can I get a Hazmat endorsement with a felony on my record?
It depends on the nature of the felony. Under 49 CFR § 383.51, certain felony convictions permanently disqualify a driver from holding a Hazmat endorsement — including convictions related to explosives, transportation security offenses, espionage, sedition, treason, and murder. Other felonies may not be disqualifying. The TSA evaluates each application individually. Consult the TSA HME program for your specific situation before investing in training.
How long does it take to get a Hazmat endorsement?
The TSA background check is the main time variable. Processing typically takes 2–6 weeks, but can be faster or slower depending on volume. You can study for and pass the knowledge test while your TSA application is being processed. Budget 4–8 weeks from application to endorsement in hand.
About the Author
Marcus Reid is a former OTR driver and CDL training instructor with 18 years of combined industry experience. → Back to the CDL Training & Trucking Careers Center
Sources
- FMCSA — CDL Information and Endorsements
- FMCSA — Hazardous Materials Regulations
- TSA — Hazmat Endorsement Threat Assessment Program
- 49 CFR § 383.51 — Disqualification of Drivers
Disclaimer: Endorsement requirements, disqualifying offenses, and procedures vary by state and are subject to regulatory change. Always verify current requirements with your state DMV and the relevant federal agencies before pursuing an endorsement.