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CDL Endorsements and Restrictions: What Every Letter Means
- CDL & Compliance
- 3 min read
- October 28, 2026
Your CDL class says what size of truck you can drive. Endorsements add permission for specific vehicles or cargo, and restrictions take some permissions away. Recruiters read these letters before anything else on your license, so it pays to understand them.
The six federal endorsements
There are six standard federal endorsements, each marked by a letter. States may add their own codes, which must be explained on the license.
Letter | Endorsement | What it allows | What it takes |
|---|---|---|---|
H | Hazardous materials | Hauling placarded hazmat | Knowledge test, federal background check, first-time ELDT theory |
N | Tank vehicle | Hauling liquids or gases in tanks | Knowledge test |
P | Passenger | Vehicles designed for 16+ people | Knowledge and skills tests, ELDT |
S | School bus | School buses | Knowledge and skills tests, ELDT |
T | Double/triple trailers | Pulling doubles or triples | Knowledge test, Class A only |
X | Hazmat + tank combined | Hazmat in tank vehicles (fuel, chemicals) | Holding both H and N |
Which endorsements fit which license class
Class A holders can earn all six endorsements. Class B holders can get all except T, and Class C holders can get H, P and S.
Only three endorsements can be placed on a learner's permit: passenger, school bus and tank. The others require a full CDL first.
Hazmat (H) is the most demanding
The hazmat endorsement requires an extra knowledge test and a background check.
If you are getting H for the first time, you must also complete federal entry-level training for hazmat from a registered provider before the knowledge test.
Tanker (N) and the X combination
The tank endorsement applies to tanks built to carry liquids or gases, generally at 1,000 gallons or more. Drivers who hold both H and N receive the X endorsement, which is common for fuel haulers.
Common restrictions to avoid
Restrictions are codes that limit what you may drive. Many come from the vehicle you used on your skills test, so they are often avoidable with planning.
Code | What it means | How it usually happens |
|---|---|---|
E | No manual transmission | You tested in an automatic truck |
L | No air brakes | You tested in a vehicle without air brakes |
K | Intrastate only | You are under 21 or do not meet interstate medical rules |
M | Class A license, but passenger or school bus only in Class B or C vehicles | You earned P or S in a Class B vehicle |
N | Class B license, but passenger or school bus only in Class C vehicles | You earned P or S in a Class C vehicle |
The E restriction is the one new drivers ask about most. Many large fleets run automatic trucks, so it rarely blocks a first job, but some small carriers, flatbed and heavy-haul operations still run manuals.
Which endorsements are worth getting early?
Tanker and doubles/triples are knowledge tests only, so they are cheap to add and widen your options. Hazmat takes more time and a background check, but it opens tanker fuel, chemical and some higher-paying specialized work.
Do not collect endorsements just to have them. Get the ones that match the freight you actually want to haul, then add more as your plans change.
Key Takeaways
There are six federal endorsements: H, N, P, S, T and X.
Hazmat requires a background check and first-time federal training.
X is automatic when you hold both H and N.
Restrictions like E (automatic only) often come from the truck you test in.
Match endorsements to the freight you want to haul.
Restriction codes and endorsement rules vary by state. Confirm with your state licensing agency.
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