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Endorsements and restriction codes

General Knowledge5 minManual section 1 (Endorsements & Restrictions)

An endorsement ADDS a privilege to your CDL or permit (for example, carrying passengers). A restriction LIMITS what you may drive, usually because of the vehicle you used for your skills test. Some letters are used for both, so read the test question carefully.

The six federal endorsements

You add an endorsement to show you have the special knowledge for a vehicle or cargo. Each needs a special knowledge test; some also need a skills test and training.

  • T — Double/Triple trailers. For Class A drivers who want to pull doubles or triples. Research shows it takes much more skill. Knowledge test only.
  • N — Tank vehicle. For a CMV built to haul liquid or gas in a tank (or tanks) with more than 119 gallons each and 1,000 gallons or more in total, whether the tank is permanently or temporarily attached. Applies to Class A and B; to Class C only when hauling hazmat. Why: liquid in bulk is heavy, shifts (surge), and has a high center of gravity.
  • P — Passenger. For a vehicle designed for 16 or more people including the driver, in any class (A, B or C). Needs a knowledge test, ELDT, and a skills test in a passenger vehicle.
  • H — Hazardous materials. For hauling placarded hazmat (49 U.S.C. 5103; 49 CFR 172 Subpart F) or any amount of a select agent or toxin, in any class. Needs ELDT, a knowledge test on recognizing, handling and transporting hazmat, and a TSA background check (criminal, immigration and FBI records). If TSA finds you are a security threat, it tells you and the state denies the endorsement.
  • X — Tank + hazmat combined. For tank vehicles carrying hazardous materials or waste in placarded amounts. Shows you passed both the tank and the hazmat tests.
  • S — School bus. For driving a school bus in any class. Needs a knowledge test, ELDT, and a skills test in a school bus. You must also hold the P endorsement.

States may add their own extra endorsements beyond these six.

Endorsements on a learner permit (CLP)

Only three endorsements may go on a Commercial Learner's Permit (CLP): P (passenger), S (school bus) and N (tank). You cannot get H, X or T on a CLP.

Each comes with a limit: a CLP with P or S must carry the P restriction (no passengers). A CLP with N must carry the X restriction (no cargo — empty tanks only).

The ten standard restriction codes

Restrictions are mostly based on the vehicle and equipment you use in the skills test. There are ten standard codes:

  • E — No manual transmission. You tested in an automatic. Any transmission that does not work fully on the gearshift-and-clutch principle counts as automatic.
  • K — Intrastate only. You may not drive a CMV in interstate commerce (for example, you certified excepted or non-excepted intrastate). States may also use K for other reasons.
  • L — No air brakes. You did not take or failed the air brakes knowledge test, or tested in a vehicle without air brakes. Bars any brakes that work fully or partly on air.
  • M — No Class A passenger vehicle. You took the passenger skills test in a Class B bus.
  • N — No Class A or B passenger vehicle. You took the passenger skills test in a Class C bus.
  • O — No tractor-trailer. You took the Class A test in a combination joined by a pintle hook or other non-fifth-wheel connection, or in a fifth-wheel combination that is not a truck-tractor/semitrailer. You may not drive a fifth-wheel tractor-trailer.
  • P — No passengers in a CMV bus. For CLP holders with P or S. You may carry only federal/state auditors and inspectors, test examiners, other trainees, and the CDL holder riding with you.
  • V — Medical variance. The driver has a medical variance (waiver) noted on the CDLIS driver record.
  • X — No cargo in a CMV tank vehicle. For CLP holders with N: empty tanks only, and never a tank that held hazmat unless it has been purged of all residue.
  • Z — No full air brakes. You tested in a vehicle with air-over-hydraulic brakes (part air, part hydraulic). You may not drive a CMV with brakes that work fully on air.

States may add more restrictions to the CLP privilege. Memory tip: L = "Lacks air"; Z = only partly air; E = "Easy" automatic.

Same letter, two meanings

N, P and X are both endorsements and restrictions. Endorsement P = may carry passengers; restriction P = may NOT carry passengers. Endorsement X = tank + hazmat; restriction X = empty tank only. Endorsement N = tank vehicle; restriction N = no Class A or B bus. On the test, look for the word "endorsement" or "restriction".

References and scope

The topic reference is listed below. Sources support verification; the lesson itself is here. The current content needs technical and language review before public launch.

Manual reference: 1 (Endorsements & Restrictions)

Official CDL handbook · Utah ↗StatesOur editorial approach

Put it into practice

Educational questions with explanations. The answer review also works without the interactive quiz.

Preparing your questions…

Review questions with answers

  1. How many kinds of federal CDL endorsements are there?
    1. Three
    2. Four
    3. Six
    4. Ten
    Show answer
    Six

    There are six federal endorsements: T, N, P, H, X and S.

  2. Which endorsements are the ONLY ones allowed on a Commercial Learner's Permit (CLP)?
    1. P, S and N
    2. H, N and T
    3. P, H and X
    4. T, S and H
    Show answer
    P, S and N

    Only Passenger (P), School bus (S) and Tank (N) may be added to a CLP.

  3. The tank vehicle (N) endorsement is needed for tanks with an individual capacity of more than ___ gallons and a total of 1,000 gallons or more.
    1. 50
    2. 89
    3. 100
    4. 119
    Show answer
    119

    N applies to tanks over 119 gallons each with an aggregate of 1,000 gallons or more.

  4. Why does hauling liquid in bulk require a special endorsement?
    1. Liquids are always hazardous
    2. The cargo is heavy, shifts, and has a high center of gravity
    3. Tank trucks have no brakes on the trailer
    4. Tankers may only drive at night
    Show answer
    The cargo is heavy, shifts, and has a high center of gravity

    Bulk liquid is heavy, prone to shifting (surge) and has a high center of gravity, causing control problems.

  5. The X endorsement shows that a driver:
    1. Has no restrictions
    2. May drive any tank vehicle with passengers
    3. Passed both the tank vehicle and hazardous materials tests
    4. Is limited to empty tanks
    Show answer
    Passed both the tank vehicle and hazardous materials tests

    The X endorsement combines tank vehicle and hazmat.

  6. To get the passenger (P) endorsement, you must pass a knowledge test, complete ELDT, and:
    1. Pass a skills test in a passenger vehicle
    2. Pass a skills test in any truck
    3. Hold a hazmat endorsement
    4. Have 5 years of driving experience
    Show answer
    Pass a skills test in a passenger vehicle

    P requires a skills test in a passenger vehicle.

  7. A driver who takes the skills test in a vehicle with an automatic transmission gets which restriction?
    1. L
    2. K
    3. Z
    4. E
    Show answer
    E

    E = no manual transmission CMV.

  8. If you fail the air brakes knowledge test, your license will show which restriction?
    1. E
    2. L
    3. O
    4. M
    Show answer
    L

    L means no CMV with any type of air brakes.

  9. A driver tests in a vehicle with air-over-hydraulic brakes. Which restriction is placed on the CDL?
    1. L — no air brakes of any kind
    2. E — no manual transmission
    3. Z — no full air brake CMV
    4. K — intrastate only
    Show answer
    Z — no full air brake CMV

    Z restricts you from vehicles whose brakes work fully on air.

  10. A passenger endorsement applicant who takes the skills test in a Class B bus gets which restriction?
    1. M — no Class A passenger vehicle
    2. N — no Class A or B passenger vehicle
    3. P — no passengers
    4. O — no tractor-trailer
    Show answer
    M — no Class A passenger vehicle

    Testing in a Class B bus gives the M restriction.

  11. A passenger endorsement applicant who tests in a Class C bus gets which restriction?
    1. M
    2. N
    3. V
    4. X
    Show answer
    N

    N restriction = no Class A or B passenger vehicle.

  12. A Class A applicant tests with a truck and trailer joined by a pintle hook. Which restriction results?
    1. E
    2. K
    3. Z
    4. O
    Show answer
    O

    O = no tractor-trailer (fifth-wheel) combination.

  13. A CLP holder with a passenger (P) endorsement may carry:
    1. Paying passengers if a CDL holder is aboard
    2. Up to 15 passengers
    3. Only examiners, inspectors, other trainees and the accompanying CDL holder
    4. Family members only
    Show answer
    Only examiners, inspectors, other trainees and the accompanying CDL holder

    The P restriction bars passengers except auditors/inspectors, examiners, trainees and the CDL holder riding along.

  14. A CLP with a tank (N) endorsement must also carry the X restriction, which means:
    1. Empty tanks only, and never an unpurged tank that held hazmat
    2. Tank and hazmat allowed
    3. No air brakes
    4. Daylight driving only
    Show answer
    Empty tanks only, and never an unpurged tank that held hazmat

    X restriction: may operate only empty tank vehicles; no tank that held hazmat unless purged.

  15. The V restriction code means:
    1. Vehicle is over-width
    2. The driver has a medical variance on record
    3. The driver may drive vans only
    4. No vehicle with a sleeper berth
    Show answer
    The driver has a medical variance on record

    V shows that information about a medical variance is on the CDLIS record.

  16. Which endorsement is needed to pull double or triple trailers?
    1. X
    2. N
    3. P
    4. T
    Show answer
    T

    T = double/triple trailers; it requires a special knowledge test.

  17. You may get a hazardous materials (H) endorsement on your learner permit (CLP).
    1. True
    2. False
    Show answer
    False

    False. Only P, S and N may be added to a CLP.

  18. The K restriction on a CDL means the driver:
    1. Must wear corrective lenses
    2. May not drive at night
    3. May not drive a CMV in interstate commerce
    4. May not carry hazmat
    Show answer
    May not drive a CMV in interstate commerce

    K = intrastate only.