CDL endorsements and restrictions explained

The six federal endorsements

Federal rules list the endorsement codes a state must print on a CDL (49 CFR 383.153) and the tests each one needs (49 CFR 383.93). Washington publishes the length of each knowledge test (WA DOL):

Each knowledge test, like the core tests, needs at least 80% correct. The lengths are Washington's; other states may differ. Washington also notes that if you take your skills test or train in a commercial tank vehicle, you must pass the tank knowledge test before it can issue your CLP.

FMCSA says states may add their own codes as long as the license explains them. New York, for instance, has extra endorsements such as W (tow truck) and M (metal coil) (CDL-10, Section 1), which is why the same letter can mean different things in different places.

What each endorsement test covers

The knowledge areas are set in federal rules (49 CFR 383.117 to 383.123):

• Passenger (P): loading and unloading passengers, emergency exits including push-out windows, fires and unruly passengers, railroad crossings and drawbridges, and braking procedures. The skills test must be taken in a passenger vehicle of the class you want.
• Tank (N): cargo surge and how it affects handling, braking empty, full and partly full, baffled versus unbaffled tanks, liquids of different densities, and the effect of grades and curves with filled, half-filled and empty tanks.
• Hazardous materials (H): the hazardous materials table, shipping papers, marking, labeling and placarding, packaging, loading and segregation, attendance, parking and routes, emergency equipment, and emergency response.
• School bus (S): loading and unloading children, stop signal devices, mirrors and flashing lights, emergency exits and evacuation, and railroad crossings. You must first qualify for the passenger endorsement, then take a skills test in a school bus of the same class you will drive.
• Doubles/triples (T): federal rules require only a knowledge test. New York's manual tells T candidates to study its air brakes, combination and doubles sections (5, 6 and 7).

What counts as a tank vehicle

A tank vehicle is a CMV designed to carry liquid or gas in a tank or tanks with an individual rated capacity of more than 119 gallons and an aggregate rated capacity of 1,000 gallons or more, permanently or temporarily attached (49 CFR 383.5). An empty storage tank not designed for transport, temporarily attached to a flatbed, is not a tank vehicle.

The hazmat endorsement: TSA check and training

Hazmat is the endorsement with the most steps. A state may not issue, renew, upgrade or transfer an H endorsement unless TSA has found you are not a security risk, or you hold a valid TWIC (49 CFR 383.141). From TSA's HME page:

• You give documents and fingerprints at an enrollment center; applicants licensed in Florida, Kentucky, Maryland, New York, Pennsylvania, Texas, Virginia and Wisconsin go through their DMV instead.
• The fee is $85.25 for new and renewing applicants, or $41.00 at the reduced rate for some TWIC holders. It is non-refundable.
• TSA recommends enrolling at least 60 days before you need a decision, and says some processing times may exceed 45 days.
• You must generally renew every five years, with new fingerprints. Federal rules require states to renew the H endorsement every 5 years or less.

Since February 7, 2022, a first H endorsement also needs entry-level driver training from a registered provider before the knowledge test, not before the skills test as for the other endorsements (49 CFR 383.71(a)(10)). P and S need ELDT before their skills tests; T and N do not need ELDT. Lawful permanent residents must also give their USCIS alien registration number (49 CFR 383.71(b)(8)).

Endorsements on a learner's permit

Only three endorsements are allowed on a CLP: P, S and N (49 CFR 383.25). Each comes with limits while you practice:

• P or S on a CLP: no passengers other than examiners, inspectors, other trainees and the CDL holder supervising you.
• N on a CLP: empty tank vehicles only, and never a tank that held hazmat and has not been purged.
• H and T cannot go on a CLP at all, so you cannot practice hauling placarded hazmat on a permit.

Federal rules also give the CLP its own restriction codes for these limits, P (no passengers in CMV bus) and X (no cargo in CMV tank vehicle) (49 CFR 383.153). New York, for example, notes that they appear on the CLP only and are not carried onto the CDL issued after you pass all required tests.

Restriction codes

Restrictions mostly come from the vehicle you used for the skills test. The federal codes (49 CFR 383.153, causes from 49 CFR 383.95):

Note that N is both an endorsement (tank) and a restriction (no Class A and B passenger vehicle). Where it sits on the license tells you which.

To remove L, Z or E, you do not retake the whole skills test: the state may give a modified test in a vehicle with the equipment, and for L or Z you must also do the air brake pre-trip inspection and pass the air brakes knowledge test (49 CFR 383.135(b)(7)). Removing O means retaking all three skills tests in a tractor-trailer. Our air brakes test guide covers the test behind L and Z.

Which endorsements to take with your first CDL

Match them to the job. Hauling liquids or gas in bulk tanks needs N, and placarded hazmat in a tank needs both (X). Pulling doubles needs T. Driving a bus needs P, with S on top for a school bus. Because T, N and H need no skills test, adding one later means another knowledge test (and, for H, the TSA check and training first); P and S also need a skills test in the right vehicle. The core tests come first either way: see the general knowledge test and Class A vs Class B.

Our CDL practice tests and the CDL practice pack cover general knowledge, air brakes and combination vehicles. They do not include endorsement tests.

Sources

• 49 CFR 383.93, Endorsements — eCFR (checked October 3, 2026)
• 49 CFR 383.95, Restrictions — eCFR (checked October 3, 2026)
• 49 CFR 383.153, Information on the CLP and CDL documents — eCFR (checked October 3, 2026)
• 49 CFR 383.117 to 383.123, Endorsement knowledge requirements — eCFR (checked October 3, 2026)
• 49 CFR 383.5, Definitions (tank vehicle, hazardous materials) — eCFR (checked October 3, 2026)
• 49 CFR 383.25, Commercial learner's permit — eCFR (checked October 3, 2026)
• 49 CFR 383.135, Passing knowledge and skills tests — eCFR (checked October 3, 2026)
• 49 CFR 383.141, TSA approval of hazardous materials endorsements — eCFR (checked October 3, 2026)
• 49 CFR 383.71, Driver application and certification procedures — eCFR (checked October 3, 2026)
• Commercial Driver's License, Drivers (endorsement and restriction codes) — FMCSA (checked October 3, 2026)
• Hazmat Endorsement (HME) Threat Assessment Program — TSA (checked October 3, 2026)
• CDL knowledge test — Washington State Department of Licensing (checked October 3, 2026)
• New York State Commercial Driver's Manual (CDL-10), Section 1 — NYS DMV (checked October 3, 2026)

passmock is an independent practice service. It is not affiliated with or endorsed by the Federal Motor Carrier Safety Administration (FMCSA), the U.S. Department of Transportation, the American Association of Motor Vehicle Administrators (AAMVA) or any state DMV, DPS or driver licensing agency. Our questions are original practice questions written from the official state CDL manuals and federal regulations; they are not taken from any state's test.