CDL Test

What Is the CDL Written Test

The CDL written test is the set of knowledge exams you take at your state licensing agency before you can get a commercial learner’s permit (CLP). Passing the right knowledge tests earns the permit, which then lets you train on the road with a qualified CDL holder before the skills test.

The tests are run by states but built to federal standards from the Federal Motor Carrier Safety Administration (FMCSA). Federal rules require at least 80% correct on each knowledge test and at least 30 questions per test. Most states base their CDL manual on a common national model, so the content is very similar everywhere.

After passing, you must hold your CLP for at least 14 days before the skills test. You must also complete Entry-Level Driver Training (ELDT) with a registered provider before the skills test if your permit was issued on or after February 7, 2022.

How Many CDL Tests Are There

There is one required knowledge test for everyone — general knowledge — plus extra tests that depend on your vehicle and endorsements:

• General knowledge: required for every CDL class.
• Air brakes: for vehicles with air brakes; without it you get an air brake restriction.
• Combination vehicles: required for Class A.
• Endorsement tests: hazardous materials, tank vehicles, passenger, school bus and doubles and triples.

Many drivers take several knowledge tests. After the permit, the skills test covers a pre-trip vehicle inspection, basic control maneuvers and an on-road drive.

Are CDL Tests the Same in Every State

CDL tests are not identical in every state, but they are very similar. Federal rules set the minimum standards, including the 80% passing score, and most state manuals follow the same model. States choose the exact number of questions, the fees, retest waits, testing languages and appointment rules.

If you move, your state of residence is the one that tests you, so always study your own state’s CDL manual.

CDL License Classes: Class A, B and C

The CDL class you need depends on the vehicle: Class A covers heavy combinations that tow more than 10,000 pounds, Class B covers single vehicles of 26,001 pounds or more, and Class C covers smaller vehicles that carry 16 or more people or hazardous materials. Federal rules (49 CFR 383.91) define the three groups that every state uses:

Your class decides which knowledge tests you take. Every applicant takes the general knowledge test, Class A applicants add the combination vehicles test, and the endorsements below add their own tests.

CDL Test Format

Each CDL knowledge test is a multiple-choice exam, usually taken on a computer at the licensing office. You take the general knowledge test plus the extra tests for your license class and endorsements, and you must reach 80% on each one separately.

General Knowledge Test

The general knowledge test covers the core of commercial driving: vehicle inspection, basic control, shifting, managing space and speed, seeing hazards, driving at night and in bad weather, emergencies and transporting cargo safely. It is the longest test and the one every applicant takes. A CDL practice test for general knowledge is the best place to start.

Air Brakes Test

The air brakes test covers how air brake systems work, their parts, how to inspect them and how to use them. Scoring below 80% means you can still get a CDL, but with an air brake restriction that stops you driving vehicles with full air brakes. A CDL practice test for air brakes is worth extra time because the terms are unfamiliar to most new drivers.

Combination Vehicles Test

The combination vehicles test is required for a Class A license. It covers coupling and uncoupling, inspecting a combination vehicle, rollover and jackknife risks, and how trailers handle differently. Use a CDL practice test for combination vehicles before you book this one.

Endorsement Tests: Hazmat, Tanker, Passenger, Doubles and Triples

Endorsements add permissions to your CDL and each has its own knowledge test. The federal endorsement codes are:

A CDL practice test for hazmat, tanker or passenger endorsements should follow the matching section of your state manual.

CDL Test Scoring

The passing score on a CDL test is at least 80% correct on each knowledge test, a federal standard that applies in every state. You must pass each test separately, so a high general knowledge score does not make up for a low air brakes score.

Below 80% on the air brakes test does not stop you from getting a CDL, but it adds an air brake restriction. Our CDL practice test uses the same 80% pass mark.

How Many Questions Is the CDL Written Test

Federal rules require at least 30 questions on each CDL knowledge test, and each state sets the exact length of its tests. Because you usually take several tests, the total number of questions you answer is much higher than for a car license. Your state CDL manual or licensing agency lists the length of each test.

Registration at the DMV and Fees

You register for CDL knowledge tests at your state licensing agency, often called the DMV. Expect to bring identification, proof of residency and a medical examiner’s certificate, and to pass a vision test. Some states take appointments online, others accept walk-ins.

A CDL practice test DMV-style is useful because the office format is simple: you answer on a screen and learn whether you passed straight away.

CDL Requirements Before the Knowledge Test

Before your first knowledge test you apply for a commercial learner’s permit (CLP), and federal rules in 49 CFR 383.71 set these baseline requirements:

• List every state where you held a driver’s license in the previous 10 years, so your driving record can be checked.
• Prove US citizenship or lawful permanent residency, or apply for a non-domiciled permit where your state allows it.
• Be medically examined and certified by a medical examiner if you will drive in non-excepted interstate commerce.
• Complete Entry-Level Driver Training (ELDT) with a registered provider before your first Class A or B skills test, your first passenger or school bus skills test, or your first hazardous materials knowledge test.

Your CLP is valid for no more than one year, and you cannot take the skills test in the first 14 days after it is first issued. States add their own rules, such as residency documents and fees.

How Much Is the CDL Test

CDL fees are set by each state, and there are usually separate charges for the knowledge tests, the permit, the skills test and the license itself. There is no national fee. Check your state licensing agency’s fee page for current prices, and ask whether training schools or employers cover any of them.

How to Prepare for the CDL Test

How long you should study for your CDL permit test depends on how many tests you need, but most drivers spend one to three weeks with the state manual and practice tests. Study one test at a time and only book once you score above 80% consistently.

Plan your weeks with the study planner for exams and track your appointment with the exam countdown.

Practice the CDL Knowledge Tests

The best way to practise for the CDL is with timed questions that explain every answer. Our free CDL practice test covers general knowledge, air brakes, combination vehicles and hazmat awareness, with CDL practice test questions and answers explained. If your road-sign knowledge is rusty, the road signs test and road signs flashcards are quick refreshers.

Prepare for the CDL Road Test

To practise for the CDL road test, train with your ELDT provider and a qualified CDL holder during your permit period. Rehearse the pre-trip inspection out loud until you can name every component in order, and practise the basic control maneuvers, such as backing, until they feel routine. Many drivers fail the pre-trip, not the drive.

Test Day Checklist

CDL knowledge tests are usually not timed in a strict way, but offices have opening hours and queues, so arrive early. Bring everything on this list:

• Identification and proof of residency your state requires.
• Your medical examiner’s certificate and any required forms.
• Payment for the knowledge test and permit fees.
• Glasses or contact lenses if you need them for the vision test.
• A list of the tests you are taking: general knowledge plus air brakes, combination or endorsements.
• A plan for any test you fail, so you know your state’s retest rules.

If you also need workplace safety training, our OSHA practice test guide explains OSHA 10 and 30. For a regular license, start with the DMV practice test.

Frequently Asked Questions

Is the CDL Written Test Hard?

The CDL written test is moderately hard because the passing score is high: federal rules require at least 80% on every knowledge test. The questions come straight from your state’s CDL manual, so drivers who read the relevant sections and take practice tests usually pass. Air brakes and combination vehicles trip up the most people.

How Many Questions Are on the CDL Permit Test?

Federal rules require at least 30 questions on each CDL knowledge test, and your state sets the exact number. The permit test is really several tests: general knowledge for everyone, plus air brakes, combination vehicles or endorsements depending on the license you want. Your state CDL manual or licensing agency lists each test’s length.

How Long Is the CDL Written Test Good For?

Your state decides how long passing knowledge test results count, but federal rules cap a commercial learner’s permit at one year from the date it is first issued. Once you have the permit, you must hold it for at least 14 days before taking the skills test. Check your state licensing agency for its exact validity period and renewal rules.

How Often Can You Take the CDL Test?

Each state sets its own retest rules, including any waiting period between attempts and whether you pay again. Many states allow a retest fairly quickly for knowledge tests, but some require a wait or limit attempts. Check your state licensing agency before you book, and practise until you score above 80% consistently.

Is the CDL Test Multiple Choice?

Yes, the CDL knowledge tests are multiple choice, usually taken on a computer at a state licensing office. The skills test is different: it is a practical exam in the vehicle covering a pre-trip inspection, basic control maneuvers and an on-road drive with an examiner.

Is the CDL Permit Test Easy?

The CDL permit test is not easy if you rely on car-driving experience, because it covers truck-specific topics such as air brakes, cargo securement and vehicle inspection. It is very manageable if you study the state CDL manual and use practice tests, since every question is based on that manual.