The CDL test has three parts: written knowledge tests, a skills test with a vehicle, and a pre-trip inspection

A Commercial Driver License (CDL) test is not one exam—it is a sequence of three separate evaluations that measure whether you can safely operate a commercial vehicle. The written portion tests your knowledge of traffic laws, vehicle systems, and cargo handling. The skills test puts you behind the wheel of an actual commercial truck to demonstrate you can control it safely. The pre-trip inspection requires you to walk around and check critical systems before driving. You must pass all three to receive your CDL.

The written tests are administered by your state's Department of Motor Vehicles (DMV) or equivalent licensing authority. You take them on a computer or on paper at a DMV office. The skills test is conducted by an examiner who rides with you in a commercial vehicle you provide or rent. You cannot pass one part and skip the others—each is mandatory, and each has its own passing score.

Key Takeaways

  • The CDL written test covers general knowledge, air brakes, combination vehicles, and hazardous materials—the specific tests depend on what class of CDL you are seeking and what endorsements you need.
  • You must hold a valid commercial learner's permit (CLP) for at least 14 days before you can take the skills test, and some states require longer.
  • The skills test includes a pre-trip inspection, a basic control test in a closed course, and a road test—all conducted by a state-certified examiner.
  • Passing scores vary by state but typically require 80 percent or higher on written tests and a score of at least 70 percent on the skills test.
  • You can take the written tests multiple times if you fail, but you usually must wait 24 hours between attempts.

What the written tests cover and how they are scored

The written portion of the CDL test consists of multiple-choice questions on topics that directly affect your safety and the safety of others on the road. The General Knowledge test is required for all CDL applicants and covers vehicle inspection, basic control, shifting, backing, and safe driving practices. If you are seeking a Class A CDL (tractor-trailer combination), you must also pass the Combination Vehicles test. If your vehicle has air brakes, you must pass the Air Brakes test. If you will carry hazardous materials, you must pass the Hazmat test.

Each written test is scored out of a total number of questions—usually 50 for General Knowledge, 20 for Air Brakes, and 30 for Combination Vehicles. Your state's DMV publishes the exact number and passing score. Most states require a score of 80 percent or higher. If you score below the passing threshold, you can retake that specific test, usually after waiting 24 hours. Some states allow you to retake a failed test the same day if you pay an additional fee.

You study for the written tests using the CDL manual published by your state's DMV, which is free and available online or in print at any DMV office. The manual contains all the information covered on the tests. Many people also use third-party study guides and practice tests, which are not official but can help you become familiar with the question format and content.

The skills test: pre-trip inspection, basic control, and road driving

The skills test is conducted one-on-one with a state-certified examiner and takes place over several hours. It has three components, each scored separately. You must pass all three to pass the skills test overall.

The pre-trip inspection requires you to walk around the vehicle and point out or demonstrate critical systems: lights, mirrors, tires, brakes, coupling devices (if applicable), and safety equipment. The examiner asks you questions like "Show me your brake fluid" or "How do you check your air pressure?" You do not have to take apart the vehicle—you show where things are and explain what you are checking for. This portion typically lasts 15 to 20 minutes.

The basic control test takes place in a closed course, usually a large parking lot or training facility. You perform maneuvers such as straight-line backing, offset backing, alley docking, and parallel parking—depending on your state and the class of CDL. The examiner watches for smooth steering, proper use of mirrors, and control of the vehicle. You are scored on accuracy and safety, not speed.

The road test is a 20- to 30-minute drive on public roads with the examiner in the passenger seat. You demonstrate proper acceleration, braking, turning, lane changes, and response to traffic and road conditions. The examiner is looking for safe driving habits, proper mirror checks, smooth handling, and compliance with traffic laws. You will be scored on your ability to control the vehicle and make safe decisions.

How to prepare for the written tests

Start by obtaining your state's official CDL manual from the DMV website or office. Read through it carefully, paying close attention to sections on vehicle systems, braking, backing, and hazardous materials if applicable. The manual is written to match the test questions, so material in the manual is material on the test.

Take practice tests online or on paper. Many states offer free practice tests on their DMV websites. Third-party websites and mobile apps also offer practice questions, though you should verify they are based on your state's current manual. Practice tests help you identify weak areas and become comfortable with the question format. Aim to score consistently above 85 percent on practice tests before you take the real test.

Study in focused sessions rather than cramming the night before. Give yourself at least two to three weeks to prepare if you are new to commercial driving. If you have commercial driving experience, you may need less time, but do not skip studying—the test covers specific regulations and procedures that differ from regular driving.

How to prepare for the skills test

You cannot take the skills test until you hold a valid Commercial Learner's Permit (CLP). To get a CLP, you pass the written tests first, then explore at your DMV. Most states require you to hold the CLP for at least 14 days before you can schedule the skills test. Some states require 30 days or longer. Check your state's rules before you schedule.

Practice driving the actual vehicle you will use on the test. If you do not own a commercial truck, rent one or arrange to practice with a training school. Many CDL training schools provide both classroom instruction and behind-the-wheel practice, and they often have vehicles available for the test itself. Practicing in the exact type of vehicle you will be tested in is far more valuable than practicing in a different truck, because the handling, mirror angles, and backup characteristics vary.

Focus on the three test components separately. Spend time on pre-trip inspection by memorizing the systems and practicing your explanation. Spend time in the closed course practicing backing maneuvers until they become automatic. Spend time on the road practicing smooth acceleration, braking, and lane changes. Many people fail the skills test because they are weak in one area—identify yours and drill it.

Retaking the test if you fail

If you fail any part of the written test, you can retake that specific test. Most states allow you to retake a failed written test after 24 hours. You pay the test fee again. There is no limit on the number of times you can retake a written test, though some states may impose a waiting period if you fail multiple times in a row.

If you fail the skills test, you must wait before retaking it. Most states require you to wait at least one week before you can schedule another skills test. You keep your CLP during this time. If you fail the skills test a second time, the waiting period may be longer—check your state's policy. Some states require you to retake the written tests if you do not pass the skills test within a certain timeframe, typically one year.

When you retake the skills test, you must provide the vehicle again and pay the test fee. If you failed because of a specific weakness—such as backing or pre-trip inspection—focus your practice on that area before your next attempt.

State differences in testing requirements and fees

CDL testing is administered by individual states, so requirements and fees vary. All states follow federal guidelines for the content of the written tests and the basic structure of the skills test, but the exact number of questions, passing scores, and waiting periods between attempts differ. Some states offer the written test in multiple languages; others offer it only in English. Some states allow you to take the skills test in a vehicle with an automatic transmission; others require a manual transmission.

Test fees also vary. Written test fees typically range from $10 to $50 per test, depending on your state. Skills test fees are usually $100 to $300. Some states charge a single fee for all three skills components; others charge separately. If you use a CDL training school, they may charge additional fees for instruction and vehicle rental.

Contact your state's DMV or visit their website to learn the specific requirements, fees, and testing procedures in your state. Do not assume that information from another state applies to yours.

Frequently Asked Questions

Can I take the CDL test if I have a suspended or revoked driver license?

No. You must have a valid regular driver license before you can obtain a CDL. If your license is suspended or revoked, you must resolve that issue first. Once your license is reinstated, you can begin the CDL process.

Do I have to use a training school, or can I study on my own?

You can study on your own using your state's CDL manual and practice tests. However, you must still provide your own vehicle for the skills test, and the examiner will not provide instruction. Many people find that a training school provides structured learning and access to a vehicle, which makes passing easier. Training is not required by law, but it is common.

What happens if I fail the pre-trip inspection part of the skills test?

If you fail the pre-trip inspection, you fail the entire skills test and must retake all three components—you cannot retake just the pre-trip portion. You must wait before scheduling another test and pay the full skills test fee again.

How long is a CDL valid once I pass the test?

A CDL is typically valid for four or eight years, depending on your state and whether you are a hazmat-endorsed driver. You must renew it before it expires by passing a written test and a medical examination. Some states allow you to renew by mail or online without retaking the skills test.

Can I take the written test online from home?

Most states require you to take the written test at a DMV office or an approved testing center in person. Some states have begun offering remote testing, but this is not yet standard. Contact your state's DMV to find out whether remote testing is available in your state.