A CDL is a special license required to drive certain large or hazardous vehicles for work
A Commercial Driver's License (CDL) is a separate credential from a regular driver's license. You need one if you drive a truck, bus, or vehicle carrying hazardous materials for pay — even if you only drive it part of the time. The federal government sets the baseline rules, but each state issues its own CDL and decides some details about testing and fees.
The key difference: a regular license lets you drive a personal vehicle. A CDL lets you drive vehicles that are too large or carry cargo too dangerous for an unlicensed driver to operate on public roads. If your job involves moving goods or passengers in a commercial vehicle, your employer will require a CDL before you start.
You cannot straightforward add a CDL to your existing license. You have to pass separate written tests and a driving test specific to commercial vehicles. The process takes weeks to months, depending on how quickly you study and schedule your tests.
Key Takeaways
- A CDL is required to drive trucks over 26,001 pounds, buses carrying passengers, or any vehicle carrying hazardous materials, whether full-time or part-time.
- You must hold a valid regular driver's license before you can obtain a CDL, and you cannot hold both a CDL and a regular license at the same time.
- CDL testing includes a written exam on traffic laws and vehicle operation, plus a practical driving test in an actual commercial vehicle.
- States charge different fees and have different renewal schedules for CDLs, typically ranging from $50 to $300 for the initial license.
- Some CDL holders need medical certification from a Department of Transportation-approved doctor before they can drive, depending on the type of vehicle and route.
The three classes of CDL and what each one covers
CDLs come in three classes — A, B, and C — based on the vehicle's weight and what it carries. Class A is the broadest: it covers trucks weighing more than 26,001 pounds that tow a trailer weighing more than 10,000 pounds. Most long-haul truckers and many delivery drivers hold a Class A CDL.
Class B covers single vehicles weighing more than 26,001 pounds that do not tow a trailer, or vehicles towing a trailer under 10,000 pounds. School bus drivers, city transit drivers, and some delivery truck operators hold Class B licenses.
Class C is the least common. It covers vehicles under 26,001 pounds that carry hazardous materials, or vehicles carrying 16 or more passengers (including the driver). You might hold a Class C CDL if you drive a small hazmat truck or operate a passenger van for a tour company.
You can also add endorsements to any class — these are special permissions for specific cargo or driving conditions. A Hazmat endorsement lets you carry dangerous goods. A Passenger endorsement lets you carry people for pay. A Tanker endorsement lets you haul liquids in bulk. Each endorsement requires its own written test.
Who is required to have a CDL
You need a CDL if you drive a commercial vehicle for work — and "work" is broader than you might think. It includes driving for your own business, driving for an employer, or even driving occasionally as part of a job that is not primarily about driving. A real estate agent who occasionally drives a company truck to show properties, or a construction supervisor who operates a company van, may need a CDL depending on the vehicle's weight and cargo.
The rule hinges on three things: the vehicle's weight, what it carries, and whether you are driving it for compensation (money, goods, or any form of payment). A personal vehicle you own and drive for yourself does not require a CDL, even if it is large. A vehicle you drive for any form of work does.
Some states have exemptions for farm vehicles, military vehicles, or emergency vehicles, but these are narrow. If you are unsure whether your job requires a CDL, ask your employer or contact your state's Department of Motor Vehicles — they can tell you based on the specific vehicle and route.
The written test and what it covers
Before you take the driving test, you must pass a written exam. The test covers federal and state traffic laws, vehicle operation, cargo handling, and safety procedures. Most states give you a study manual (often free on the DMV website) that outlines exactly what the test covers.
The general knowledge test is required for all CDL holders. It covers topics like braking systems, steering, load securement, and how to handle emergencies. You typically have 60 minutes to answer 50 questions, and you need to score at least 80 percent to pass.
If you are seeking endorsements, you take additional tests. The Hazmat test covers regulations for transporting dangerous goods. The Passenger test covers passenger safety and emergency procedures. The Tanker test covers the physics of hauling liquids. Each endorsement test is separate and takes about 30 to 45 minutes.
You can retake a failed test, but most states require you to wait a day or a few days before trying again. Some states charge a fee each time you test.
The driving test and what happens during it
The practical driving test happens in an actual commercial vehicle — usually a truck or bus provided by a testing facility or your training school. The test has three parts: a vehicle inspection, a basic control test, and an on-road driving test.
In the vehicle inspection, you walk around the truck or bus and point out safety features and maintenance items. The examiner asks you to identify lights, mirrors, brakes, tires, and other components, and to explain what you are looking for. This part tests whether you know how to do a pre-trip inspection before you drive.
In the basic control test, you drive the vehicle in a closed course — usually a parking lot or training area — and perform maneuvers like backing up, turning, and parking. You have to stay within marked boundaries and show that you can control a large vehicle in tight spaces.
In the on-road test, you drive the vehicle on public roads for 30 to 60 minutes while the examiner watches. You navigate traffic, make turns, merge, and follow the examiner's directions. The examiner is looking for safe driving habits, smooth handling, and your ability to follow traffic laws.
If you fail any part of the test, you can retake it, but you usually have to wait a few days and pay a retesting fee.
Medical certification and DOT physical requirements
Most CDL holders must pass a medical exam from a Department of Transportation-certified medical examiner before they can drive. This is not the same as a regular doctor's visit — it is a specific exam that checks your vision, hearing, blood pressure, and ability to operate a vehicle safely.
The exam looks for conditions that could make driving unsafe: uncontrolled diabetes, heart disease, sleep apnea, or certain medications that impair judgment. If you have a condition that might disqualify you, the examiner can sometimes issue a conditional certificate or require you to see a specialist.
Once you pass, you receive a Medical Certificate that you carry with your CDL. The certificate is valid for one to two years, depending on your health status. When it expires, you have to get another exam. Some states allow you to renew your CDL without a new medical exam if your certificate is still valid, but others require both to happen at the same time.
How to get your free guide: the steps from here
First, check your state's CDL handbook (available free on your state DMV website) to confirm which class and endorsements you need for your job. Read through the study material and take any practice tests your state offers online.
Second, schedule a medical exam with a DOT-certified examiner. You need the medical certificate before you can take the written test in most states. Find examiners through your state DMV website or ask your employer if they have a preferred provider.
Third, study the written test material and schedule your written exam at your local DMV or testing center. Once you pass, you can move on to the driving test.
Fourth, arrange access to a commercial vehicle for the driving test. Some people use a vehicle from their employer or training school; others hire a private testing facility that provides the vehicle. Schedule your driving test with your state DMV.
Fifth, take the driving test. If you pass all three parts, you receive your CDL. If you fail, you can retake the failed section after waiting the required number of days.
Frequently Asked Questions
Can I get a CDL if I have a regular driver's license suspension or revocation?
No. You must have a valid, unrestricted regular driver's license before you can obtain a CDL. If your license is suspended or revoked, you cannot hold a CDL. Once your regular license is reinstated, you can then pursue a CDL.
How long does it take to get a CDL from start to finish?
The timeline varies by state and your study pace. Most people spend two to eight weeks studying for the written test, then another one to four weeks preparing for the driving test. The actual testing and processing can add another two to four weeks. Total time is typically one to four months.
Do I need to attend a truck driving school to get a CDL?
No, truck driving school is not required by law. However, many employers prefer or require it because it provides hands-on training and reduces the risk of accidents. Some states offer a reduced written test score requirement if you complete an approved training program. You can study on your own and take the tests independently, but you will need access to a commercial vehicle for the driving test.
What happens if I let my CDL expire?
If your CDL expires, you cannot legally drive a commercial vehicle. You must renew it before you can work. Renewal processes vary by state — some allow online renewal, others require an in-person visit. You may need to retake the medical exam and written test, depending on how long it has been expired and your state's rules.
Can I hold both a regular driver's license and a CDL at the same time?
No. When you obtain a CDL, your regular license is replaced by the CDL. The CDL allows you to drive both commercial and personal vehicles, so you do not need both. If your CDL is revoked or you no longer need it, you can explore for a regular license again.