A Class A license in Missouri lets you drive any single vehicle or combination of vehicles, as long as the total weight meets federal standards
Missouri's Class A is the highest commercial driver's license (CDL) category. It covers tractor-trailers, semi-trucks, and any combination of vehicles where the towed unit weighs 10,001 pounds or more. You can also drive anything a Class B or Class C license permits, so a Class A gives you the broadest range of commercial driving options in the state.
The weight threshold is the key dividing line. If you're pulling a trailer that weighs more than 10,000 pounds, you need at least a Class A. If the trailer weighs 10,000 pounds or less, a Class B may be sufficient. Missouri follows federal Gross Combination Weight Rating (GCWR) standards, which means the weight limits are set by the truck and trailer manufacturer, not by what the vehicle actually carries on any given day.
Key Takeaways
- A Class A CDL in Missouri covers tractor-trailers and any combination vehicle where the towed unit exceeds 10,000 pounds.
- You must pass a written knowledge test, a pre-trip vehicle inspection test, and a road test specific to Class A vehicles.
- Missouri requires you to hold a valid Class D (regular) driver's license for at least 14 days before you can test for a CDL.
- Hazardous materials (hazmat) and passenger endorsements require separate written tests and are not included with the base Class A license.
- Medical certification through a Department of Transportation (DOT) physical is required before you can obtain or renew a Class A CDL.
What vehicles you can legally operate with a Class A
With a Class A CDL, you can drive tractor-trailers (the most common use), doubles and triples (multiple trailers towed behind one tractor), and any other combination where the towed portion weighs more than 10,000 pounds. You can also drive any vehicle that requires a Class B or Class C license, so the license is stackable downward.
The practical limit is the GCWR of the specific vehicle. A manufacturer assigns a GCWR based on the truck's frame, axles, brakes, and transmission. If a truck's GCWR is 80,000 pounds and you're pulling a loaded trailer, the combined weight of the tractor, trailer, and cargo cannot exceed that rating. Exceeding it is illegal and voids your insurance.
You cannot drive a school bus, a bus carrying passengers for hire, or a vehicle carrying hazardous materials unless you obtain the appropriate endorsement. These endorsements require additional written tests and, in some cases, additional road tests.
Testing requirements to obtain a Class A in Missouri
Missouri requires three separate tests: a written knowledge test, a pre-trip inspection test, and a road test. All three must be passed before the state issues your Class A CDL.
The written knowledge test covers vehicle operation, safety, weight and balance, braking systems, and federal regulations. You answer 50 questions and must score at least 80 percent. The test is offered at Missouri Department of Revenue (DOR) driver license offices. You can study using the Missouri CDL manual, which the state publishes free online.
The pre-trip inspection test requires you to walk around a Class A vehicle (usually a tractor-trailer provided by the testing facility or your training school) and identify components, explain their function, and demonstrate that they work. You must show you can check brakes, lights, coupling devices, tires, and safety equipment. This test is pass-or-fail and is typically administered by a third-party examiner certified by Missouri.
The road test takes place in an actual Class A vehicle on public roads or a closed course. You perform basic maneuvers (backing, turning, lane changes), highway driving, and emergency stops. The examiner watches for safe handling, proper use of mirrors, smooth braking, and compliance with traffic laws. This test lasts roughly 30 to 45 minutes.
Medical certification and the DOT physical
Before Missouri will issue a Class A CDL, you must pass a Department of Transportation (DOT) physical examination. This is not the same as a regular doctor's visit. A DOT-certified medical examiner checks your vision, hearing, blood pressure, and ability to operate a commercial vehicle safely. They also review your medical history for conditions that might affect driving, such as diabetes, heart disease, or sleep apnea.
If you pass, the examiner issues a Medical Certificate (Form MCSA-5875), which is valid for two years. You must carry this certificate with you when you drive. If you fail, you may be able to obtain a conditional certificate if your condition can be managed, but this requires documentation from your own physician.
The cost of a DOT physical varies by provider but typically ranges from $100 to $200. Some employers cover this cost for new hires; others require the driver to pay. You can find DOT-certified examiners through the Federal Motor Carrier Safety Administration (FMCSA) website or by asking your training school or employer for a referral.
Prerequisites and waiting periods before you can test
You must hold a valid Missouri Class D (regular) driver's license for at least 14 days before you can take any CDL test. This means you cannot walk into a driver license office, pass the CDL tests, and leave with a Class A on the same day. The 14-day holding period is a state requirement designed to may support you have recent driving experience.
If you already hold a valid out-of-state CDL, Missouri may waive some testing requirements, but you still must explore for a Missouri CDL and provide proof of your current license. The process is faster than starting from scratch, but you cannot straightforward transfer an out-of-state CDL.
You must also be at least 18 years old to obtain a Class A CDL in Missouri. If you are 18 to 20, you can drive within Missouri but cannot cross state lines; federal law restricts interstate commerce driving to those 21 and older.
Endorsements and restrictions that explore to Class A
A base Class A CDL does not include the right to carry hazardous materials or to drive a passenger bus. If your job requires either, you must pass an additional written test for that endorsement. The hazmat endorsement (H) requires a written test covering hazardous materials regulations, placarding, and emergency procedures. The passenger endorsement (P) requires a test on passenger safety and vehicle operation with passengers aboard.
Some Class A drivers also obtain a tanker endorsement (N) if they haul liquids in tank trailers. Each endorsement is a separate test and costs an additional fee. Missouri charges roughly $10 to $15 per endorsement, though fees can change.
Restrictions may be placed on your Class A if you fail certain parts of the road test or if you have medical conditions that require monitoring. For example, if you fail the air brake component of the road test, your license may carry an air brake restriction, meaning you cannot drive vehicles with air brakes. Restrictions are noted on your CDL card.
How long a Class A CDL is valid in Missouri
A Class A CDL in Missouri is valid for five years from the date of issue. Your renewal date is printed on the front of your CDL card. You must renew before the expiration date to continue driving commercially.
When you renew, you must pass a new DOT physical and provide an updated Medical Certificate. You do not have to retake the written or road tests unless your license was suspended, revoked, or expired for more than one year. If your license expired more than one year ago, you must retest as if you were obtaining a new CDL.
You can renew your Class A CDL at any Missouri Department of Revenue driver license office. Some offices allow online renewal for the administrative portion, but you must visit in person to provide your Medical Certificate and have your photo updated.
Frequently Asked Questions
Can I get a Class A CDL if I have a DWI or traffic violation on my record?
A DWI does not automatically disqualify you, but it will be reviewed during your process. Missouri and the federal government look at the severity, how recent it was, and whether it involved a commercial vehicle. Some violations may result in denial or a waiting period. Contact your local Missouri Department of Revenue office to discuss your specific situation.
What is the difference between a Class A and a Class B CDL in Missouri?
A Class B CDL covers single vehicles or combinations where the towed unit weighs 10,000 pounds or less. A Class A covers any combination where the towed unit weighs more than 10,000 pounds. Class A is broader and allows you to drive anything a Class B permits, but Class B is sufficient for many commercial driving jobs that do not involve heavy trailers.
Do I need a Class A CDL to drive a pickup truck with a trailer for personal use?
No. A Class A CDL is required only for commercial driving. If you are towing a personal trailer for your own use (not for business or compensation), you use your regular Class D license. The weight limits for personal towing depend on your vehicle's specifications and Missouri law, but a CDL is not required.
How much does it cost to obtain a Class A CDL in Missouri?
Missouri charges roughly $50 to $75 for the CDL itself, plus the cost of the DOT physical (typically $100 to $200) and any training or testing fees charged by a third-party examiner or school. Total out-of-pocket cost usually ranges from $200 to $500, depending on whether you use a training school and how many tests you need to retake.
Can I switch from a Class A CDL to a regular Class D license?
Yes. You can downgrade to a Class D at any time by visiting a Missouri Department of Revenue office and requesting the change. Your CDL will be replaced with a regular driver's license. You do not need to retake any tests; the downgrade is administrative.