What You Can and Cannot Drive With a Class B CDL

A Class B CDL lets you drive certain large vehicles, but not combination trucks

A Class B Commercial Driver's License authorizes you to operate single heavy vehicles — typically those with a gross vehicle weight rating (GVWR) of 26,001 pounds or more — but not tractor-trailers or other vehicle combinations. The most common Class B vehicles are city buses, dump trucks, cement mixers, and box trucks over a certain size. You cannot pull a trailer with a Class B; if you need to do that, you need a Class A instead.

Every state issues Class B licenses, though the specific vehicles allowed and the testing process vary slightly by state. The federal government sets minimum standards through the Commercial Driver's License (CDL) program, but your state's Department of Motor Vehicles (DMV) or equivalent agency handles the actual licensing, testing, and renewal.

Key Takeaways

A Class B CDL covers single heavy vehicles over 26,001 pounds GVWR but excludes any vehicle combination, including tractor-trailers and straight trucks towing trailers.
You must pass a written knowledge test, a skills test (pre-trip inspection, basic vehicle control, and road test), and a medical examination to obtain a Class B.
Most states require you to hold a regular driver's license first and meet a minimum age requirement, usually 18 for intrastate driving and 21 for interstate.
Endorsements such as Passenger (P) or Tank (T) add specific permissions to your Class B and require additional testing.
Your Class B must be renewed every four to eight years depending on your state, and you must pass a medical exam at each renewal.

What vehicles you can drive with a Class B

A Class B CDL covers any single vehicle — meaning no trailer attached — that weighs 26,001 pounds or more GVWR. This includes city buses, school buses (with a Passenger endorsement), dump trucks, concrete mixers, box trucks, and straight trucks used for delivery or hauling. The key word is single: the vehicle itself is heavy, but nothing is towed behind it.

You can also drive any vehicle lighter than 26,001 pounds with a Class B, so the license covers smaller commercial trucks as well. However, the moment you attach a trailer — even a small one — you move into Class A territory and need a different license. Some states allow Class B drivers to tow a trailer under certain weight thresholds with specific endorsements, so check your state's rules before assuming you cannot tow anything.

What vehicles you cannot drive with a Class B

You cannot operate any combination vehicle — a tractor pulling a trailer, a straight truck with a trailer, or any other multi-unit setup. This is the defining limit of Class B. If your job involves pulling a trailer of any kind, you need a Class A CDL instead. You also cannot drive certain hazardous materials vehicles or passenger vehicles carrying more than 15 people without the appropriate endorsements, even if they are single units.

Some states restrict Class B drivers from operating certain specialized vehicles like double or triple trailers, or from carrying passengers in numbers that require a Passenger endorsement. Your state's CDL handbook will list the exact restrictions; review it before accepting a job that involves any towing or specialized cargo.

Testing requirements for a Class B CDL

To obtain a Class B, you must pass three separate tests administered by your state's DMV. The first is a written knowledge test covering federal and state CDL rules, vehicle safety, and safe driving practices. You study from your state's CDL manual, which is free and available online or at the DMV. Most states allow you to take this test multiple times if you fail.

The second test is the skills test, which has three parts: a pre-trip vehicle inspection (you walk around and point out safety features and check for damage), basic vehicle control (backing, parking, and maneuvering in a closed course), and a road test (driving on public roads with an examiner). You must bring a vehicle of the class you are testing for — you cannot test in a car and expect to drive a bus. The road test typically lasts 30 to 60 minutes and covers acceleration, braking, turning, lane changes, and highway driving.

The third requirement is a medical examination by a certified medical examiner. You must meet federal health standards: your vision, hearing, blood pressure, and overall fitness to drive must fall within acceptable ranges. The examiner issues a Medical Certificate valid for two years (or one year in some cases), and you must carry it with your license.

Endorsements that add permissions to your Class B

An endorsement is an add-on to your CDL that permits you to drive or carry specific cargo or passengers. The most common endorsements for Class B drivers are Passenger (P), which allows you to carry more than 15 passengers, and Tank (T), which allows you to haul liquids in tank vehicles. Other endorsements include Hazmat (H) for hazardous materials, School Bus (S), and Doubles/Triples (doubles are two trailers, triples are three — though these are rare for Class B).

Each endorsement requires a separate written test and, in some cases, an additional skills test. For example, the Passenger endorsement requires you to pass a written test on passenger safety and vehicle operation, and some states require a road test as well. Hazmat requires a written test and a background check. You can hold multiple endorsements on one Class B license. Check your state's CDL handbook to see which endorsements are available and what each one requires.

Age, residency, and medical requirements

You must be at least 18 years old to hold a Class B CDL for intrastate driving (within your state only). If you want to drive interstate (across state lines), you must be at least 21. You must also hold a valid regular driver's license (Class D or equivalent) before you can obtain a CDL. Some states require you to be a resident or have a valid state ID; check your DMV's website for your state's specific rules.

The medical examination is non-negotiable. You must pass it to obtain your license and again at each renewal. If you have a medical condition — diabetes, heart disease, sleep apnea, or certain medications — you may still be able to obtain a CDL, but you may need additional documentation or restrictions on your license. A certified medical examiner, not your personal doctor, must conduct the exam. The cost varies by state and examiner, typically between $50 and $150.

Renewal, expiration, and maintaining your Class B

A Class B CDL is valid for four to eight years depending on your state and age. Your license will show an expiration date. You must renew before that date expires; driving on an expired license is illegal. Most states allow you to renew online, by mail, or in person at the DMV, though some require an in-person visit. You will need to pass the medical exam again at renewal; if you fail, your license will not be renewed until you pass.

You do not have to retake the written or skills tests at renewal unless your state requires it or your license was suspended or revoked. However, if your license has been suspended or revoked, you must retake all tests and meet any other conditions before you can obtain a new one. Keep your Medical Certificate current; if it expires, your CDL is no longer valid for commercial driving, even if the license itself has not expired.

Frequently Asked Questions

Can I tow a trailer with a Class B CDL?

Not in most states. A Class B is for single vehicles only. If you need to tow any trailer, you need a Class A CDL. Some states may allow towing a small trailer under specific weight limits with certain endorsements, so check your state's CDL handbook or contact your DMV to be sure.

What is the difference between a Class A and Class B CDL?

A Class A covers any single vehicle plus any trailer combination. A Class B covers single heavy vehicles only — no trailers. If your job involves towing, you need Class A. Class A requires the same tests as Class B but includes additional questions about combination vehicles.

Do I need a Class B CDL to drive a school bus?

Yes, you need a Class B CDL with a School Bus (S) endorsement. You must pass the Class B tests plus a written test for the School Bus endorsement. Some states also require a road test specific to school bus operation.

How long does it take to get a Class B CDL?

The timeline depends on how quickly you study and schedule tests. The written test can be taken within days of explore. The skills test typically requires a scheduled appointment, which may be weeks out depending on your state's DMV workload. Most people complete the process in two to four weeks if they study beforehand.

What happens if I fail the skills test?

You can retake it. Most states allow you to schedule another test within a few days or weeks. You pay the test fee again. There is no limit on how many times you can retake it, though some states may require you to wait a certain number of days between attempts.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.