A BX endorsement lets you drive a Class B vehicle with air brakes in Michigan
A BX endorsement is a restriction code that appears on your Michigan driver's license when you pass the air brake knowledge test but do not pass the full commercial driver's license (CDL) exam. It means you can operate a Class B vehicle — typically a straight truck or bus — but only if that vehicle is equipped with air brakes. Without this endorsement, you cannot legally drive any air brake vehicle in that class, even if you are otherwise licensed to drive it.
The endorsement exists because air brake systems require specific knowledge and handling. Michigan's Secretary of State requires drivers to demonstrate understanding of how air brakes work, how to inspect them, and how to operate them safely before allowing operation. The BX code on your license is the state's record that you have passed that test.
This is different from a full CDL, which requires a more comprehensive exam and allows you to drive commercial vehicles across state lines and carry certain cargo. A BX endorsement is narrower — it is tied to a specific vehicle type and brake system, and it does not make you a commercial driver in the federal sense.
Key Takeaways
- A BX endorsement on your Michigan license means you passed the air brake test and can drive Class B vehicles with air brakes only.
- You get a BX endorsement by passing the air brake knowledge test at a Secretary of State office, not by obtaining a full CDL.
- Without a BX endorsement, you cannot legally operate any air brake vehicle in Michigan, even if you hold a regular driver's license for that vehicle class.
- A BX endorsement is not the same as a CDL and does not allow interstate commercial driving or the operation of certain regulated cargo.
How you get a BX endorsement in Michigan
To obtain a BX endorsement, you must visit a Secretary of State office and pass the air brake knowledge test. The test covers air brake system components, inspection procedures, operation under different road conditions, and emergency stopping. You do not need to hold a CDL or any other special license beforehand — you only need a valid Michigan driver's license for the class of vehicle you intend to drive.
The test is written and administered at the office. You will answer questions about how air brakes function, what warning signs indicate a problem, and how to respond to brake failure. The passing score is typically 80 percent, though you should confirm the current requirement when you schedule your test, as standards can change.
Once you pass, the Secretary of State adds the BX code to your license record. You do not receive a separate document — the endorsement appears on your license itself and in the state's database. If you fail the test, you can retake it, usually after a waiting period of a few days.
What vehicles you can and cannot drive with a BX endorsement
With a BX endorsement, you can drive a Class B vehicle that has air brakes. A Class B vehicle is typically a straight truck with a gross vehicle weight rating (GVWR) over 26,001 pounds, or a bus designed to carry more than 15 passengers. The key restriction is the air brake requirement — the vehicle must have air brakes for you to operate it legally under your BX endorsement.
You cannot drive a Class B vehicle with hydraulic brakes using only a BX endorsement. You also cannot drive a Class A vehicle (tractor-trailer) or Class C vehicle (smaller truck or van) under a BX endorsement, even if those vehicles have air brakes. The endorsement is specific to both the vehicle class and the brake type.
If you want to drive air brake vehicles in other classes, or if you want to drive Class B vehicles without air brakes, you will need different licensing. A full CDL with an air brake restriction (noted differently on your license) would allow broader operation, but it requires passing additional tests beyond the air brake exam.
When employers or situations require a BX endorsement
Some employers require a BX endorsement for specific jobs, particularly in school transportation, municipal services, or small trucking operations. A school district that operates buses with air brakes may require drivers to hold a BX endorsement as a condition of employment. Similarly, a city or county that maintains a fleet of garbage trucks or other Class B vehicles with air brakes may require the endorsement for those positions.
Private employers are not required to hire only drivers with a BX endorsement, but they may choose to do so if their fleet uses air brake vehicles. If you are hired for such a role, your employer will typically tell you during the hiring process that the endorsement is required and may give you a important date to obtain it.
You may also encounter situations where you need a BX endorsement if you plan to operate a vehicle you own or lease. If you own a Class B truck with air brakes and want to drive it yourself, Michigan law requires you to hold the endorsement.
The difference between a BX endorsement and a CDL
A BX endorsement and a commercial driver's license (CDL) are not the same thing. A BX endorsement is a restriction code added to a regular driver's license — it does not make you a commercial driver. A CDL is a separate, higher-level license that federal law requires for certain commercial driving roles and allows interstate operation of commercial vehicles.
To obtain a CDL in Michigan, you must pass a written knowledge test, a skills test (pre-trip inspection, basic control, and road test), and a medical examination. A BX endorsement requires only the written air brake test. A CDL allows you to drive larger vehicles, carry regulated cargo, and operate across state lines. A BX endorsement does not.
Some people obtain a BX endorsement first, then later pursue a CDL if their job or circumstances change. Others go straight to a CDL if they know they will need broader driving authority. The choice depends on your current job requirements and your long-term plans.
Renewing or updating a BX endorsement
A BX endorsement stays on your license as long as your license is valid. When you renew your Michigan driver's license, the endorsement renews with it — you do not need to retake the air brake test unless the Secretary of State specifically requires it as part of a renewal process, which is rare.
If your license is suspended, revoked, or downgraded, your BX endorsement may be affected. If you lose your license and later regain it, you may need to reapply for the endorsement, depending on the reason for the suspension or revocation. Contact your local Secretary of State office to confirm your status if your license has been suspended or revoked.
If you move to another state, your BX endorsement does not transfer. You would need to obtain the equivalent endorsement in your new state if you want to continue driving air brake vehicles there. Each state has its own licensing and endorsement requirements.
Frequently Asked Questions
Do I need a BX endorsement to drive a bus with air brakes?
Yes, if the bus is a Class B vehicle. However, if the bus is designed to carry more than 15 passengers, you may also need a passenger endorsement (P) in addition to the BX. Check with the Secretary of State about the specific requirements for the bus you will be driving.
Can I get a BX endorsement without a regular driver's license?
No. You must hold a valid Michigan driver's license for the appropriate class before you can add a BX endorsement. The endorsement is added to your existing license, not issued separately.
What happens if I drive an air brake vehicle without a BX endorsement?
You are operating the vehicle illegally and can be cited by law enforcement. The violation can result in fines and may affect your driving record. If you are involved in an accident, your insurance may deny a claim if you were not properly licensed for the vehicle.
How long does it take to get a BX endorsement after I pass the test?
The endorsement is usually added to your license record when ready after you pass the test at the Secretary of State office. Your physical license will reflect the endorsement when you renew it or request a replacement, though your record is updated right away.
Can I take the BX air brake test online?
No. The air brake knowledge test must be taken in person at a Michigan Secretary of State office. You cannot take it online or by mail. Schedule an appointment at your local office to take the test.