What a Double Endorsement Means and Why You Might Need It
A double endorsement means you hold two endorsements on a single Commercial Driver's License — for example, Hazmat (H) and Tanker (T), or Passenger (P) and School Bus (S). You do not need a separate license for each; both appear on one CDL card. The endorsements you can combine depend on your state and the specific endorsement rules, but most states allow multiple endorsements on the same license as long as you meet the requirements for each one.
You might pursue a double endorsement if your job requires you to haul hazardous materials in a tanker, or to drive both passenger buses and school buses. Some employers prefer drivers with multiple endorsements because it makes scheduling and deployment more flexible. The process involves passing the written test and, in most cases, the skills test for each endorsement separately.
The timeline and cost depend on whether you already hold one endorsement and are adding a second, or whether you are starting from scratch. If you already have a CDL with one endorsement, adding a second is usually faster than obtaining both at once.
Key Takeaways
- You must pass the written knowledge test for each endorsement you want, and most states require a separate skills test for each one as well.
- If you already hold a CDL with one endorsement, you can add a second by passing the additional tests without renewing your entire license.
- Some endorsement combinations are restricted by federal or state law — for example, you cannot hold Hazmat and School Bus together in most states.
- Each endorsement has its own fee, so a double endorsement costs more than a single one, though less than renewing your entire CDL.
- The order in which you obtain endorsements matters if one has a longer validity period than the other, because both will expire on your license expiration date.
Endorsement Combinations You Can and Cannot Hold Together
Not every endorsement pair is legal. Federal law prohibits certain combinations for safety reasons. The most common restriction is Hazmat (H) and School Bus (S) — you cannot hold both because a school bus driver transporting children cannot also be authorized to haul hazardous materials. Similarly, Passenger (P) and Hazmat (H) are restricted in most states, because a bus carrying passengers cannot carry hazmat cargo.
Allowed combinations include Hazmat and Tanker, Passenger and Tanker, School Bus and Tanker, and many others. Your state's DMV website or CDL handbook will list the specific restrictions that explore in your state. Before you invest time and money in testing, check your state's rules to confirm the pair you want is permitted.
If you hold an endorsement that later becomes incompatible with a new endorsement you want to add, you may be required to surrender the first one. This is rare but can happen if state law changes or if you move to a state with stricter rules.
Steps to Add a Second Endorsement to an Existing CDL
If you already have a CDL with one endorsement and want to add a second, follow this sequence:
- Study the knowledge test material. Obtain your state's CDL handbook and review the section for the endorsement you want to add. Most states provide the handbook free online or at the DMV office.
- Schedule your written test. Contact your state's DMV or use their online scheduling system to book a knowledge test appointment for the new endorsement. You do not need to renew your license to add an endorsement.
- Pass the written test. Take the test at your scheduled appointment. The test is usually 20 to 50 questions, depending on the endorsement. You must pass with a score of 80 percent or higher in most states.
- Schedule your skills test. Once you pass the written test, you can book a skills test appointment. Some states allow you to take the skills test on the same day as the written test if you pass; others require a separate appointment.
- Pass the skills test. The skills test includes a pre-trip inspection, basic control, and road test, all specific to the endorsement. For example, a Tanker endorsement test focuses on tank vehicle handling.
- Pay the endorsement fee. Each endorsement has a separate fee, which varies by state. Fees typically range from $10 to $50 per endorsement.
- Receive your updated CDL. Once you pass both tests and pay the fee, your state will issue a new CDL card with both endorsements printed on it. This usually takes one to two weeks by mail.
Obtaining Both Endorsements at the Same Time
If you do not yet have a CDL and want to start with two endorsements, the process is similar but you must also pass the general CDL knowledge and skills tests first. You will take the general test, then the test for each endorsement you want. This means three written tests and three skills tests in total — or more, depending on how many endorsements you pursue.
Most testing facilities allow you to schedule all tests on the same day or across consecutive days, though this is physically demanding. You must pass each test before moving to the next one; if you fail any test, you can retake it after a waiting period (usually one to seven days, depending on your state).
The total cost is higher when starting from scratch because you pay the base CDL fee plus a fee for each endorsement. In most states, this ranges from $50 to $150 total, but varies significantly. Check your state's DMV fee schedule before you begin.
Hazmat Endorsement Requirements and Background Checks
If one of your endorsements is Hazmat (H), you must complete a Transportation Security Administration (TSA) background check before you can test for or hold the endorsement. This is a federal requirement, not optional. The background check includes fingerprinting and a records review; it typically takes one to two weeks.
You must explore for the background check at your state's DMV office or through an approved third-party vendor. The fee for the TSA check is separate from the endorsement fee and usually ranges from $85 to $175. You pay this fee before the background check begins, and it is non-refundable even if you do not pass the check or decide not to pursue the endorsement.
If you are adding Hazmat to an existing CDL, you still must complete the full background check process, even though you already hold a CDL. The check is specific to the Hazmat endorsement and is required every time you renew your Hazmat endorsement as well.
School Bus Endorsement and Medical Certification
If one of your endorsements is School Bus (S), you must hold a valid medical certificate issued by a certified medical examiner. This is a federal requirement for any CDL holder who drives a school bus. The medical certificate is valid for two years and must be renewed before it expires.
You obtain the medical certificate by scheduling an appointment with a medical examiner certified by the Federal Motor Carrier Safety Administration (FMCSA). The examiner will review your health history, conduct a physical exam, and check your vision and hearing. The cost is typically $50 to $150, depending on the examiner.
If your medical certificate expires while you hold a School Bus endorsement, your endorsement becomes invalid until you renew the certificate. You can still drive with your base CDL, but you cannot legally operate a school bus. This is different from other endorsements, which remain valid as long as your CDL is valid.
Timeline and Renewal Considerations
The total time to obtain a double endorsement ranges from two weeks to two months, depending on how quickly you schedule tests and whether you pass on your first attempt. If you already hold one endorsement, adding a second typically takes three to four weeks from the day you start studying to the day your new card arrives.
When you add a second endorsement to an existing CDL, both endorsements will expire on your current CDL expiration date, not on separate dates. For example, if your CDL expires in 18 months and you add a new endorsement today, that new endorsement will also expire in 18 months, even if it would normally be valid for longer. This means you may renew both endorsements at the same time when your CDL comes due.
If one endorsement has a shorter validity period than another — for example, Hazmat is valid for five years but your CDL is valid for eight years — the shorter period controls. Your Hazmat endorsement will expire first, and you will need to renew just that endorsement before it lapses, separate from your full CDL renewal.
Common Mistakes to Avoid
The most common mistake is not checking whether your desired endorsement combination is legal in your state before you study and test. Spending time preparing for a combination that is prohibited wastes money and effort. Always verify the rules with your state's DMV before you begin.
A second frequent error is underestimating the time required for a Hazmat background check. If Hazmat is one of your endorsements, the TSA check must be completed and approved before you can take the Hazmat knowledge test. Do not schedule your test until the background check is finished and you have received approval.
Drivers also sometimes fail to renew a medical certificate before it expires when they hold a School Bus endorsement. Set a reminder six months before your medical certificate expires so you have time to schedule a renewal appointment. Your School Bus endorsement becomes invalid the moment the certificate lapses, even if your CDL is still valid.
Frequently Asked Questions
Can I hold Hazmat and School Bus endorsements at the same time?
No. Federal law prohibits this combination because a school bus carries children and cannot be used to transport hazardous materials. If you currently hold both and move to a state with stricter enforcement, you may be required to surrender one.
Do I have to retake the general CDL test if I already have a CDL and want to add an endorsement?
No. You only take the written test and skills test for the specific endorsement you are adding. Your existing CDL knowledge and skills remain valid, so you do not repeat the general tests.
What happens if I fail the skills test for one endorsement but pass the other?
You will receive only the endorsement you passed. You can retake the failed endorsement test after the waiting period (usually one to seven days). Your CDL will be issued with only the passing endorsement until you pass the second test.
Do I need a medical certificate for every endorsement, or just School Bus?
Only School Bus requires a medical certificate. Other endorsements like Hazmat, Tanker, and Passenger do not have a medical certificate requirement, though Hazmat requires a TSA background check.
If I move to a different state, do my endorsements transfer?
Your endorsements transfer when you move, but you must obtain a new CDL from your new state. Some states may have different rules about which endorsements are allowed or how they are tested. Contact your new state's DMV to confirm your endorsements will be recognized.