What endorsements are and why you need them

An endorsement is a notation on your Colorado driver's license that says you are legally permitted to operate a specific type of vehicle or perform a specific driving task. Without the right endorsement, you cannot legally do that work — even if you own the vehicle or have years of experience driving it.

Endorsements are different from restrictions. A restriction limits what you can do (like "corrective lenses required"). An endorsement adds permission. You may need one endorsement, several, or none, depending on what you drive and what you haul.

Colorado issues endorsements only to holders of a Commercial Driver's License (CDL). If you hold a regular Class D license, you do not need endorsements for the vehicles and cargo you are legally allowed to drive in Colorado. This guide covers CDL endorsements only.

Key Takeaways

  • Colorado CDL endorsements are added to your license to permit you to drive specific vehicle types or transport specific cargo, and you cannot legally do these tasks without them.
  • The main endorsements are H (hazardous materials), T (double/triple trailers), P (passenger), and N (tank vehicles), and you may hold more than one at the same time.
  • To add an endorsement, you must pass a written test specific to that endorsement at a Colorado Division of Motor Vehicles office.
  • You do not need a road test to add an endorsement to an existing CDL, only the written test for that endorsement.
  • Endorsement tests cover the rules, safety procedures, and regulations for that specific vehicle type or cargo, and study materials are available from the Colorado DMV.

The four main Colorado CDL endorsements

H (Hazardous Materials) allows you to transport hazardous materials — explosives, flammable liquids, gases, poisons, radioactive materials, and other regulated substances. This is the most commonly required endorsement. You must pass a written test and undergo a federal background check. The H endorsement must be renewed every five years.

T (Double/Triple Trailers) allows you to tow two or three trailers at the same time. Without this endorsement, you can tow only one trailer. You must pass a written test covering coupling procedures, weight distribution, and safe operation of multiple trailers.

P (Passenger) allows you to operate a vehicle designed to carry 16 or more passengers, including the driver. This includes buses and large vans. You must pass a written test covering passenger safety, loading procedures, and emergency evacuation.

N (Tank Vehicles) allows you to operate a vehicle with a cargo tank designed to carry liquids or gases in bulk — tanker trucks, for example. You must pass a written test covering tank vehicle operation, weight distribution, and safe handling of liquid cargo.

You can hold multiple endorsements on the same license. For example, a hazmat tanker driver would hold both H and N endorsements. Each endorsement requires its own written test.

How to add an endorsement to your Colorado CDL

Visit your local Colorado Division of Motor Vehicles office in person. You cannot add an endorsement by mail or online. Bring your current CDL, proof of Colorado residency, and your Social Security number or Individual Taxpayer Identification Number.

Tell the DMV staff which endorsement you want to add. They will give you the written test for that endorsement. The test is multiple choice and covers the rules, safety procedures, and regulations specific to that endorsement. You must score at least 80 percent to pass.

If you pass, the DMV will issue you a new CDL with the endorsement added. There is no road test required to add an endorsement — only the written test. If you do not pass, you can retake the test. There is no waiting period between attempts, but you may need to pay a fee each time you test.

The fee for adding an endorsement varies. Contact your local DMV office for the current cost.

Study materials and test preparation

The Colorado DMV publishes a CDL manual that covers all endorsement topics. You can read it free from the Colorado Department of Revenue website or pick up a printed copy at any DMV office. The manual includes sample test questions for each endorsement.

The H endorsement (hazardous materials) requires additional study because it involves federal regulations. The manual covers the hazmat rules you need to know. Many drivers also study the Federal Motor Carrier Safety Administration (FMCSA) hazmat regulations online.

The T, P, and N endorsements are covered in the Colorado CDL manual. Read the sections that explore to the endorsement you are testing for. The written test will ask questions directly from the material in the manual.

Renewing and maintaining your endorsements

Most endorsements are valid for the same period as your CDL — typically five years in Colorado. The H (hazardous materials) endorsement must be renewed every five years and requires a federal background check each time.

When your CDL expires, all endorsements expire with it. To renew your CDL, you must visit a DMV office in person. If you want to keep an endorsement, you do not need to retake the endorsement test — the endorsement will renew automatically as long as you renew your CDL on time.

If your CDL expires and you do not renew it within a certain period, you may lose your endorsements. Contact your local DMV office to learn the exact timeline for your situation.

Removing or changing endorsements

You can request to have an endorsement removed from your license at any time. Visit a Colorado DMV office and ask to have the endorsement removed. There is no test required — the DMV will straightforward issue you a new CDL without that endorsement.

You might remove an endorsement if you no longer need it for your job, or if you want to simplify your license. Removing an endorsement does not affect your CDL itself or any other endorsements you hold.

If you want to add a different endorsement later, you can do so by taking the written test for that endorsement.

Frequently Asked Questions

Can I add an endorsement if my CDL is suspended or revoked?

No. You must have a valid, active CDL to add an endorsement. If your CDL is suspended or revoked, you cannot test for or receive a new endorsement until your CDL is reinstated.

Do I need to pass a road test to add an endorsement?

No. You only need to pass the written test for that endorsement. The road test is required only when you first obtain your CDL, not when you add endorsements to an existing CDL.

What happens if I fail the endorsement test?

You can retake the test. There is no waiting period between attempts in most cases, but you may be charged a fee each time you test. Ask your DMV office about retesting fees and procedures.

Can I hold more than one endorsement at the same time?

Yes. You can hold as many endorsements as you need. For example, a driver who transports hazmat in a tanker truck would have both H and N endorsements on the same license.

How long does it take to get an endorsement added to my license?

If you pass the test, the DMV will issue your new CDL with the endorsement the same day or within a few days, depending on your local office. If you fail, you can retake the test at your next visit.