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  • Updated for January 2025
  • Based on 2025 CO commercial driver's license manual

Free CO CDL Double/Triple Trailers Practice Test 2025

Did you know that in Colorado you cannot tow more than one trailer or vehicle unless it’s for commercial purposes and you have obtained the Double/Triple Trailers endorsement? If you’re looking to add this endorsement on your Colorado Commercial Driver’s License (CDL), the key requirement is passing a 20-question multiple-choice knowledge test. The test requires a score of 80% (or 16 correct answers) to pass. Once you’ve achieved this certification, you receive a “T” endorsement on your CDL, which authorizes you to pull two or three trailers (where legal) and operate combination vehicles that require this added skill and knowledge (Colorado CDL Handbook 2025).

This endorsement covers double pup trailers, which are legal throughout the United States. Adding this credential significantly enhances your CDL, making you capable of transporting more freight and immediately more marketable in the industry. Goods that are often shipped by way of double trailers in Colorado include agricultural products, industrial goods, consumer goods, and Colorado’s natural resources like coal and timber. You may be saying to yourself, “That sounds incredible! But how can I best prepare for this test?”

There is an abundance of online resources, but too much information can be overwhelming. What you need is a clear and systematic approach, which is where our online Colorado CDL Double/Triple Trailers practice test comes in. It is up to date as of January 2025 and includes 20 multiple-choice questions that resemble what you will face at the DMV on your actual test day!

As you work through our online practice test, you’ll receive instant and detailed feedback on your answers. If you make a mistake, you’ll immediately see the correct answer along with a clear explanation of why it is the better choice. This method reinforces the material in real-time, instead of bombarding you with the entire assessment at the end.

Colorado only requires the passing of this knowledge test in order to add the “T” endorsement to your already existing Class A or Class B CDL. Once you have prepared, passed our free practice tests, and feel ready to go, you simply apply at the DMV, provide the required documentation, and pay the fee prior to taking the official test.

Looking for other Colorado-based CDL endorsements? Find tons of valuable information and practice tests here.

  • Perfect for first-time and renewal CDL/CLP applicants, and those adding endorsements

What you need to know

6 min to complete
Available in EN and ES
Verified by Steven Litvintchouk, M.S., Chief Educational Researcher, Member of ACES. See our detailed commitment to accuracy and quality in our practice tests.

What to expect on the actual CO DMV exam

20

questions

16

correct answers to pass

80%

passing score

List of questions (classic view)

  1. When you're pulling more than one trailer, which trailer should be the first one behind the tractor?
  2. Which of these statements about quick steering movements and doubles/triples is true?
  3. You are driving a 100-foot double trailer combination at 50 mph. The road is dry and visibility is good. You should keep at least ____ seconds of space ahead of you.
  4. Before connecting a converter dolly to a second or third trailer, you should check the height of the trailer. The trailer height is right if
  5. You are driving a 100-foot double trailer combination at 30 mph. The road is dry and visibility is good. You should keep at least ____ seconds of space ahead of you.
  6. With the hand valve on, you should test the trailer brakes by opening the service line valve at the rear of the rig. When you do this, you should hear
  7. Empty trucks
  8. Which of these statements about handling doubles and triples is true?
  9. Before you can supply air to the air tanks of a second trailer, you need to
  10. You are driving with double trailers and must use your brakes to avoid a crash. For emergency braking, you should
  11. How can you be sure that you supplied air to a second trailer?
  12. What is likely to happen if the pintle hook is unlocked while the dolly is still under the second trailer?
  13. You want to hook your combination to a second trailer that does not have spring brakes. To do this without wheel chocks, you should
  14. Which of these statements about managing space to the sides is true?
  15. The crack-the-whip effect that troubles trucks with trailers is most likely to tip over
  16. You are visually checking the coupling of a converter dolly to the rear trailer. How much space should there be between the upper and lower fifth wheel?
  17. You are pulling doubles. A set of trailer wheels goes into a skid. Which of the following is most likely to occur?
  18. You are doing a walk-around inspection of a double or triple trailer rig. You should be sure that the converter dolly air tank drain valves are ______ and the pintle hook is _______.
  19. A converter dolly is
  20. A converter dolly consists of a ______ wheel and ________ axles.
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