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Doubles & Triples

The Doubles and Triples CDL permit test preparation tools are designed to help you study for the Doubles and Triples written test you will take if you want to get a CDL to drive double or triple trailers.

The Doubles and Triples CDL permit knowledge test is for commercial drivers if you want to pull double or triple trailers.  This is an Endorsement to the CDL.

The tools below contain information you need to learn to pass the CDL knowledge test for driving safely with double and triple trailers. It tells about how important it is to be very careful when driving with more than one trailer, how to couple and uncouple correctly, and about inspecting doubles and triples carefully.

If you want to drive a commercial vehicle that pulls double or triple trailers, you must take a test on this information to get a CDL with Doubles/Triples Endorsement. These written tests are usually administered at your local DMV office.

In this course you will find two helpful tools.  Both are designed to help you learn the CDL concepts by using a “question and answer” format:

Course Content – This is another resource that is in quiz format.  Quizzes are broken into individual topics.  As you take the quizzes, you will see the correct answer.  Use the quizzes to learn important CDL concepts for the topic.

Practice Tests – Practice tests have audio available so you can listen to the questions.  You will be asked specific questions that may be on the CDL written test you will take to get your CDL permit or Endorsement. The tests give you the correct answer so that you can learn as you test.


The test questions are very similar to the questions you will see on the state CDL permit written test.

The following topics are included in Combination Vehicles:

  • Pulling Double/Triple Trailers

  • Coupling and Uncoupling

  • Inspecting Doubles and Triples

  • Checking Air Brakes

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