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If you’re looking to add the Double/Triple Trailers endorsement to your Illinois Commercial Driver’s License (CDL,) you’re probably aware that the main hurdle 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 the valuable “T” endorsement on your CDL, which authorizes you to pull two or three trailers (where such laws allow) and operate combination vehicles that require this added skill and knowledge (Illinois CDL Handbook 2026).
In “The Prairie State” even with a Double/Triple Trailers endorsement, you’re only allowed to pull double trailers and the length of any cargo cannot exceed sixty feet by state law. But, make no mistake, this endorsement adds significant credibility and marketability to your transport status, increasing your employability and earning potential. You may be saying to yourself, “This sounds incredible! But how can I best prepare for the test?”
You will find no shortage of online resources, but too much information can be incredibly overwhelming. What you need is a systematic and focused approach. That’s where our online Illinois CDL Double/Triple Trailers practice test comes in. It is up to date as of January 2026 and includes 20 multiple-choice questions that resemble what you will face at the DMV on your actual test day!
M.S., Chief Educational Researcher (ACES member)
Last verified for accuracy on
As you take our online practice test, you will receive immediate and detailed feedback on your answers. If you get a question wrong, you are immediately shown why a different response is correct. This helps solidify the content in real time, instead of bombarding you with the entire assessment at the end.
Illinois 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, after passing the test, pay the required fee to add the endorsement to your CDL.
Looking for other Illinois-based CDL endorsements? Find tons of valuable information and practice tests here.
Interested in CDL endorsements for another state? We have you covered there as well! Browse our site and click CDL to select your choice of state.
Driver’s Ed is - nobody wants to set foot inside the DMV. That’s why millions of learners trust us for simple, visual, effective prep.
We are an officially recognized FMCSA Entry-Level Driver Training provider and a proud partner to over 2,500 libraries. We work with safety organizations like GHSA and the National Safety Council to help create safer roads for everyone.
Our trademarked system automatically saves questions you miss, creating personalized tests that target your weak spots until you’ve mastered the material.
Get smarter as you study. Our new AI-powered feedback provides detailed, question-level insights to help you understand the why behind each answer.
Go beyond the boring black-and-white manual. Our interactive handbook lets you read, listen with an MP3 audio version, or even chat with it to find the information you need, faster.
We build our practice questions from the current 2026 IL Driver Handbook and refine them using patterns recent test‑takers report.
Driver handbook • Knowledge‑test/permit overview • Fees & ID requirements • Office/appointment info
We mirror recurring themes (e.g., right‑of‑way traps, sign look‑alikes) and use similar distractors and wording styles.
We don’t collect or publish actual test items and we’re not affiliated with DMV.
