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Before you can operate commercial motor vehicles (CMVs) equipped with air brakes on Idaho’s highways, you must pass the CDL Air Brakes Knowledge Test and the Skills Test (in a vehicle equipped with air brakes). Without passing, you cannot legally operate vehicles equipped with air brakes; your CDL will bear the “L” restriction that limits you to non–air brake vehicles. And to be clear, the majority of CMVs, including tractor-trailers and combination vehicles, are equipped with air brakes. Even most large school buses come with air brakes, so you’re really shooting yourself in the foot without this qualification, as the door to a vast majority of opportunities will remain closed to you.
The Idaho DMV CDL Air Brakes Knowledge Test contains 20 multiple-choice questions, at least 16 of which you must answer correctly (a minimum score of 80%) to pass. If you don’t pass, state rules require a minimum one-business-day wait before retesting, along with a small retest fee. Fortunately, our free Idaho CDL Air Brakes Practice Tests mirror the real exam, offer immediate feedback and study hints as needed, and provide clear explanations to help you master the material before test day. Once you’ve aced this practice test, try another here: https://driving-tests.org/idaho/id-cdl-air-brake-practice-test/.
M.S., Chief Educational Researcher (ACES member)
Last verified for accuracy on
You’ll also need to pass the Skills Test, which involves an on-the-road vehicle inspection, checking for leaks, air pressure checks, and demonstrating safe operation of an air brake-equipped vehicle. Whether you’re hauling timber from the Panhandle, livestock from the Magic Valley, or construction materials along Interstate 84, proving mastery of air brakes is a necessary first step.
Major industries in the Gem State that depend on air brake-qualified drivers include agriculture, forestry, food processing, construction, and long-haul logistics. Major employers like Challenger Pallet & Supply, FedEx Freight, Lamb Weston, and Swift Transportation often hire air brake-qualified drivers. Simply put, the air brake qualification opens doors to many of these job opportunities.
While you’re at it, you should consider studying for the CDL Combination Vehicles Knowledge Test, which is one of the requirements for a Class A License. This license type will add tremendous versatility (and job opportunities) to your CDL: https://driving-tests.org/idaho/id-cdl-combination-test/. Also, adding Idaho endorsements to your CDL is another great way to open additional employment opportunities. Try one of our Endorsement Practice Tests here: https://driving-tests.org/idaho/id-cdl-hazmat-practice-test/.
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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 ID 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.
