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If you’re planning to drive commercial motor vehicles (CMVs) with air brakes, our Idaho DMV CDL Air Brakes Practice Tests will help you pass your Air Brakes knowledge exam on your first attempt. In Idaho, should you fail any of the knowledge tests, you must wait three business days and pay a fee before retesting. If you don’t pass, your CDL will include the restriction “L,” preventing you from operating CMVs with air brakes. In Idaho, the Rocky Mountains challenge drivers with steep inclines and declines that make air brakes essential. The mixed challenges along Idaho’s principal transportation routes (I-84, US-95, I-90, US-20) offer everything from mountain passes to the terrain in Yellowstone. Most semi-trucks, tractor-trailers, and large buses rely on air brakes, so the air brakes qualification is essential.
Industries across the Gem State rely on drivers with the air brake qualification. Key industries include agriculture, mining, and tourism (Sun Valley). Major companies requiring the air brakes qualification include Simplot Company and Idaho Milk Transport in the agriculture sector and Old Dominion Freight Line and Western Transport in the logistics sector. Commercial and public transportation are also busy industries requiring drivers with the air brake qualification. Examples are Salt Lake Express, Sun Valley Express, Valley Regional Transit, and all school districts operating full-size school buses. Simply put, the “L” restriction makes operating CMVs equipped with air brakes illegal, making these job prospects (and many more) unattainable.
M.S., Chief Educational Researcher (ACES member)
Last verified for accuracy on
Our practice tests help you pass your air brake knowledge test. But, the information you learn will also be useful as you practice inspecting and operating CMVs to pass your skills test. The hands-on skills test includes inspecting components, testing for air pressure and leaks, and operating a vehicle equipped with air brakes. The written Air Brakes knowledge test features multiple-choice questions based on the official Idaho CDL manual (Idaho CDL Handbook 2026) and requires a score of at least 80% to pass.
Our CDL Air Brakes Practice Tests cover all that is required for the official DMV knowledge test and mimic the content and format you will face on the test. Additionally, our practice test questions and answers provide responses in real time, which is a scientifically proven method for improving material retention. This feature allows you to learn quickly and confidently pass your official exam on your first attempt.
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.
