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ID CDL Air Brakes Practice Test 4 2025

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

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/.

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/.

Get started now!

Real exam-style pitfalls you’ll practice:
Common Traps
Distractors
Trick Wording
Double Negatives
ID CDL Air Brakes Practice Test 4 2025
ID commercial driver's license
Based on official ID exam questions
Steven Litvintchouk, M.S., Chief Educational Researcher at Driving-Tests.org

Authored and fact-checked by Steven Litvintchouk, M.S.

Chief Educational Researcher, Driving‑Tests.org (ACES member)
Verified for accuracy November 2025
Methodology & Editorial Policy

9 min to complete
Available in EN and ES

What to expect on the actual ID permit test

25

questions

20

correct answers to pass

80%

passing score

More ID CDL test resources

  1. Air Brakes Test 1
  2. Air Brakes Test 3
  3. Air Brakes Test 4 (you are here)

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