All your missed questions are saved
automatically for extra practice.
It's a practice test that's automatically made up of all your missed questions. Once you finish this test, you’ll be able to revisit your Challenge Bank™ to practice and sharpen your skills.
View All PlansAdding difficult questions to Challenge Bank™ is an exclusive Premium feature. Unlock access to 650+ exam-like questions, a Pass Guarantee, personalized study plans, and more.
View All Plans| 90-100 | => | 0% |
| 80-89 | => | 50% |
| 70-79 | => | 50% |
| 60-69 | => | 0% |
| <60% | => | 0% |
If you’re ready to take the next step in your trucking career in Iowa, passing the DOT Air Brakes Knowledge Test is vital to your Commercial Driver’s License (CDL). Until you pass this test and the skills test in an air brake-equipped vehicle, your CDL will retain an “L” restriction that limits you to vehicles without air brakes. This may sound like a minor point, but the majority of CMVs are equipped with air brakes. Not having this qualification severely limits your legal driving capabilities. Passing these tests is required before you can legally drive commercial motor vehicles (CMVs) equipped with air brakes. The knowledge test includes 25 multiple-choice questions, and you must score at least 80% to pass. If you miss more than four questions, you’ll need to wait at least one business day and pay a retest fee before trying again. Our series of Iowa Air Brakes Practice Tests ensures you are fully prepared and ready to pass the official exam on your first attempt.
Our practice tests are based on the Iowa CDL Manual and mirror the official exam format. You’ll cover essential knowledge like air-brake safety, inspection procedures, and air pressure systems. They include instant AI-powered feedback, helpful hints, and our Challenge Bank. This feature remembers the questions you miss and poses them again, ensuring you learn all the necessary parts for the exam. Be sure to check out another practice test once you have learned this one: https://driving-tests.org/iowa/ia-cdl-air-brake-practice-test/.
M.S., Chief Educational Researcher (ACES member)
Last verified for accuracy on
Earning your air brakes qualification opens the door to much broader transport options in Iowa’s essential industries like agriculture, manufacturing, logistics, and food transport. Major trucking corridors such as I-80, I-35, and I-29 connect key cities like Des Moines, Cedar Rapids, Davenport, Council Bluffs, and Sioux City, making the state a vital hub for freight movement across the Midwest. From hauling corn and soybeans to delivering products for major employers like CRST, Fareway, FedEx Freight, Hy-Vee, and Tyson Foods, air brake-qualified drivers keep Iowa moving.
You should also consider standing out to employers by adding endorsements like (N) Tanker, (H) Hazardous Materials, and (T) Doubles/Triples. We have Iowa Practice Tests to help you prepare for these knowledge tests as well. Check out one here: https://driving-tests.org/iowa/ia-cdl-hazmat-practice-test/. Furthermore, since most combination vehicles use air brakes, we recommend preparing for the Combination Vehicles Knowledge Test. Passing this test is one of the major requirements for a Class A CDL. Check out our series of practice tests here: https://driving-tests.org/iowa/ia-cdl-combination-test/.
Driver’s Ed is - nobody wants to set foot inside the DOT. 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 IA 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 DOT.
