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 | => | 24% |
| 80-89 | => | 26% |
| 70-79 | => | 27% |
| 60-69 | => | 19% |
| <60% | => | 5% |
Planning to drive commercial motor vehicles (CMVs) equipped with air brakes? Our practice materials are just what you need for the written knowledge test. Without passing, your CDL will include the restriction “L,” indicating that you’re not allowed to drive CMVs with air brakes. That’s quite a limitation on your job prospects. (Virtually all semi-trucks and tractor-trailers are equipped with air brakes.) Therefore, preparing for this test is a very wise career choice. In fact, in Colorado, the air brakes qualification is a requirement of most companies due to the commonality of this braking system.
Organizations in Colorado that typically require drivers to have this qualification include J.B. Hunt Transport Services, Schneider National, Inc., Swift Transportation, Werner Enterprises, FedEx and UPS Freight, Old Dominion Freight Line, XPO Logistics, YRC Freight, and Estes Express Lines. Air brakes are more powerful than hydraulic brakes, so they can stop a CMV weighing up to 80,000 pounds. They also provide protective redundancy and safety. Simply put, the “L” restriction makes operating CMVs equipped with air brakes illegal, thus limiting your job prospects. So, let’s take a look at the requirements to remove the “L” and become a winner in the industry.
M.S., Chief Educational Researcher (ACES member)
Last verified for accuracy on
The official DMV test covers the parts of an air brake system, how to use them effectively, and air-brake inspection procedures. There are two parts to the test: the skills test and the knowledge test. The skills test will require you to physically inspect an air brake system, identify its components, and operate a vehicle equipped with air brakes. This test includes checking air pressure, testing the brakes for leaks, and more. The written test is in a multiple-choice format with questions on the concepts you’ve studied in the state’s CDL manual. You’ll need a score of 80% or higher to pass.
We have taken into careful consideration all that is required for the knowledge test and created Colorado DMV CDL Air Brakes Practice Tests, which mimic the content and format you will face on the official DMV test. With our practice test questions and answers provided in real time, you can learn the material quickly and feel confident as you near the day of your official exam. Once you feel prepared, simply schedule the knowledge test at the DMV, pay any fees, and take the test.
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 CO 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.
