CA CDL Air Brakes Practice Test 4 2025

From the Sierra Nevada and Tehachapi Mountains to the challenges of Highway 1 and the state’s crowded interstates (I-5 and I-405), getting your California Commercial Driver’s License (CDL) is a great career choice (but only if you’ve tested to remove the air brakes restriction!). Removing the air brakes restriction is one of the most important steps toward becoming a fully qualified commercial driver. You’ll need to pass both the DMV CDL Air Brakes Knowledge Test and a Skills Test in a vehicle with air brakes. If you fail either of them, your CDL will include an “L” restriction, which will legally bar you from operating any commercial motor vehicle (CMV) equipped with air brakes. Since nearly all semi-trucks, full-size buses, and large trailers use air brakes, that restriction can seriously limit your driving opportunities.

California’s roads demand drivers who can safely operate air brakes through mountain passes and the stop-and-go traffic of urban areas like Los Angeles and San Francisco. The California DMV Air Brakes Test covers three main areas: parts of the air brake system (identification and understanding), inspecting air brakes (knowledge of pre-trip inspections, including leaks and pressure loss), and using air brakes properly (braking techniques for different grades and conditions). Drivers must also know how to correctly inspect, test, and operate air brake systems to prevent brake fade or failure on long downhill grades.

You must pass the official written multiple-choice knowledge test with at least 80% correct answers. Failing the test results in a mandatory waiting period and may require an additional retest fee. The good news is that our Air Brakes Practice Tests mirror the official Knowledge Test and provide instant feedback on each response to help you learn faster and retain more. Check out another one of our practice tests after mastering this one: https://driving-tests.org/california/ca-cdl-air-brake-practice-test/.

Industries across the Golden State rely on drivers qualified to handle air brake systems, including agriculture (California Fresh and Produce Express), technology and manufacturing (major freight routes linking Silicon Valley and Los Angeles’s ports), construction and engineering (Bechtel and Turner Construction), and tourism and public transit (Coach USA, Greyhound, and local school districts). Without the air brake qualification, you’re essentially locked out of most high-demand driving jobs in California.

We also encourage you to consider obtaining a Class A CDL. One requirement for this is passing the Combination Vehicles Knowledge Test. We have practice tests for that, too: https://driving-tests.org/california/ca-cdl-combination-test/. You should also give thought to adding valuable endorsements to your CDL. Check one out here: https://driving-tests.org/california/ca-cdl-hazmat-practice-test/.