Nebraska CDL Air Brake Test (NE) 2026

5 out of 5 (45 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Welcome to the Nebraska CDL air brakes practice test, your gateway to mastering the essential skills for safe and effective air brake operation. This test is meticulously designed to provide you with an in-depth understanding of air brake systems, covering crucial components such as compressors, reservoirs, and brake chambers. With 20 multiple-choice questions, this Nebraska permit practice test simulates real-world driving scenarios, enhancing your readiness for the actual Nebraska DMV air brake test. In Nebraska, where driving laws and regulations are specific to the state, our learners permit practice test ensures you are familiar with local rules, safety protocols, and road signs. This focus on state-specific information means that you won't just be preparing for the CDL air brake test, but you'll also become a more knowledgeable and confident driver on Nebraska's roads. Each question is crafted to mirror those on the real Nebraska DMV air brake test, both in format and content, providing a realistic test-taking experience that will help you feel at ease on test day. Understanding the unique characteristics of air brakes, such as the brake lag time, is vital for calculating stopping distances accurately. This Nebraska practice driving test emphasizes these critical elements, allowing you to build a strong foundation of knowledge. To pass, you'll need to answer at least 16 out of 20 questions correctly, ensuring you're well-prepared to secure your commercial driver's license air brakes endorsement. By engaging with this Nebraska CDL air brakes practice test, you are not only preparing for the test itself but also equipping yourself with the practical skills and knowledge needed for a successful driving career. Whether you're a seasoned driver looking to refresh your skills or a new driver starting your journey, this Nebraska permit practice test is an invaluable resource on your path to becoming a safer, more competent driver. Dive in, challenge yourself, and get ready to excel.
FREE CDL Practice Test App
Pass your Nebraska CDL Air Brake test with the NextDoorDriving app. Real questions and answers—100% free and ad-free.
Download on the App Store

Sample Nebraska Air Brakes Test Questions

Question 1

Which part of an air-brake system applies and releases the brakes when the driver operates the brake pedal?

  1. A Parking brake system
  2. B Service brake system
  3. C Emergency brake system
  4. D None of these

Correct answer: B – Service brake system

The service brake system applies and releases the brakes through the brake pedal during normal driving. The parking brake system is operated by the parking-brake control. The emergency system uses components of the service and parking systems if a brake-system failure occurs.

Source: Nebraska Commercial Driver’s License Manual — § 5, “Air Brakes”

Question 2

Repeated heavy use of the service brakes to control speed can overheat air brakes.

  1. A True
  2. B False

Correct answer: A – True

Braking creates heat, and excessive service-brake use can produce more heat than the system can safely handle. Overheated brakes may fade, requiring progressively greater pedal pressure for the same stopping force. Continued misuse can eventually cause the brakes to lose their ability to slow or stop the vehicle.

Source: Nebraska Commercial Driver’s License Manual — § 5.4.5, “Brake Fading or Failure”

Question 3

If an air-brake vehicle has no automatic tank drains, when should its air tanks be drained?

  1. A At the end of every working day
  2. B After every four hours of operation
  3. C Once each week
  4. D Every other week

Correct answer: A – At the end of every working day

The Nebraska CDL manual directs drivers to drain manually operated air tanks at the end of each day of driving. Water and compressor oil collect in the bottom of the tanks and can damage the system. In cold weather, accumulated water may freeze and interfere with brake operation.

Source: Nebraska Commercial Driver’s License Manual — § 5.1.4, “Air Tank Drains”

Question 4

Which instrument must an air-brake-equipped commercial vehicle have?

  1. A An application-pressure gauge on every brake chamber
  2. B A pressure gauge showing the air available for braking
  3. C A backup hydraulic-brake pressure gauge
  4. D A gauge for each of at least three air tanks

Correct answer: B – A pressure gauge showing the air available for braking

Federal equipment rules require an air-braked commercial vehicle to have a pressure gauge that indicates the air available for braking. A dual system may use separate gauges or one gauge with two needles. An application-pressure gauge shows pressure being applied to the brakes, but that gauge is not installed on every vehicle.

Source: Nebraska Commercial Driver’s License Manual — § 5.1.9, “Supply Pressure Gauges”, 49 CFR § 393.51(c) – Warning signals, air pressure and vacuum gauges

Question 5

For a single air-brake vehicle with the engine off and brakes released, the air-pressure loss rate should be less than:

  1. A 1 psi per minute
  2. B 2 psi per minute
  3. C 3 psi per minute
  4. D 4 psi per minute

Correct answer: B – 2 psi per minute

The Nebraska CDL manual states that a single vehicle should lose less than 2 psi in one minute during the released-brake leakage test. A combination vehicle should lose less than 3 psi per minute. Do not confuse this with the applied-brake test, which uses limits of 3 psi for a single vehicle and 4 psi for a combination vehicle.

Source: Nebraska Commercial Driver’s License Manual — § 5.3, “Inspecting Air Brake Systems”

Question 6

An alcohol evaporator is used to condense the air inside an air-brake system.

  1. A True
  2. B False

Correct answer: B – False

An alcohol evaporator introduces alcohol into the air-brake system. The alcohol helps reduce the risk of ice forming in brake valves and other components during cold weather. It does not condense compressed air, and air tanks still require regular drainage unless automatic drains are installed.

Source: Nebraska Commercial Driver’s License Manual — § 5.1.5, “Alcohol Evaporator”

More Nebraska CDL Practice Tests
Other CDL Endorsements