Utah CDL Air Brake Test (UT) 2026

4.9 out of 5 (65 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Navigating the world of commercial driving requires mastering a range of skills, and understanding air brake systems is crucial for any aspiring CDL holder. Our Utah CDL air brake practice test offers an extensive selection of 20 multiple-choice questions that delve into every aspect of air brake systems. This Utah permit practice test is designed to provide a thorough understanding of key components like compressors, reservoirs, and brake chambers, as well as the operational principles and safety protocols that underpin their use. This Utah learners permit practice test isn't just about rote learning; it's about truly grasping the intricacies of air brakes. With questions that cover the unique brake lag time found in air brakes, drivers will gain a deeper insight into how to calculate stopping distances accurately. To ensure you are well-prepared for your CDL air brake endorsement, you'll need to answer at least 16 questions correctly. This threshold guarantees that you have a solid foundation in the fundamentals of safe and effective air brake operation. Taking the Utah air brakes CDL test multiple times can be incredibly beneficial. Each attempt helps you pinpoint any gaps in your knowledge, allowing you to focus on those areas and improve your overall score. The variety of questions in our Utah CDL air brakes practice test ensures that you are thoroughly prepared for the DMV written test, giving you a comprehensive learning experience. After completing the Utah DMV practice test, you have the opportunity to review your answers. This review process includes hints and explanations for the questions you missed, helping you understand your mistakes and learn from them. This feature is crucial for reinforcing your knowledge and boosting your confidence before you take the actual DMV air brake test. By consistently engaging with the Utah CDL air brakes practice test, you'll be better equipped to handle the real-world demands of commercial driving. Master the skills needed to ensure safety on the road and achieve your CDL endorsement with confidence.
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Sample Utah Air Brakes Test Questions

Question 1

Which instrument must an air-braked CMV have?

  1. A A gauge showing that the vehicle has at least two air tanks
  2. B A pressure gauge showing the air pressure available for braking
  3. C An application-pressure gauge on every vehicle
  4. D A separate tank used only to release the spring brakes

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

Federal equipment rules require an air-braked CMV to have a pressure gauge visible from the normal driving position. It shows the air pressure available for braking. In a dual system, pressure is displayed by separate gauges or by one gauge with two needles; an application-pressure gauge is not installed on every vehicle.

Source: Utah Commercial Driver License Handbook, 2025 Edition — § 5.1.9, “Supply Pressure Gauges”, 49 CFR § 393.51(c)(1) – Warning signals, air pressure and vacuum gauges.

Question 2

In an air-brake system, what is a “wig wag”?

  1. A A mechanical arm that moves into view to warn of low air pressure
  2. B A valve used to drain an air tank automatically
  3. C A component of the brake-light circuit
  4. D A device that adjusts the slack adjusters

Correct answer: A – A mechanical arm that moves into view to warn of low air pressure

A wig wag is a mechanical low-air-pressure warning device. Its arm drops into the driver’s view when system pressure becomes too low. An automatic version rises out of view after pressure is restored, while a manual-reset version must be repositioned by hand.

Source: Utah Commercial Driver License Handbook, 2025 Edition — § 5.1.11, “Low Air Pressure Warning”

Question 3

During the Utah CDL handbook’s air-brake check, the low-air warning should activate before pressure drops below:

  1. A 80 psi
  2. B 55 psi
  3. C 45 psi
  4. D 20 psi

Correct answer: B – 55 psi

The Utah handbook’s inspection procedure requires the warning device to activate before pressure drops below 55 psi in the tank with the lowest pressure. Federal equipment rules also require air-braked CMVs to have a pressure gauge and warning signal, with specifications based partly on the vehicle’s manufacture date. Spring brakes apply at a lower pressure.

Source: Utah Commercial Driver License Handbook, 2025 Edition — § 5.3.3, “Test Low Pressure Warning Signal”, 49 CFR § 393.51(c) – Warning signals, air pressure and vacuum gauges.

Question 4

Why do air brakes take longer to respond than hydraulic brakes?

  1. A Air brakes use a different type of brake drum
  2. B Compressed air must travel through the lines to operate the brakes
  3. C Air brakes have heavier return springs
  4. D The service brakes must overcome the spring brakes

Correct answer: B – Compressed air must travel through the lines to operate the brakes

After the brake pedal is pressed, compressed air needs time to travel through the lines and operate the brakes. This delay, called brake lag, can last one-half second or more. Brake-lag distance must be added to perception, reaction, and braking distances when calculating the total stopping distance of an air-braked vehicle.

Source: Utah Commercial Driver License Handbook, 2025 Edition — § 5.4.4, “Stopping Distance”

Question 5

What does the air-compressor governor control?

  1. A When the compressor starts and stops pumping air into the storage tanks
  2. B How much pressure the brake pedal applies to the brakes
  3. C Whether the compressor needs mechanical repairs
  4. D The engine speed at which the compressor rotates

Correct answer: A – When the compressor starts and stops pumping air into the storage tanks

The governor controls when the compressor pumps air into the storage tanks. It normally allows pumping to begin near the cut-in pressure and stops it at the cut-out pressure. The handbook gives approximate values of 100 psi and 125 psi, but the vehicle manufacturer’s specifications should be checked.

Source: Utah Commercial Driver License Handbook, 2025 Edition — § 5.1.2, “Air Compressor Governor”

Question 6

What is the purpose of an alcohol evaporator in an air-brake system?

  1. A To reduce the risk of ice forming in valves and other air-system parts
  2. B To increase storage-tank pressure
  3. C To replace the need for air-tank drains
  4. D To remove alcohol that has collected in the tanks

Correct answer: A – To reduce the risk of ice forming in valves and other air-system parts

An alcohol evaporator introduces alcohol into the air system to help reduce the risk of icing during cold weather. Ice in air-brake valves or other components can interfere with brake operation. The device does not function as a pressure booster or replace the air tanks’ drainage system.

Source: Utah Commercial Driver License Handbook, 2025 Edition — § 5.1.5, “Alcohol Evaporator”

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