Wyoming CDL Air Brake Test (WY) 2026

5 out of 5 (31 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Driving in Wyoming's rugged terrain requires a solid understanding of how air brake systems work, especially for those pursuing a commercial driver's license. The Wyoming CDL air brake test on this page is designed to thoroughly prepare you for the state's official test, ensuring you're ready to handle the demanding conditions on our roads. This Wyoming CDL air brake practice test features 20 multiple-choice questions, each carefully crafted to reflect the real DMV test. As you work through the Wyoming drivers license practice test, you'll explore critical aspects of air brake systems, including compressors, reservoirs, brake chambers, and the unique brake lag time inherent to these systems. Understanding brake lag time is crucial for calculating stopping distances, particularly when navigating Wyoming's diverse landscapes, from mountain passes to open plains. The WY CDL air brake test doesn't just test your knowledge; it's a learning tool that ensures you're not only prepared to pass but also equipped with the fundamentals necessary for safe driving. After completing the test, you'll receive a detailed summary of your performance, highlighting the questions you answered incorrectly. This feature allows you to review and learn from your mistakes, reinforcing your understanding of the material. The format and content of this CDL air brakes practice test closely mimic the official test, providing an authentic testing experience. Each question is based on the official Wyoming drivers manual, the same source used by the DMV to create the actual test. This ensures that the material you study is directly relevant to the questions you'll encounter on test day. Achieving a passing score on this Wyoming DMV air brake test requires you to correctly answer at least 16 of the 20 questions, demonstrating your readiness to safely and effectively operate vehicles equipped with air brakes. Whether you're preparing for your first attempt at the air brakes endorsement or brushing up on your knowledge, this Wyoming permit practice test is an essential step in your preparation.
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Sample Wyoming Air Brakes Test Questions

Question 1

Under good traction and brake conditions, an air-brake vehicle traveling at 55 mph has a total stopping distance of only about 100 feet.

  1. A. TRUE
  2. B. FALSE

Correct answer: B. – FALSE

At 55 mph, the air-brake lag alone adds approximately 32 feet after the brake pedal is pressed. When perception distance, reaction distance, brake lag, and effective braking distance are combined, an average driver’s total stopping distance under good conditions exceeds 450 feet. A distance of 100 feet is far too short.

Source: 2024 Wyoming Commercial Driver License Manual — § 5.4.4, “Stopping Distance”

Question 2

During cold Wyoming weather, what daily attention does an air-brake alcohol evaporator require?

  1. A. Drain the alcohol from the container
  2. B. Lubricate the system with five-weight oil
  3. C. Replace the alcohol container every day
  4. D. Check the alcohol level and refill as necessary

Correct answer: D. – Check the alcohol level and refill as necessary

An alcohol evaporator introduces alcohol into the air system to reduce the risk of ice in valves and other components. During cold weather, check its container every day and add alcohol as necessary. Air tanks must still be drained to remove water and oil unless the system has automatic drain valves.

Source: 2024 Wyoming Commercial Driver License Manual — § 5.1.5, “Alcohol Evaporator”

Question 3

How should you normally brake a tractor-trailer combination equipped with ABS?

  1. A. Use normal braking procedures and only the pressure needed to stop safely
  2. B. Apply more brake pressure than usual at every stop
  3. C. Fully slam on the brakes whenever slowing
  4. D. Use repeated stab braking

Correct answer: A. – Use normal braking procedures and only the pressure needed to stop safely

Brake normally in a tractor-trailer equipped with ABS. Apply only the braking force needed to stop safely and remain in control, regardless of whether ABS is on the tractor, trailer, or both. Monitor the combination as it slows and reduce brake pressure, when safe, if the trailer begins to swing or the tractor starts to jackknife.

Source: 2024 Wyoming Commercial Driver License Manual — § 6.3.2, “Braking with ABS”

Question 4

Which force may hold a truck, truck tractor, or bus parking brake in the applied position?

  1. A. Spring pressure
  2. B. Air pressure alone
  3. C. Hydraulic-fluid pressure alone
  4. D. Any of these

Correct answer: A. – Spring pressure

Federal equipment rules require a parking brake to remain applied using energy other than air, hydraulic-fluid, or electric pressure. Mechanical spring pressure satisfies this requirement and is commonly used in air-brake systems. Air pressure normally holds spring brakes released while driving; removing that pressure allows the springs to apply the brakes.

Source: 2024 Wyoming Commercial Driver License Manual — § 5.1.14, “Spring Brakes”, 49 CFR § 393.41(b) — Parking Brake System

Question 5

What function does the air-compressor governor control?

  1. A. When the compressor pumps air into the storage tanks
  2. B. How much pressure the brake pedal sends to the brakes
  3. C. Whether the compressor has enough lubricating oil
  4. D. The compressor’s rotational speed

Correct answer: A. – When the compressor pumps air into the storage tanks

The governor controls when the air compressor pumps into the storage tanks. At the cut-out pressure, commonly around 125 psi, the governor stops the compressor from pumping. When tank pressure drops to the cut-in level, commonly around 100 psi, it allows the compressor to begin pumping again. Manufacturer specifications govern the exact pressures.

Source: 2024 Wyoming Commercial Driver License Manual — § 5.1.2, “Air Compressor Governor”

Question 6

Which procedure correctly tests the low-air-pressure warning signal?

  1. A. With the vehicle parked, shut off the engine, turn on electrical power, and repeatedly apply and release the brake pedal
  2. B. Push inward on a slack adjuster while the engine runs
  3. C. Release the parking brake and pull forcefully on a slack adjuster
  4. D. Make a hard stop while traveling at least 20 mph

Correct answer: A. – With the vehicle parked, shut off the engine, turn on electrical power, and repeatedly apply and release the brake pedal

With enough pressure that the warning is initially off, shut down the engine and turn on the electrical power. Repeatedly apply and release the brake pedal to lower tank pressure. The warning signal must activate before pressure falls below 60 psi in the tank—or the lowest-pressure tank in a dual system. Do not perform this test while driving.

Source: 2024 Wyoming Commercial Driver License Manual — § 5.3.3, “Step 7 Final Air Brake Check”

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