Vermont CDL Air Brakes Practice Test (VT) 2

5 out of 5 (41 votes)
80% Passing score
20 Questions
4 Mistakes allowed
Preparing for your CDL air brake endorsement in Vermont requires thorough practice and familiarity with the specifics of our roads and driving conditions. Our VT CDL air brakes practice test is meticulously designed to simulate the real DMV test environment. With 20 multiple-choice questions that delve into essential topics like air brake components, operation, safety inspections, and stopping distance calculations, this test is your comprehensive resource. To pass, you need to answer at least 16 questions correctly, ensuring you're well-prepared for the official test. Living in Vermont means driving through diverse weather conditions and scenic, yet challenging, terrains. From navigating the snowy roads in winter to the lush, winding routes through our beautiful Green Mountains in summer, a solid understanding of air brakes is crucial for safe driving. This Vermont CDL air brakes practice test not only prepares you for the DMV test but also equips you with knowledge to handle real-life driving scenarios specific to our state. Our permit practice test is crafted to mirror the actual DMV test closely, both in content and phrasing, providing you with an authentic practice experience. Although the DMV does not publish real test questions, our VT DMV air brake test covers identical topics, helping you grasp the essential concepts. By including real-life scenarios, this learner's permit practice test ensures you are not just ready for the written test but also prepared for safe driving on Vermont's roads. Supplementing your preparation with additional study materials such as the Vermont driver's handbook, state-certified driver's ed courses, flashcards, and road sign charts can enhance your readiness. These resources target all areas of the DMV permit test, ensuring a comprehensive understanding of the material. Take advantage of our VT CDL air brakes practice test to build confidence and competence. With this practice tool, you'll be well-equipped to tackle the CDL air brake test and drive safely and efficiently on Vermont's roads.
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Sample Vermont Air Brakes Test Questions

Question 1

A vehicle has manual air-tank drains instead of automatic drains. When should the tanks be drained?

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

Correct answer: A – At the end of each day of driving

The Vermont CDL manual instructs drivers to drain manually operated air tanks at the end of each day of driving. Water and compressor oil collect at the bottom of the tanks and can harm the air-brake system. In cold weather, accumulated water may freeze and contribute to brake failure.

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

Question 2

On a typical truck, at about what pressure should the air-compressor governor cut in?

  1. A 80 psi
  2. B 100 psi
  3. C 125 psi
  4. D 150 psi

Correct answer: B – 100 psi

The governor normally allows the compressor to begin pumping again when tank pressure falls to about 100 psi. It stops the compressor near the cut-out pressure, usually around 125 psi. The actual cut-in and cut-out settings should be checked against the vehicle manufacturer’s specifications.

Source: Vermont Commercial Driver’s License Manual — § 5.1.2, “Air Compressor Governor”

Question 3

Which description best matches spring brakes?

  1. A Hydraulically operated service brakes
  2. B Air-operated brakes used only during normal stops
  3. C Mechanically applied parking and emergency brakes
  4. D Brakes installed only on trailers

Correct answer: C – Mechanically applied parking and emergency brakes

Spring brakes commonly provide parking and emergency braking through mechanical spring force. During normal driving, air pressure holds the springs back. Releasing that air applies the brakes, and a major loss of air pressure can also cause the spring brakes to engage.

Source: Vermont Commercial Driver’s License Manual — § 5.1.14, “Spring Brakes”

Question 4

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

  1. A Shut off the engine, turn on electrical power, and repeatedly press and release the brake pedal
  2. B Leave the engine running and pull each slack adjuster
  3. C Release the parking brake and accelerate the engine
  4. D Make a hard stop while traveling at least 20 mph

Correct answer: A – Shut off the engine, turn on electrical power, and repeatedly press and release the brake pedal

The Vermont CDL manual’s procedure is to shut off the engine, turn on electrical power, and press and release the brake pedal until the warning activates. Vehicles built under FMVSS No. 121 must warn the driver when reservoir pressure is below 60 psi. Older power units not subject to that standard have a 55-psi or one-half-cutout threshold, whichever is less.

Source: Vermont Commercial Driver’s License Manual — § 5.3.3, “Step 7 Final Air Brake Check”, 49 CFR § 571.121 S5.1.5 – Standard No. 121; Air brake systems, 49 CFR § 393.51(c) – Warning signals, air pressure and vacuum gauges

Question 5

During normal driving, which system applies and releases the brakes when the driver presses the brake pedal?

  1. A Parking brake system
  2. B Service brake system
  3. C Emergency brake system
  4. D Trailer supply system

Correct answer: B – Service brake system

The service brake system operates when the driver uses the brake pedal, also called the foot or treadle valve. The parking brake system is controlled separately. The Vermont CDL manual distinguishes both from the emergency brake system, which uses parts of the service and parking systems during a brake-system failure.

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

Question 6

What is the main purpose of a vehicle retarder?

  1. A To prevent every wheel skid
  2. B To apply additional braking to nondrive axles
  3. C To help slow the vehicle and reduce service-brake wear
  4. D To replace the parking and emergency brakes

Correct answer: C – To help slow the vehicle and reduce service-brake wear

Retarders help slow a commercial vehicle, reducing how often the service brakes must be used and limiting brake wear. When activated, they generally apply retarding force to the drive wheels as the accelerator is released. Because this can cause a skid when traction is poor, the manual advises turning the retarder off on wet, icy, or snow-covered roads.

Source: Vermont Commercial Driver’s License Manual — § 2.3.4, “Retarders”

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