Free Nevada DMV CDL — Air Brakes Practice Test 2026
The Nevada CDL — Air Brakes knowledge test has ~25 questions, and you need ~20 correct (80%) to pass. Practice free with questions written from the official Nevada driver handbook — every one has a clear explanation, and you can retake as often as you like with no sign-up.
Content reviewed against official driver handbooks · August 12, 2026
What's on the Nevada written test
The Nevada CDL — Air Brakes knowledge test has ~25 questions; you need ~20 correct (80%) to pass.
Based on the official Nevada exam format — always confirm current details with your state DMV.
Practice by topic
Focus on one area at a time — each topic has its own set of Nevada practice questions.
How to pass the first time
- Read the official Nevada driver handbook at least once before test day.
- Practice by topic to find your weak spots, then fix them.
- Take full-length practice tests until you pass comfortably every time.
- Read every explanation — understanding beats memorizing.
Nevada CDL — Air Brakes test — frequently asked questions
How many questions are on the Nevada CDL — Air Brakes test?
The Nevada CDL — Air Brakes knowledge test has ~25 questions, and you need ~20 correct (80%) to pass. Our practice tests mirror that format.
How many questions can I miss on the Nevada CDL — Air Brakes test?
You can miss up to ~5 of the ~25 questions and still pass — you need ~20 correct, which is 80%.
Can I retake the practice test?
Yes — practice as often as you like, completely free. The questions and answer choices are shuffled each time.
Can I take the Nevada practice test in Spanish?
Yes. Every question here is available in English and Spanish — switch languages anytime. Many states also offer the real knowledge test in languages other than English; confirm what Nevada offers with your DMV.
Can I practice on my phone?
Yes. The practice tests work in any mobile or desktop browser — no app or sign-up needed — so you can study anywhere.
Are these the real DMV test questions?
No. Our questions are original, written from the current official Nevada driver handbook to match the real test's topics and style. We are not affiliated with any DMV or government agency.
What's the best way to study?
Read the Nevada driver handbook, practice by topic to target weak areas, and finish with full-length tests until you consistently pass.
Other Nevada practice tests
Take the CDL — Air Brakes test in another state
Every Nevada question is written from the official Nevada driver handbook and checked against its current edition. DMV Test Free is a free, independent study resource — not affiliated with any DMV or government agency. About DMV Test Free
Nevada CDL — Air Brakes questions with answers
20 sample questions from the Nevada CDL — Air Brakes question bank — each with the correct answer, a short explanation, and the section of the official handbook it comes from.
Show all 20 questions with answers
1. Which of these describes the stab braking method for an emergency stop?
Correct answer: Brake fully, let off when the wheels lock, and brake fully again once they start rolling
Stab braking means applying the brakes all the way, letting off when the wheels lock, and reapplying fully as soon as the wheels roll again. Braking hard while stopping short of lockup, with tiny steering inputs, is the controlled braking method instead.
Source: Nevada Commercial Driver's License Manual — Section 5.4.3, Emergency Stops
2. When the ABS computer senses that a wheel is about to lock during hard braking, what does it do?
Correct answer: Cuts braking pressure back to a safe level so you keep control
ABS is a computerized system. When it detects that lockup is coming, it eases braking pressure down to a safe level, which lets you keep control of the vehicle. It does not add braking power beyond what your normal brakes provide.
Source: Nevada Commercial Driver's License Manual — Section 5.4.2, Braking with Antilock Brakes
3. On dry pavement at 55 mph, about how much distance does air brake lag alone add to a stop?
Correct answer: About 32 feet
On dry pavement at 55 mph, brake lag adds roughly 32 feet. It is one of four pieces of total stopping distance for an air-braked vehicle, along with perception, reaction and braking distance, which together come to more than 450 feet at that speed.
Source: Nevada Commercial Driver's License Manual — Section 5.4.4, Stopping Distance
4. Which rule does the manual give for leaving an air-braked vehicle unattended?
Correct answer: Set the parking brakes or chock the wheels every time
The manual says never to leave the vehicle unattended unless the parking brakes are set or the wheels are chocked. Otherwise it could roll away and hurt someone or damage property.
Source: Nevada Commercial Driver's License Manual — Section 5.4.8, Parking Brakes
5. Your tractor has ABS, but the trailer you are pulling does not. Compared with having no ABS anywhere, what does the tractor's ABS help with during hard braking?
Correct answer: It helps you hold steering control and makes a jackknife less likely
With ABS on the tractor alone, you should be able to keep steering control and you are less likely to jackknife. You still need to watch the trailer and ease off the brakes, if it is safe, should it begin to swing out.
Source: Nevada Commercial Driver's License Manual — Section 5.4.2, Braking with Antilock Brakes
6. A tractor in your fleet was built in 1995, before air-braked truck tractors were required to have ABS. What does the manual say about vehicles like this?
Correct answer: It may still have ABS, because many older vehicles were fitted with it voluntarily
ABS became mandatory for air-braked truck tractors built on or after March 1, 1997, but many commercial vehicles built before the deadlines were given ABS voluntarily. An older vehicle may still have it.
Source: Nevada Commercial Driver's License Manual — Section 5.1.16, Antilock Braking Systems (ABS)
7. You are on a long downgrade in the proper low gear, and your 'safe' speed is 45 mph. Using the manual's braking technique, at about what speed do you let off the brakes after each application?
Correct answer: About 40 mph
Apply the brakes firmly enough that you clearly feel the vehicle slow until you are about 5 mph under your safe speed (here, about 40 mph), then release. When the speed climbs back to 45 mph, brake again.
Source: Nevada Commercial Driver's License Manual — Section 5.4.6, Proper Braking Technique
8. What is the final step in the Nevada manual's suggested sequence for checking your air brakes?
Correct answer: Check that the parking brake works before moving the vehicle
After the leakage, warning, and pop-out checks, Nevada's suggested sequence closes by confirming that the parking brake actually works before the vehicle is moved.
Source: Nevada Commercial Driver's License Manual — Nevada Information, Air Brakes and Hydraulic Brake Check
9. The low air warning comes on, and you are tempted to keep driving until the spring brakes stop you. Which of these is NOT a reason the manual gives for stopping right away instead?
Correct answer: Spring brakes let go by themselves after a few seconds, so the vehicle will start rolling again
Spring brakes are pushed on by spring force and are held off only by air pressure, so with the air gone they will not let go on their own. The real reasons to stop early are that a heavy load needs a long distance to stop on spring brakes, a light load or slick road can skid, and you keep pedal control only while air remains.
Source: Nevada Commercial Driver's License Manual — Section 5.4.7, Low Air Pressure
10. Which kind of air tank drain requires you to empty the tank yourself after every driving day?
Correct answer: A manually operated drain
With a manual drain, which you open with a quarter turn or a pull on a cable, you have to do the draining yourself at the end of each driving day. Automatic drains push out water and oil on their own, though some can also be drained by hand.
Source: Nevada Commercial Driver's License Manual — Section 5.1.4, Air Tank Drains
11. Brakes are built to absorb a lot of heat. On a long downgrade, what does the manual say pushes them into fading or failing?
Correct answer: Using them too much instead of relying on engine braking
Brakes fade or fail from excessive heat, and that heat comes from overusing the service brakes rather than letting engine braking do its part. Overheating changes the lining so it grips less and makes the drums expand, so the shoes press with less force.
Source: Nevada Commercial Driver's License Manual — Section 5.4.5, Brake Fading or Failure
12. On a newer air-braked truck, what does the parking brake control look like, and how do you set the brakes with it?
Correct answer: A yellow, diamond-shaped knob; pull it out to set the brakes
Newer air-braked vehicles use a yellow, diamond-shaped push-pull knob labeled 'parking brakes.' Pulling it out applies the parking (spring) brakes and pushing it in releases them. Older vehicles may use a lever or a knob of another shape, such as a round blue one.
Source: Nevada Commercial Driver's License Manual — Section 5.1.15, Parking Brake Controls
13. In a typical dual air brake truck, you notice the secondary system's pressure sinking while the primary holds steady. Which brakes are probably not working fully, and what should you expect?
Correct answer: The front-axle brakes; it will take you longer to stop
In the usual setup the secondary system works the front-axle brakes (and possibly one rear axle). When one system runs very low, the brakes it feeds don't work fully and stopping takes longer, so pull over safely and have the air system repaired.
Source: Nevada Commercial Driver's License Manual — Section 5.2, Dual Air Brake
14. Which sequence matches the manual's service brake test for an air-braked vehicle?
Correct answer: Let pressure build to normal, release the parking brake, creep ahead at about 5 mph, and brake firmly with the pedal
Let pressure build to normal, release the parking brake, roll forward slowly at around 5 mph, and brake firmly with the pedal. Then note any pull to one side, strange feel, or slow stop.
Source: Nevada Commercial Driver's License Manual — Section 5.3.3, Step 7 Final Air Brake Check
15. You're in the proper low gear at the top of a long, steep downgrade. How does the manual describe the role of your service brakes on the way down?
Correct answer: They back up the engine's braking, which does the main work
On a long or steep downgrade, the brakes are only an addition to the engine's braking effect. Once in the right low gear, brake firmly enough that you feel the truck clearly slow, let off at about 5 mph below your safe speed, and repeat when you are back up to it.
Source: Nevada Commercial Driver's License Manual — Section 5.4.6, Proper Braking Technique
16. Why does the manual warn against pushing the brake pedal down while the spring brakes are applied?
Correct answer: Spring force and air pressure acting together could damage the brakes
With the spring brakes on, pressing the pedal can stack air pressure on top of the spring force, and that combined load can damage the brakes. Many systems are built to prevent this, but not all are, and even a protected system may not always do its job, so make a habit of keeping your foot off the pedal while the spring brakes are on.
Source: Nevada Commercial Driver's License Manual — Section 5.1.15, Parking Brake Controls
17. You have to brake hard on a slippery road in a truck with working ABS. Which result can you reasonably expect ABS to help with?
Correct answer: Avoiding a skid caused by braking too hard
ABS keeps the wheels from locking, so you can usually steer around a hazard as you brake and avoid skids brought on by over-braking. It may or may not shorten your stop, and it does not add to or take away from your normal braking power.
Source: Nevada Commercial Driver's License Manual — Section 5.4.2, Braking with Antilock Brakes
18. Of the gauges that report on an air brake system, which one is found on every vehicle with air brakes?
Correct answer: A supply pressure gauge linked to the air tank
Every air-braked vehicle has a supply pressure gauge hooked to the air tank, showing how much pressure the tanks hold; a dual system shows both halves with two gauges or one gauge with two needles. The application pressure gauge, which shows how hard you are applying the brakes, is not on all vehicles.
Source: Nevada Commercial Driver's License Manual — Section 5.1.9, Supply Pressure Gauges
19. Air needs time to flow through the lines before air brakes apply. About how long does that delay usually take?
Correct answer: Half a second or more
Hydraulic brakes on cars and light or medium trucks work instantly, but air brakes have brake lag: it takes one half second or longer for air to reach the brakes after you push the pedal. That delay adds distance to every stop.
Source: Nevada Commercial Driver's License Manual — Section 5.4.4, Stopping Distance
20. Conditions tonight mean you shouldn't set the parking brakes on your air-braked truck, but you still need to keep it from moving. What does the manual tell you to use?
Correct answer: Wheel chocks, with the vehicle on a level surface
When the brakes are very hot, or very wet in freezing weather, the manual says not to set the parking brakes. Hold the vehicle with wheel chocks on level ground instead.
Source: Nevada Commercial Driver's License Manual — Section 5.4.8, Parking Brakes