Massachusetts CDL Air Brakes Practice Test

The Massachusetts CDL Air Brakes test is a multiple-choice knowledge test you take for your commercial learner's permit. Massachusetts Registry of Motor Vehicles (RMV) says you need 80% to pass (source).

Last updated Oct 7, 2026. FirstTry CDL is a CDL permit test prep site by Hive Asset Group, LLC.

By Scott Wilder, Editor

Last reviewed against the Massachusetts CDL manual on October 7, 2026

Scott Wilder on X | scottwilderhq.com

FirstTry CDL is a CDL permit test prep site by Hive Asset Group, LLC. It offers free exam-style practice tests built from the official CDL manual. FirstTry CDL is not affiliated with any DMV, FMCSA or government agency. Practice questions are exam-style questions built from the official CDL manual, not actual test questions.

Massachusetts CDL permit facts

What	What Massachusetts says	Source
Air Brakes pass mark	80%	Official page
Air Brakes test questions	25	Official page
CLP fee	$30 permit application fee	Official page
CLP validity	180 days from the date of issue	Official page
Test languages	CLP general knowledge and all endorsement exams are offered in English, Spanish and Portuguese. The road test must be given in English, and per federal regulation a foreign language interpreter is not permitted. The skills test sheet says a person is not eligible to operate a CMV unless they can read and speak English well enough to talk with the public, understand highway signs, answer official questions and make entries on reports (49 CFR 391.11).	Official page

20 question Air Brakes practice test

1. What does the emergency brake system use to stop the vehicle when a brake system fails?
1. A. A separate set of brakes used only in emergencies
2. B. Parts of the service and parking brake systems
3. C. Only the parking brake system
4. D. Only the trailer brakes
Show answer
Answer: B. Parts of the service and parking brake systems
The emergency system shares parts of the service and parking brake systems.
From the official CDL manual, section 5.
2. During the spring brake check, the parking brake knob pops out at 30 psi. What does this show?
1. A. A defect, because it should pop out at 85 psi
2. B. Normal, because it is within the 20 to 45 psi range
3. C. A defect, because it should stay in until 10 psi
4. D. A defect, because it should pop out at 55 psi
Show answer
Answer: B. Normal, because it is within the 20 to 45 psi range
Popping out at 30 psi is within the 20 to 45 psi range, so the spring brakes are coming on as they should.
From the official CDL manual, section 5.4.7.
3. How can you find out if your air brake vehicle should have ABS?
1. A. Read the manufacture date on the label
2. B. Look for a red lamp on the dash panel
3. C. Count the air tanks and the brake chambers
4. D. Read the application pressure gauge
Show answer
Answer: A. Read the manufacture date on the label
The certification label shows the date of manufacture, which tells you if ABS is required.
From the official CDL manual, section 5.1.16.
4. Air brake truck tractors built on or after what date must have ABS?
1. A. March 1, 1975
2. B. March 1, 1997
3. C. March 1, 1998
4. D. March 1, 2005
Show answer
Answer: B. March 1, 1997
Truck tractors with air brakes built on or after March 1, 1997 must have ABS.
From the official CDL manual, section 5.1.16.
5. Your bus has dual parking control valves. You push the spring loaded button in to move, then let go. What happens?
1. A. The spring brakes stay released
2. B. The air tank refills
3. C. The compressor turns off
4. D. The spring brakes come on again
Show answer
Answer: D. The spring brakes come on again
When you release the button, the spring brakes come on again.
From the official CDL manual, section 5.1.15.
6. Which kind of brakes work instantly, with no brake lag?
1. A. Drum brakes with air
2. B. Spring brakes
3. C. Hydraulic brakes
4. D. Air brakes
Show answer
Answer: C. Hydraulic brakes
The manual says hydraulic brakes work instantly.
From the official CDL manual, section 5.4.4.
7. You are using the controlled braking method. How should you move the steering wheel?
1. A. Make large, quick turns
2. B. Hold the wheel tightly and never move it
3. C. Turn it back and forth
4. D. Keep the movements very small
Show answer
Answer: D. Keep the movements very small
Keep steering wheel movements very small during controlled braking.
From the official CDL manual, section 5.4.3.
8. Only the tractor of your combination has ABS. What is the benefit during braking?
1. A. The trailer can never swing out
2. B. Less chance of jackknifing and you can keep steering control
3. C. You can stop in half the distance
4. D. You do not need to watch the trailer
Show answer
Answer: B. Less chance of jackknifing and you can keep steering control
With ABS on the tractor, you should keep steering control and jackknife less.
From the official CDL manual, section 5.4.2.
9. Tractor and straight truck spring brakes come fully on when air pressure drops to what range?
1. A. 5 to 15 psi
2. B. 55 to 80 psi
3. C. 20 to 45 psi
4. D. 100 to 125 psi
Show answer
Answer: C. 20 to 45 psi
The manual gives a range of 20 to 45 psi, typically 20 to 30 psi.
From the official CDL manual, section 5.1.14.
10. What does a wig wag do when system air pressure gets too low?
1. A. Applies the spring brakes right away
2. B. Sounds a loud horn outside the cab
3. C. Opens the safety valve to let air out
4. D. Drops a mechanical arm into your view
Show answer
Answer: D. Drops a mechanical arm into your view
A wig wag is a mechanical arm that drops into view at low pressure.
From the official CDL manual, section 5.1.11.
11. A truck was built in 1996. What kind of slack adjusters does it have?
1. A. Manual slack adjusters only
2. B. No slack adjusters
3. C. Automatic slack adjusters
4. D. Slack adjusters on the front axle only
Show answer
Answer: C. Automatic slack adjusters
The manual says all vehicles built since 1994 have automatic slack adjusters.
From the official CDL manual, section 5.3.2.
12. Which air brake system applies and releases the brakes when you use the brake pedal in normal driving?
1. A. The service brake system
2. B. The parking brake system
3. C. The emergency brake system
4. D. The foundation brake system
Show answer
Answer: A. The service brake system
The service brakes work when you press and release the brake pedal.
From the official CDL manual, section 5.
13. A dual air brake vehicle has a bad low pressure warning. What does the manual say can happen?
1. A. Nothing, because a dual system never loses air
2. B. The spring brakes will release and the vehicle may roll
3. C. The brakes will work better because of the second circuit
4. D. Stopping distance goes up, with limited braking before the spring brakes come on
Show answer
Answer: D. Stopping distance goes up, with limited braking before the spring brakes come on
In a dual system, a failed warning means longer stopping distance and only limited braking before the spring brakes apply.
From the official CDL manual, section 5.3.3.
14. A truck has ABS on only one axle. What does the manual say about that?
1. A. It is not allowed
2. B. It still gives you more control while braking
3. C. It gives no benefit
4. D. It makes the brakes grab
Show answer
Answer: B. It still gives you more control while braking
The manual says even one ABS axle gives more control during braking.
From the official CDL manual, section 5.4.2.
15. Why must emergency and parking brakes be held on by mechanical force?
1. A. Air is too expensive
2. B. Springs are lighter than air lines
3. C. Air pressure can eventually leak away
4. D. Drivers forget to use air
Show answer
Answer: C. Air pressure can eventually leak away
Air pressure can eventually leak away, so these brakes must be held on mechanically.
From the official CDL manual, section 5.1.14.
16. Which vehicles may have a front brake limiting valve control in the cab?
1. A. Some older vehicles made before 1975
2. B. All vehicles made after 1997
3. C. Only buses that carry passengers
4. D. Only trailers pulled by tractors
Show answer
Answer: A. Some older vehicles made before 1975
Some vehicles made before 1975 have the cab control marked normal and slippery.
From the official CDL manual, section 5.1.13.
17. What can ABS help you do in a hard stop?
1. A. Steer around an obstacle while braking
2. B. Always stop in a shorter distance
3. C. Follow closer to the vehicle ahead
4. D. Skip the use of engine braking on grades
Show answer
Answer: A. Steer around an obstacle while braking
With ABS you may or may not stop faster, but you should be able to steer around an obstacle while braking.
From the official CDL manual, section 5.4.2.
18. Your brakes are wet. How can you dry them before parking?
1. A. Press them hard at high speed
2. B. Use them lightly while driving in a low gear
3. C. Drain the tanks
4. D. Set the parking brake right away
Show answer
Answer: B. Use them lightly while driving in a low gear
The manual says to use the brakes lightly in a low gear to heat and dry them.
From the official CDL manual, section 5.4.8.
19. Your vehicle has no ABS and you brake hard on a slippery road. What happens if the steering wheels lock up?
1. A. The spring brakes release
2. B. You lose steering control
3. C. The air tanks refill faster
4. D. The vehicle stops in a shorter distance
Show answer
Answer: B. You lose steering control
When steering wheels lock up, you lose steering control.
From the official CDL manual, section 5.4.2.
20. What is the controlled braking method?
1. A. Pressing the pedal all the way, then releasing when the wheels lock
2. B. Tapping the pedal lightly many times in a row
3. C. Braking as hard as you can without locking the wheels
4. D. Using only the engine brake and the parking brake
Show answer
Answer: C. Braking as hard as you can without locking the wheels
In controlled braking you apply the brakes as hard as you can without locking the wheels.
From the official CDL manual, section 5.4.3.

Massachusetts CDL Air Brakes questions

What score do you need to pass the Massachusetts CDL Air Brakes test?

Massachusetts says you need 80% to pass the Air Brakes test.

Is the Massachusetts CDL Air Brakes test the same as other states?

The Air Brakes test is built on the same federal knowledge standards in every state, so the topics match the CDL manual. Massachusetts uses its own handbook: https://www.mass.gov/doc/cdl-manual-march-2025-version/download

How much does a CDL permit cost in Massachusetts?

CLP fee: $30 permit application fee.

What languages is the Massachusetts CDL knowledge test offered in?

CLP general knowledge and all endorsement exams are offered in English, Spanish and Portuguese. The road test must be given in English, and per federal regulation a foreign language interpreter is not permitted. The skills test sheet says a person is not eligible to operate a CMV unless they can read and speak English well enough to talk with the public, understand highway signs, answer official questions and make entries on reports (49 CFR 391.11).

Sources

https://www.mass.gov/how-to/apply-for-a-commercial-learners-permit-clp
https://www.mass.gov/doc/rmv-schedule-of-fees/download
https://www.mass.gov/news/massachusetts-registry-of-motor-vehicles-now-offering-commercial-learners-permit-exams-in-spanish-and-portuguese
https://www.mass.gov/doc/cdl-manual-march-2025-version/download
Manual sections used in this test: 5; 5.1.11; 5.1.13; 5.1.14; 5.1.15; 5.1.16; 5.3.2; 5.3.3; 5.4.2; 5.4.3; 5.4.4; 5.4.7; 5.4.8

Air Brakes practice test in nearby states