Utah CDL — Air Brakes Practice Test
The Utah CDL — Air Brakes knowledge test has 25 questions, and you need 20 correct (80%) to pass. Practice free with questions written from the official Utah 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 · July 7, 2026
What's on the Utah written test
The Utah CDL — Air Brakes knowledge test has 25 questions; you need 20 correct (80%) to pass.
Based on the official Utah 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 Utah practice questions.
Speed limits, turning and signaling rules, headlight and seat-belt requirements, and the everyday laws every driver must follow.
How to read traffic signals, lane lines, and pavement markings — including yellow and white lines, arrows, and flashing lights.
Following distance, scanning, blind spots, using your lights, and the habits that prevent crashes and keep you in control.
Legal and illegal parking, colored curbs, distances from hydrants and crossings, and how to park safely on hills.
Choosing a safe speed, keeping a space cushion, adjusting for weather and traffic, and understanding stopping distance.
What to do when things go wrong — brake failure, tire blowouts, skids, and stalling on railroad tracks.
The point system, license suspension, provisional-license rules, insurance requirements, and other licensing basics.
How to pass the first time
- Read the official Utah 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.
Utah CDL — Air Brakes test — frequently asked questions
How many questions are on the Utah CDL — Air Brakes test?
The Utah 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 Utah 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 Utah 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 Utah 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 Utah 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 Utah driver handbook, practice by topic to target weak areas, and finish with full-length tests until you consistently pass.
Other Utah practice tests
Take the CDL — Air Brakes test in another state
Every Utah question is written from the official Utah 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
Utah CDL — Air Brakes questions with answers
20 sample questions from the Utah CDL — Air Brakes question bank — each with the correct answer, a short explanation, and the section of the official handbook it comes from.
1. How often must you empty air tanks that have only manual drain valves?
Correct answer: When you finish driving for the day
Manually drained tanks need their water and oil released once you finish driving for the day.
Source: 5.1.4 Air Tank Drains
2. What is a key benefit ABS gives you during hard braking?
Correct answer: You can steer around an obstacle while braking
ABS may not stop you any faster, but by preventing lockup it lets you keep steering control to maneuver around a hazard.
Source: 5.4.2 Braking with Antilock Brakes
3. An air brake setup actually combines how many separate braking systems into one?
Correct answer: Three - the service, parking, and emergency brakes
The handbook explains that air brakes are really three systems working together: the service brake, the parking brake, and the emergency brake.
Source: Section 5 - Air Brakes (introduction)
4. What is the 'wig wag' found on some air-brake vehicles?
Correct answer: A mechanical arm that drops into view when pressure is low
The wig wag is a mechanical arm that swings into the driver's view when system pressure falls below 55 psi.
Source: 5.1.11 Low Air Pressure Warning
5. How large a crack in a brake drum makes it unsafe to keep in service?
Correct answer: A crack longer than half the width of the friction area
A drum or disc is unsafe once a crack runs longer than half the width of its friction surface.
Source: 5.3.2 Walk-around Inspection
6. Compared with a car's hydraulic brakes, how quickly do air brakes respond?
Correct answer: A little slower, since the air must travel through the lines
Hydraulic brakes act instantly, while air brakes have a short lag as the air travels out to each brake.
Source: 5.4.4 Stopping Distance
7. Before walking away from a parked commercial vehicle, what must you do?
Correct answer: Set the parking brakes or chock the wheels
An unattended vehicle can roll away, so you must set the parking brakes or chock the wheels.
Source: 5.4.8 Parking Brakes
8. Since which year have all newly built vehicles come with automatic slack adjusters?
Correct answer: 1994
The manual states that every vehicle built since 1994 comes with automatic slack adjusters.
Source: 5.3.2 Walk-around Inspection
9. Why shouldn't you keep driving until the spring brakes engage on their own?
Correct answer: You should stop while you can still control the brakes
When the low-air warning first appears, stop promptly while you still have brake control rather than waiting for the spring brakes to grab.
Source: 5.1.14 Spring Brakes
10. On a long, steep downgrade, the service brakes should be treated as what?
Correct answer: A supplement to the engine's braking effect
The manual stresses that on a steep grade the brakes only add to the slowing effect of the engine held in a low gear.
Source: 5.4.6 Proper Braking Technique
11. On large buses, the low-pressure warning devices commonly activate at about what pressure?
Correct answer: 80 to 85 psi
For big buses, these warning devices commonly trip much earlier, around 80 to 85 psi.
Source: 5.1.11 Low Air Pressure Warning
12. What is the defect most often found during roadside inspections?
Correct answer: Brakes that are out of adjustment
The handbook notes that out-of-adjustment brakes are the defect inspectors turn up most often at roadside checks.
Source: 5.3.2 Walk-around Inspection
13. At 55 mph on dry pavement, roughly how much extra distance does air brake lag add?
Correct answer: About 32 feet
According to the manual, that lag tacks on roughly 32 feet of travel at 55 mph on dry roads.
Source: 5.4.4 Stopping Distance
14. On a newer air-brake vehicle, how do you set the parking brakes?
Correct answer: Pull the yellow, diamond-shaped knob out
Newer vehicles use a diamond-shaped yellow push-pull knob; pulling it out applies the spring/parking brakes and pushing it in releases them.
Source: 5.1.15 / 5.4.8 Parking Brakes
15. Which of these is required equipment on every vehicle with air brakes?
Correct answer: A low-air-pressure warning signal
A low-air-pressure warning signal is mandatory on air-brake vehicles; the other items listed are optional add-ons.
Source: 5.1.11 Low Air Pressure Warning
16. During stab braking, when should you reapply the brakes after releasing them?
Correct answer: As soon as the wheels start rolling again
In stab braking you release when the wheels lock, then reapply fully only once the wheels begin turning again.
Source: 5.4.3 Emergency Stops
17. Using the recommended snub-braking method downhill, about how long should each brake application last?
Correct answer: Roughly three seconds
You apply firmly to slow about 5 mph below your safe speed and then release; each of these applications should last roughly three seconds.
Source: 5.4.6 Proper Braking Technique
18. The visible low-air warning must switch on before tank pressure drops below what level?
Correct answer: 55 psi
A required warning you can see must activate before the air pressure falls under 55 psi.
Source: 5.1.11 Low Air Pressure Warning
19. A manual slack adjuster probably needs adjusting if it moves more than about how much at the push-rod connection?
Correct answer: One inch
If a slack adjuster moves more than roughly one inch at the push-rod connection, it likely needs to be adjusted.
Source: 5.3.2 Walk-around Inspection
20. Total stopping distance with air brakes is made up of how many separate factors?
Correct answer: Four
The four pieces are perception distance, reaction distance, the brake lag distance, and braking distance.
Source: 5.4.4 Stopping Distance