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Free Practice Questions for Utah CDL Air Brakes

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Sample Utah CDL Air Brakes Practice Questions

Try these sample questions to review concepts for the Utah CDL Air Brakes exam. Each question includes a detailed explanation. Start the interactive quiz above for the full 150+ question experience with AI tutoring.

1Which three braking systems make up a commercial vehicle air brake system?
A.Service, parking, and emergency brake systems
B.Primary, secondary, and compressor brake systems
C.Drum, disc, and antilock brake systems
D.Foundation, retarder, and steering brake systems
Explanation: The Utah CDL handbook identifies the service, parking, and emergency brake systems as the three parts of an air brake system. The emergency system uses parts of the service and parking systems to stop the vehicle after an air-system failure.
2How does an air compressor governor normally control compressor operation?
A.It stops pumping near 100 psi and resumes near 55 psi
B.It stops pumping near the manufacturer's cut-out pressure and resumes near the cut-in pressure
C.It vents both reservoirs whenever the service brakes are released
D.It varies brake-chamber pressure according to vehicle speed
Explanation: The governor stops compressor pumping at the manufacturer's cut-out pressure and restarts it at the cut-in pressure. The Utah handbook uses about 125 psi for cut-out and about 100 psi for cut-in while directing drivers to know the vehicle specifications.
3At approximately what pressure is the air-tank safety relief valve normally set to open?
A.55 psi
B.100 psi
C.150 psi
D.120 to 140 psi
Explanation: The safety relief valve is normally set to open at about 150 psi to protect the tank and system from excessive pressure. A valve that releases air indicates a fault that needs mechanical repair.
4Which sequence correctly describes how an S-cam brake applies?
A.The compressor turns the drum, and the governor presses the shoes outward
B.The foot valve moves the slack adjuster mechanically, and the pushrod meters reservoir air
C.Reservoir air enters the drum and forces the lining directly against the wheel
D.Air moves the chamber pushrod, the slack adjuster turns the camshaft, and the S-cam presses the shoes against the drum
Explanation: Air entering the brake chamber moves the pushrod. The pushrod and slack adjuster rotate the camshaft so the S-cam forces the brake shoes against the inside of the drum.
5During the Utah CDL air-brake check, when must the low-air warning devices activate?
A.Before pressure drops below 55 psi
B.At the same pressure as normal governor cut-in
C.Only when the parking brake valve pops out
D.After pressure drops below 20 psi
Explanation: The current Utah CDL handbook requires the buzzer, light, and flag, if equipped, to activate before pressure drops below 55 psi. This warning comes well before the emergency or parking brake valve should pop out.
6What does the 'slippery' setting on an older front-brake limiting valve do?
A.It sends full pressure to the front brakes and half pressure to the rear brakes
B.It reduces pressure to the front brakes, but the handbook advises using the normal position for best stopping control
C.It prevents the compressor from reaching governor cut-out on wet roads
D.It applies the spring brakes on the steering axle before a skid begins
Explanation: On older vehicles, the slippery setting cuts the normal air pressure to the front brakes by half. The handbook explains that reducing front-brake force is not helpful because front-wheel braking contributes to stopping control, so the normal setting should be used.
7What normally happens as air pressure falls into the manufacturer-specified 20-to-45 psi range?
A.The compressor reaches governor cut-out
B.The low-air warning first becomes permissible
C.The service brakes release to conserve the remaining air
D.The emergency or parking brake valve closes and the spring brakes apply
Explanation: As pressure falls to the manufacturer's specified level, normally within 20 to 45 psi, the emergency or parking brake valve closes and the spring brakes apply. A driver should stop safely while enough air remains for controlled service braking.
8How is the yellow, diamond-shaped parking brake control normally operated?
A.Pull it out to apply the parking brakes and push it in to release them
B.Push it in to apply the parking brakes and pull it out to release them
C.Turn it clockwise to apply only the trailer service brakes
D.Hold it halfway out to test the low-air warning devices
Explanation: Pulling the parking brake control out exhausts air from the spring-brake chambers and applies the brakes. Pushing it in supplies air to release the spring brakes when adequate pressure is available.
9Why should a driver avoid pressing the service brake pedal when the spring brakes are already applied?
A.It can make the compressor cut in below its specified pressure
B.It can combine spring and service-brake forces and damage brake components
C.It automatically changes a dual air system into a single air system
D.It prevents the low-air warning light from completing its bulb check
Explanation: Applying the service brakes while the spring brakes are on can compound the forces acting on the brake mechanism. The handbook warns that this combined force can damage brake components.
10Which vehicles does the Utah CDL handbook identify as subject to the late-1990s federal air-brake ABS requirements?
A.Only school buses built after March 1, 1998
B.Only truck tractors and trailers built after March 1, 1997
C.Truck tractors built on or after March 1, 1997, and other air-braked vehicles built on or after March 1, 1998
D.Every air-braked vehicle regardless of its manufacture date
Explanation: The handbook states that truck tractors built on or after March 1, 1997, and other air-braked vehicles built on or after March 1, 1998, must have ABS. Older vehicles may have ABS, but those dates do not make every earlier vehicle subject to the same requirement.

About the Utah CDL Air Brakes Exam

The Utah CDL Air Brakes knowledge test is a 25-question examination administered by the Utah Driver License Division (DLD) for commercial drivers who intend to operate commercial motor vehicles equipped with air brakes. Testing is conducted in English only; translation materials are strictly prohibited. The test covers Section 5 of the Utah CDL Handbook: compressor and governor operation, reservoirs, safety valves, foundation brakes, dual systems, low-pressure warnings, spring brakes, ABS, and air-brake inspection checks. Failing the knowledge test or testing in a vehicle without the applicable full-air system produces an L or Z restriction. Independent OpenExamPrep practice offers four-option study questions and does not replace vehicle inspection or driving-skills practice.

Exam sponsor: Utah Department of Public Safety (DPS) Driver License Division (DLD). The requirements and fees below concern the certification or admission exam, separate from our free practice resources.

Assessment

A 25-question multiple-choice knowledge examination administered on computer in English only at Utah DLD offices covering Section 5 of the Utah Commercial Driver License Handbook. Passing this test and demonstrating pre-trip air-brake checks during the skills test avoids the L restriction (no full air brakes).

Time Limit

Not published by Utah DLD

Passing Score

At least 80% correct (20 of 25 questions) under Utah DLD and 49 CFR 383.135

Exam / Certification Fees

$52 application fee includes two written-test attempts; two additional written-test attempts cost $26

Exam sponsor website

Fees, eligibility, and exam policies can change. Confirm them with the exam sponsor before applying or paying.

Official sources

Our practice resources: topics covered

We aim to reflect publicly available exam outlines and topic information in our study resources. Coverage, format, and difficulty may differ from the actual exam, and we cannot guarantee that every detail is accurate or current. Confirm exam requirements, fees, and policies with the official exam sponsor.

Utah CDL Handbook Sections 5.1.1 to 5.1.13 (official weight not published)

Air Brake System Parts

Three brake systems (service, parking, emergency); compressor and governor (cut-in ~100 psi, cut-out ~120-140 psi); air storage tanks, manual and automatic drain valves, alcohol evaporators, safety relief valve (150 psi), foot valve, foundation brakes, pressure gauges, low-air warning devices, and stop-light switches.

Utah CDL Handbook Sections 5.1.14 to 5.1.15 (official weight not published)

Spring Brakes and Parking Controls

Mechanical spring brakes held back by air pressure, automatic spring brake application when air pressure drops to 20-45 psi, yellow diamond push-pull parking brake knob, compounding forces, and modulating control valves.

Utah CDL Handbook Sections 5.1.16 and 5.4.2 (official weight not published)

Antilock Braking Systems (ABS)

Federal ABS mandate dates, yellow ABS malfunction indicator lamps, electronic control units, maintaining steering control during emergency stops, and proper braking technique with ABS.

Utah CDL Handbook Section 5.2 (official weight not published)

Dual Air Brake Systems

Primary and secondary pneumatic circuits, separate tanks and lines sharing a common brake pedal, minimum 100 psi operating pressure, and safe stopping procedures if one circuit suffers pressure loss.

Utah CDL Handbook Section 5.3 (official weight not published)

Inspecting Air Brake Systems

Pre-trip air brake inspection steps: compressor drive belt/gear, manual slack adjuster pushrod travel (no more than 1 inch), brake drum/rotor inspection, pressure buildup rate, governor cut-in/cut-out, static leakage, applied leakage, low-pressure warning test, and spring brake pop-out test.

Utah CDL Handbook Section 5.4 (official weight not published)

Using Air Brakes

Normal stopping procedures, brake lag distance, controlled braking vs stab braking, proper downgrade braking technique on Utah mountain passes (selecting correct low gear, snub braking: braking until 5 mph below safe speed, then releasing), brake fade and heat buildup, and parking brake use.

Preparing for the Utah CDL Air Brakes Exam

What You Need to Know

  • Passing score: At least 80% correct (20 of 25 questions) under Utah DLD and 49 CFR 383.135
  • Assessment: A 25-question multiple-choice knowledge examination administered on computer in English only at Utah DLD offices covering Section 5 of the Utah Commercial Driver License Handbook. Passing this test and demonstrating pre-trip air-brake checks during the skills test avoids the L restriction (no full air brakes).
  • Time limit: Not published by Utah DLD
  • Exam / certification fees: $52 application fee includes two written-test attempts; two additional written-test attempts cost $26 Official sources

Using Our Practice Resources

  • Work through all 150 available questions
  • Review every answer and explanation
  • Track weak areas and revisit them
  • Use our AI tutor for tough concepts

Utah CDL Air Brakes: Suggested Study Strategy

1Memorize the maximum air leakage limits: static test is 2 psi/min (single) or 3 psi/min (combo); applied test is 3 psi/min (single) or 4 psi/min (combo).
2Learn the key pressure checks: use the manufacturer's governor cut-out specification, verify the low-air warning before pressure falls below 55 psi, and know the manufacturer-specified 20-to-45-psi emergency-brake pop-out range.
3Understand brake lag: the time needed for air to flow through the lines can add about 32 feet of stopping distance at 55 mph.
4Master downgrade snub braking: brake until 5 mph below safe speed, then release. Never ride the brakes down steep Utah mountain passes.

Frequently Asked Questions

What is the Utah CDL Air Brakes test and who must take it?

The Air Brakes knowledge test is a 25-question examination administered by Utah DLD. Any commercial driver who plans to drive a commercial vehicle equipped with air brakes must pass this test (and take the skills test in an air-braked vehicle) to avoid having the L restriction (no full air brakes) placed on their CDL.

What is the passing score for the Utah Air Brakes knowledge test?

The test contains 25 multiple-choice questions. Under Utah DLD rules and 49 CFR 383.135, you must score at least 80% (answering at least 20 questions correctly) to pass. Testing is closed-book, multiple-choice, and in English only.

What are the acceptable air leakage rates during the pre-trip inspection?

With the engine off and brakes released (static leakage test), the maximum allowable air loss is 2 psi per minute for single vehicles and 3 psi per minute for combination vehicles. With the service brakes firmly applied (applied leakage test), the maximum allowable air loss is 3 psi per minute for single vehicles and 4 psi per minute for combination vehicles.

At what air pressure must the low air pressure warning device activate?

Under the current Utah CDL handbook, the low-air warning buzzer, light, and flag, if equipped, must activate before pressure drops below 55 psi.

At what pressure do spring brakes automatically apply?

Spring brakes are held back by air pressure. If air pressure drops to a range between 20 and 45 psi (typically 20 to 30 psi), the air pressure will no longer overcome the spring pressure, and the spring brakes will automatically pop out and apply.

What is the proper technique for braking on steep downgrades in Utah?

Shift into a low gear before starting down the grade. Once your vehicle reaches your 'safe speed', apply the service brakes firmly enough to feel a definite slowdown until your speed drops 5 mph below your safe speed, then release the brakes completely. Repeat this 'snub braking' process as speed builds back up. This allows brake drums to cool and prevents deadly brake fade.

How much does the Air Brakes test cost in Utah?

Utah DLD includes two written-test attempts in the $52.00 CDL application fee. Two additional written-test attempts cost $26.00. A DLD commercial skills test costs $78.00 for two attempts, with two additional attempts costing $52.00.

Are these practice questions identical to the official Utah DLD test?

No. These are independent educational study questions based on the Utah CDL Handbook and FMCSA regulations. They do not duplicate official exam items or replace hands-on pre-trip inspection practice.