Georgia CDL — Air Brakes practice
Georgia CDL — Air Brakes: Handling Emergencies practice test
What to do when things go wrong — brake failure, tire blowouts, skids, and stalling on railroad tracks.
Content reviewed against official driver handbooks · August 12, 2026
13 questions · pass with 10 correct. You get instant feedback and an explanation after every answer.
Study questions with answers
12 sample Handling Emergencies questions with the correct answer, a short explanation, and the official handbook reference. Read through them, then take the quiz above.
Show all 12 questions with answers
1. What is the main cause of brake fade on a long downgrade?
Correct answer: Excessive heat from using the brakes too much instead of engine braking
Relying on the service brakes instead of engine braking causes excessive heat. Overheated drums expand and linings lose friction, so the brakes provide less and less stopping power — and severe overheating can cause permanent damage.
2. Your brakes have overheated and are failing partway down a mountain grade, and an escape ramp is marked ahead. What should you do?
Correct answer: Use the escape ramp — it is built to stop runaway vehicles safely
Escape ramps use loose material or an upgrade to stop a runaway vehicle safely. If your brakes fail on a downgrade, use the escape ramp — it greatly reduces the chance of injury and vehicle damage compared to any alternative.
3. Some dash-mounted control handles let you put the spring brakes on a little at a time. Why is that gradual action useful?
Correct answer: It lets you meter the spring brakes yourself if the service brake system quits
A modulating valve is spring-loaded, so the farther you move the lever the harder the spring brakes grab. That feel lets a driver hold the vehicle under control by hand when the normal foot-brake system has failed.
4. Why should you avoid pressing the brake pedal down while the spring brakes are applied?
Correct answer: The combined spring and air pressure forces could damage the brakes
The forces of the springs and the service brake air pressure can add together and damage the brakes. Many vehicles have valves to prevent this, but you should not rely on them.
5. While you are driving, pressure in one half of your dual air brake system falls very low. What should you expect from the vehicle?
Correct answer: One end of the vehicle will brake poorly, so you need more room to stop
Each half of a dual system feeds different axles. When one half loses most of its pressure, the axles it serves stop doing their share of the work and stopping takes noticeably longer. Park somewhere safe and get the fault repaired before driving on.
6. You always drive a straight truck whose antilock system is working on every axle. In a genuine emergency stop, this permits you to:
Correct answer: Push the brake pedal all the way to the floor
As a rule you brake the same way whether or not antilock brakes are fitted. The single exception is a driver whose vehicle has a working antilock system at each axle: in an emergency that driver may push the pedal to the floor and let the computer prevent lockup.
7. The emergency stopping power of your spring brakes depends most directly on:
Correct answer: The service brakes being in proper adjustment
Spring brakes act through the same service brake components. If the service brakes are out of adjustment, neither the emergency nor the parking function will work properly — another reason adjustment checks matter.
8. Before starting down a long, steep hill in a heavy vehicle, you should:
Correct answer: Shift into a low gear so engine braking helps control your speed
Shift into a low gear before starting downhill and let the engine's braking effect do the primary work of holding your speed. Brakes are then used only to keep you at or below your safe speed.
9. Only the tractor of your combination has antilock brakes. During a hard stop you see the trailer beginning to swing out. What does the manual tell you to do?
Correct answer: Ease off the brake pedal, provided doing so is safe
An antilock system on the tractor alone protects your steering but does nothing for the trailer. Watching what the trailer is doing and backing off the pedal — as long as easing up is safe — is what brings it back into line.
10. While driving, the low air pressure warning buzzer suddenly sounds. Your best response is to:
Correct answer: Stop and safely park as soon as you can, while braking is still controllable
The warning means pressure is dropping and the spring brakes could soon apply on their own. Stop and safely park as soon as possible, while you still have controlled braking available.
11. A bus fitted with dual parking control valves has lost its main air supply, and the spring brakes have set. Why should you plan your move before pushing the release control in?
Correct answer: The reserve tank is good for only a few releases before it empties
The backup tank on such vehicles stores just enough air for a handful of spring-brake releases. Choose where you are going first, or the reserve can run dry and leave the bus stopped in a hazardous spot.
12. If a leak drains your air tanks while you are on the road, at roughly what pressure will the spring brakes apply by themselves?
Correct answer: 20 to 45 psi
Spring brakes come fully on when air pressure drops into the 20 to 45 psi range (typically). By then you may lose steering-friendly, controlled braking — which is why you must stop when the warning first activates.
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