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The air brakes endorsement applies to applicants who wish to drive a vehicle with air brakes in Class A, B, or C CDL. To drive a vehicle with air brakes, you must pass the air brake component of the Idaho CDL knowledge test. The ID CDL air brakes test consists of 25 questions, and you'll need at least 20 correct answers to pass (80%). The test covers the information found in the air brakes section of the Idaho CDL Manual. Take this ID CDL practice test now to prepare for the actual air brakes test!
1. Do NOT use the parking brakes:
when you leave your vehicle.
if the brakes are very hot.
when you park for less than two hours.
2. How can you tell if your vehicle is equipped with ABS?
Look for yellow ABS malfunction lamps on the instrument panel.
Trailers will have yellow ABS malfunction lamps on the left side.
All of the above.
3. Vehicles with air brake systems take longer to come to a complete stop than vehicles with hydraulic brakes because of:
brake lag.
brake fading.
reaction distance.
4. Air storage tanks:
pump air into the air storage tanks.
use parts of the service brake systems to stop the vehicle in a brake system failure.
hold compressed air for the brakes.
5. When the spring brakes are on, you should never:
change lanes.
push the brake pedal down.
6. The spring brakes come on:
when you bring the vehicle to a complete stop right away.
when main air pressure is lost.
when air pressure in both air brake systems rises to a value set by the manufacturer.
7. Vehicles with air brakes require more stopping distance than vehicles with hydraulic brakes. Why?
Stopping distance for vehicles with air brakes is made up of six different factors.
Air brakes use different brake drums.
It takes one half second or more for the air to flow through the lines to the brakes.
8. Radial and bias-ply tires:
should be used together only when driving in packed snow.
should not be used together.
should be used together.
9. When using a fire extinguisher, you should stay:
as far away from the fire as possible.
as close to the fire as possible, without getting burnt.
at least 10 feet away from the fire.
10. A low air pressure warning signal is required on:
all vehicles with air brakes.
all vehicles with air brakes built after 2005.
all vehicles with air brakesĀ built after 2009.
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ID CDL Air Brakes Test

Number of questions: 25
Correct answers to pass:20
Passing score:80%
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