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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.
upshift.
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 brakes built after 2009.
 
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Frequently Asked Questions

If you are between 14½ and under 17 years old you must follow the Graduated Driver Licensing (GDL) Program. You can apply for a supervised instruction permit and complete an approved driver training program. After 6 months of violation-free supervised driving, you can apply for a restricted driver’s license (it will be restricted until your 18th birthday).

If you are 17 or older you can apply for a class D instruction permit and after six months of supervised driving, you can obtain a class D driver’s license.

To schedule the DMV written test in Idaho, you can visit your county Sheriff’s DMV office in person. Find the Idaho DMV office nearest to you and check its business hours.

You are required to bring the following documents:
  • Proof of identity and age.
  • Photo ID.
  • Proof of Idaho residency.
  • Social Security Card.
  • Proof of US citizenship or legal presence.
  • Driver training completion certificate (for applicants under 17).
  • Liability Signer (for those under 18, a parent or guardian must sign consent for licensing).
  • Proof of school enrollment (for those under 18).

Additionally, if applicable:
  • Foreign driver’s license.
  • Medical certification (if you have a medical condition that may affect your ability to drive).

Use the tool provided by the Idaho Transportation Department to create a checklist of the necessary documents.

The DMV written test in Idaho is offered in various languages, including English, Arabic, Chinese, Farsi, French, Korean, Russian, Servo-Croatian, Spanish, Vietnamese and ASL (American Sign Language). Although language options are provided, it is advisable to have a basic understanding of English since road signs are always in English.
The DMV written test covers various topics, such as road signs, parallel parking, turning, passing a vehicle, yielding the right of way, etc. Studying the official Idaho Driver’s Handbook is the first step to prepare for the exam because it contains all of this information. Once you've read it, you can take our free practice tests!
The Idaho DMV written test consists of 40 questions and is based on the information provided in the manual. Taking numerous practice tests and thoroughly reading the handbook will increase your chances of success.

You are allowed to miss up to 6 questions, with a minimum accuracy rate of 85%. Using any written, audio, or electronic aid is forbidden.

New drivers in Idaho are subject to specific restrictions:

  • If you are younger than 16, you can drive only during daylight hours, except when accompanied by a licensed driver aged at least 21, who must be seated beside you.  Additionally, you cannot transport any other passengers
  • If you are under 17, during the first six months from the date the license was issued, you can only transport one passenger under 17 or family members.
  • If you are under 21, you cannot drive after drinking any amount of alcohol (Zero Tolerance law).
An Idaho instruction permit remains valid for 180 days after successfully completing a driver training program and the GDL Program. You can renew the permit once without retaking the knowledge test, as long as you took it within the past 12 months.
If you fail your DMV written test, you must wait three days to retest and pay another application fee. Sign up for DMV Premium and practice with extra tests to maximize the chance of passing!

ID CDL Air Brakes Test

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