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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 Ohio CDL knowledge test. The OH 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 Ohio CDL Manual. Take this OH CDL practice test now to prepare for the actual air brakes test!
1. Why should you check your mirrors regularly to know where other vehicles are around you?
To know whether you can make a quick lane change in an emergency.
To move out of their way if they want to get past.
To flash the brake lights if you are being tailgated.
2. If your truck catches fire, the first thing you should do is to:
get the vehicle off the road and park near other vehicles.
pull off the road and park in an open area.
pull into a service station and call for help.
3. The total stopping distance for vehicles with air brake systems is made up of __ different factors.
3
4
2
4. You should NOT use the parking brakes if:
the brakes are cold.
the brakes are very hot.
the brakes are too dry.
5. If you get stuck on railroad tracks, you should:
have a helper push your vehicle.
get out of the vehicle and away from the tracks.
stay in the vehicle and call for help.
6. With the air pressure built up to governor cutoff, the maximum leakage rates per minute are ___ psi for single vehicles and ___ psi for a combination of 2 vehicles.
5; 6
3; 2
3; 4
7. It is not safe to drive a vehicle that has brake drums with cracks that are longer than ___ the width of the friction area.
1/4
1/2
3/5
8. Stepping on and off the brake pedal several times:
reduces the air pressure in the tanks.
may cause air leaks.
may result in dangerously thin linings.
9. The wig wag is:
a low air pressure warning system.
a noise reduction mechanism.
a type of rollover.
10. Supply pressure gauges tell you:
how much air pressure you are applying to the brakes.
when the air pressure in the tanks falls below 60 psi.
how much pressure is in the air tanks.
 
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Frequently Asked Questions

If you are 15 ½, you can get a TIPIC (temporary instruction permit identification card) within 60 days of passing the knowledge and vision tests. After holding the permit for six months and completing your driving instruction, you can apply for a probationary license within 60 days after passing the driving and skills tests. If you're 18 or older, after obtaining the permit, you can obtain a class D driver license without the six-month waiting period.

You have two options:
  • You can visit an Ohio driver exam office. No appointment is required, but check days and business hours of the chosen office.
  • You can take the test online at KnowTo Drive, the official knowledge testing platform. If you are between 15 ½ and 19 years old, you must be supervised by a driver who is at least 19 years old. After passing the test, you are still required to visit a local Ohio BMV office to validate your identity and pass the vision screening.

Applicants can choose between a compliant and a standard license. Ensure you have proof for the following based on your card preference:
  • Full legal name (and proof of name change, if applicable)
  • Date of birth
  • Legal presence in the U.S.
  • Social Security number (SSN)
  • Ohio street address (you'll need two documents for a compliant card and one document for a standard card)

Refer to the acceptable documents list for more information.


The BMV written test is offered in multiple languages, including Arabic, Chinese, English, French, Japanese, Russian, Somali, and Spanish. If you speak another language or are hearing impaired, you may use an interpreter

The BMV written test covers road rules, safe driving practices, and road signs. Studying the official Ohio Digest of Motor Vehicle Laws is the first step to pass the exam because it contains all of this information. Once you've read it, you can take our free practice tests!
The Ohio BMV written test consists of 40 multiple-choice questions and is based on the information provided in the manual. Remember, you have 60 minutes to complete the online test. Taking numerous practice tests and thoroughly studying the handbook will increase your chances of success.

To pass the Ohio BMV written test, you need to reach a score of 75%. This means that you must correctly answer 30 questions and can miss up to 10 questions. Sign up for DMV Premium to test your preparation and check if you are ready for the real exam.

With a permit in Ohio, the following restrictions apply:
  • You must have your permit while driving.
  • If you are under 16, a parent/guardian, or a licensed driving instructor must be in the passenger seat. If you are 16 or older, driving is allowed with any licensed driver over 21 in the passenger seat, except between midnight and 6 a.m. During this time you must be accompanied by a parent, guardian, custodian, or an approved driver aged 21 years or older (form BMV 2438).
  • Everyone in the vehicle must use safety belts.

With a probationary license, these restrictions apply:
  • Driving is prohibited from midnight to 6 a.m., unless accompanied by a parent, guardian, or custodian, or an approved driver aged 21 years or older. Exceptions for driving during restricted hours include employment activities and school-sponsored or religious events (form BMV 2826).
  • You can transport only one non-family member unless accompanied by a parent or guardian.
  • Everyone in the vehicle must use safety belts.
  • The driver is prohibited from using any mobile devices, including cellular phones.
If you are under 18, during the first 12 months of holding a license, you cannot drive from 1 a.m. to 5 a.m., unless accompanied by a parent/guardian or an approved driver aged 21 years or older, authorized by the BMV 2438 form, or for employment activities and school-sponsored or religious events (form BMV 2826).

In Ohio, an instruction permit is valid for a period of one year. If you are under 18, use this time to complete a driver education class (24 hours of instruction and 8 hours of driving time) at a training school and accumulate 50 hours of driving before scheduling the road test to obtain a probationary driver license.

If you don't pass your BMV written test, you'll need to wait for 24 hours before attempting it again. There's no restriction on the number of retests available in person. However, if you opt for the online permit test, you're allowed a maximum of two attempts within a six-month period.

OH CDL Air Brakes Test

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