Knowledge Test Class A

This license is required for driving any legal combination of vehicles, with a gross combination weight rating of 26,001 pounds or more, provided the GVWR of a trailer exceeds 10,000.. Read More

This license is required for driving any legal combination of vehicles, with a gross combination weight rating of 26,001 pounds or more, provided the GVWR of a trailer exceeds 10,000 pounds. To receive this license, applicants must pass a 50-question test. Test questions come from the Ohio Commercial Drivers License Manual. To pass, applicants must answer 40 questions correctly. Questions come from chapters covering: Introduction, Driving Safely, Transporting Cargo Safely, Air Brakes (if applicable), Combination Vehicles, Pre-Trip Vehicle Inspection Test, Basic Vehicle Control Skills Test and On-Road Driving. Endorsements that may be used with a Class A CDL are: Hazardous materials, Tank, Passenger, Doubles/Triples, HazMat, Tank, Air Brakes and School bus.

Number of Question
Passing Score

1. Which of the following is not a cause of hydraulic brake failure?

Explanation
Most cases of hydraulic brake failure come from one of two causes. The brakes may fail due to a loss of hydraulic pressure or due to overuse on long hills, causing the brakes to fade.

2. When backing a truck, you should:

Explanation
When backing a truck, always use the mirrors on both sides of the vehicle. Have someone help you whenever possible.

3. To prevent your vehicle from rolling backward when beginning to move, you can:

Explanation
To ensure that your vehicle does not roll backward when beginning to move after a stop, you should partly engage the clutch before removing your right foot from the brake pedal.

4. If you realize you may be running late to your destination, you should:

Explanation
To reduce the risk of developing aggressive driving behavior, you should take measures to manage your stress. One strategy to do this is to simply take a deep breath and accept your circumstances if you realize you will be late to your destination.

5. Regrooved tires:

Explanation
Regrooved, recapped, or retreaded tires are prohibited on the front wheels of a bus.

6. What tells you how much pressure is in your vehicle's air tanks?

Explanation
A vehicle that is equipped with air brakes must also be equipped with a supply pressure gauge. This gauge tells the driver how much air pressure is in each of the vehicle's air tanks.

7. What should you do if your vehicle gets stuck on railroad tracks?

Explanation
If your CMV gets stuck on railroad tracks, you should immediately leave the vehicle and get away from the tracks. Check the signposts or signal housing at the crossing for emergency contact information and call 911, or another appropriate emergency number.
DMV Writen Test Logo