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 pounds To receive this license, applicants must pass a 50-question.. 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. To pass, applicants must answer 40 questions correctly. Each question has three possible answer choices. Test questions come from the New Mexico Commercial Driver License Manual. Questions come from chapters covering: Introduction, Driving Safely, Transporting Cargo Safely, Air Brakes (if applicable), Combination, Doubles and Hazardous Materials. Endorsements that may be used with a Class A CDL are: Hazardous materials, Tank, Passenger, HazMat and Tank, Air Brakes and School bus.

Number of Question
Passing Score

1. If the safety relief valve in an air brake system is releasing air:

Explanation
The safety relief valve in an air brake system releases air if necessary to prevent pressure in the system from becoming too high. If the valve starts releasing air, there is something wrong. Have a mechanic fix the problem.

2. Without the proper amount of oil in its engine:

Explanation
It is essential that a vehicle's engine have adequate oil pressure. An engine can be destroyed rapidly if it is run without oil.

3. A vehicle that is smaller than your vehicle:

Explanation
In general, a smaller vehicle will be able to come to a complete stop faster than a larger vehicle. Keep this in mind when determining your following distance.

4. A tread depth of ____ should be in every major groove of a front tire.

Explanation
For safe operation, a commercial motor vehicle needs a tread depth of 4/32 of an inch in every major groove on the front tires, and a tread depth of 2/32 of an inch on other tires.

5. During an inspection, slack adjusters on S-cam brakes should not move more than:

Explanation
Check each slack adjuster after parking on level ground, setting wheel chocks, and disengaging the parking brake. Pull the slack adjusters to make sure they do not move more than about one inch from where the push rod is attached. If they move more than one inch, they may be out of adjustment and will need to be fixed.

6. The leakage rate for a triple combination vehicle with air brakes should be no more than ____ in one minute during a static leakage test.

Explanation
When performing a static leakage test on a triple combination vehicle with air brakes, the leakage rate should be no more than 5 psi in one minute. If the air leaks from the air brake system at a quicker rate, the vehicle should not be driven because something likely needs to be repaired.

7. If there is a fire in your vehicle, you should not:

Explanation
In the event of a vehicle fire, you should leave the road and stop in an open area. Do not pull into a service station as fuels at the service station could catch fire. Report the fire and your location to emergency services.
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