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District Of Columbia CDL Permit Test - Air Brakes

Number of questions: 25
Passing score: 20
Directions: This endorsement is required for driving a vehicle with air brakes. To receive this endorsement, applicants must pass a written test. The test consists of 25 multiple choice questions. Each question has four answer choices. To pass, the applicant must answer at least 20 questions correctly. Test questions come from the Washington D.C. Commercial Driver License Manual. Questions come from the chapter covering: Air Brakes. The Air Brakes endorsement may be used with the Class A, B or C CDL.
You have made error so far
Passing grade —
5 or fewer errors
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1.
A tank endorsement is:
Only required when transporting gases.
Only required when transporting liquids.
Required when transporting both liquids and gases.
Optional when transporting hazardous materials.
2.
Pressing and releasing a brake pedal unnecessarily can:
Release air faster than it can be replaced.
Add more air to the braking system.
Make the brake pedal more sensitive.
Create a loud noise.
3.
If one air system in a dual air brake system is very low on pressure:
None of the brakes will work at all.
Either the front or rear brakes will not be operating fully.
There will be no noticeable affect.
Lights on the outside of the tractor will flash.
4.
To confirm that a trailer has ABS, you can:
Look under the trailer for wheel speed sensors coming from the back of the brakes.
Look under the hood for the ABS sticker.
Look at the tires.
Remove a tire and look for the ABS sensor on the axle.
5.
On trucks and buses, where are ABS malfunction lamps located?
On the driver’s door
On the instrument panel
On the outside of the vehicle by the passenger’s door
Under the hood
6.
What kind of force must emergency brakes use?
Air pressure
Mechanical
Heavy
Electrical
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