Air Brakes #2
Air Brakes Endorsement Test | District Of Columbia 2025 #2 Page 3 of 4
Train for FREE online with our District Of Columbia CDL air brake test. The official exam test consists of several obligatory parts, with all of them checking your knowledge of different blocks of road rules. If you need to obtain a DC Class A/Class B driver license in 2025, practice as much as possible. Free sample tests published on our website will help you check and improve your knowledge and boost your grades. Please bear in mind that the requirements for CDL may vary from state to state.
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13 . What does the air compressor governor do?
Controls the temperature of the air leaving the air storage tanks.
In an air brake system, the air compressor governor controls when the air compressor pumps air into the air storage tanks.
14 . When inspecting your brakes, a slack adjuster should move ____ from where it is attached to the push rod.
No more than one inch
Check each slack adjuster after 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.
15 . A modulating control valve can control the:
Anti-lock braking system (ABS).
A modulating control valve allows a driver to gradually apply spring brakes. In equipped vehicles, the valve is controlled by a lever located on the dashboard.
16 . When traveling down a steep downgrade, the best way to use your brakes is to:
Apply consistent pressure to the brake pedal all the way down the hill.
On a long or steep downgrade, brakes should only be used to supplement the braking effect of the engine. Apply the brakes just enough to feel a definite slowing down, then release them once you are about 5 mph below your target "safe" speed. Once your vehicle reaches its safe speed again, repeat this process.
17 . What can happen if parking brakes are used in very wet weather with temperatures below freezing?
The brakes may become too smooth to be used.
Parking brakes should not be used in very wet weather when temperatures are below freezing. The brakes could become frozen in place, making it impossible to move the vehicle.
18 . Most heavy-duty vehicles use:
Quadruple air brake systems.
Most heavy-duty vehicles use dual air brake systems, in which there are two separate braking systems operated by a single set of controls. Each system operates the brakes on different axles.
2025 District Of Columbia | Frequently Asked Questions
In the District of Columbia, a CDL Class A license allows the holder to operate any combination of vehicles with a Gross Combination Weight Rating (GCWR) of 26,001 pounds or more, provided the Gross Vehicle Weight Rating (GVWR) of the vehicle(s) being towed is over 10,000 pounds. This includes tractor-trailers, truck and trailer combinations, and flatbeds.
A Class A CDL license in the District of Columbia permits the holder to operate various types of larger, heavier commercial vehicles. This includes tractor-trailers, truck and trailer combinations, tank vehicles, livestock carriers, and flatbeds. The vehicles can have a Gross Combination Weight Rating (GCWR) of 26,001 pounds or more if the towed vehicle is over 10,000 pounds.
To obtain a Class A CDL license in the District of Columbia, you must be at least 21 years old, possess a valid non-commercial driver's license, pass a vision test, and provide proof of residency and identity. You'll also need to pass written knowledge tests, obtain a Commercial Learner's Permit (CLP), and successfully complete a skills and road test.
In the District of Columbia, you must be at least 21 years old to qualify for a Class A Commercial Driver's License (CDL). This age requirement is consistent across all states and is set by federal regulation. This allows for interstate operation of commercial vehicles. For intrastate (within the same state), the minimum age can be 18.
Specific endorsements are not required for a Class A CDL license but they can provide additional driving privileges. These include endorsements for operating vehicles like school buses, passenger vehicles, tank vehicles, and vehicles carrying hazardous materials. Each endorsement requires passing specific knowledge and skills tests.
The Class A CDL skills test in the District of Columbia consists of three parts: the vehicle inspection test, the basic control skills test, and the road test. The vehicle inspection test involves checking the vehicle's safety components, the basic control skills test assesses your ability to maneuver and control the vehicle, and the road test evaluates your on-road driving skills.
Yes, limitations can be imposed on Class A CDL license holders in the form of restrictions. These are based on the driver's abilities or the type of vehicle they tested in. For example, if a driver takes the skills test in an automatic transmission truck, they will have an 'E' restriction, limiting them to automatic transmission vehicles only.
Yes, it is possible to take the written Class A CDL test in languages other than English in the District of Columbia. However, the Federal Motor Carrier Safety Administration requires all CDL holders to read and speak English sufficiently to converse with the general public, understand highway traffic signs and signals, respond to official inquiries and make entries on reports and records.
Yes, you can request accommodations for the Class A CDL written test in the District of Columbia due to disability. The DMV is committed to providing accessible services and accommodations to individuals with disabilities. You should contact the DMV directly in advance of your test to discuss your needs and the potential accommodations available.
If you don't pass the Class A CDL written test in the District of Columbia, you are allowed to retake it. However, you must wait three days before retaking the test. If you fail the test three times, you must wait 90 days before taking it again. There's also a retesting fee that applies each time.