Air Brakes #1
Air Brakes Endorsement Test | District Of Columbia 2026 #1 Page 2 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 2026, 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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7 . If braking at a speed of 55 mph while driving on dry pavement, the brake lag can add ____ to your vehicle's total stopping distance.
10 feet
The total stopping distance for vehicles equipped with air brakes is made up of four factors: perception distance, reaction distance, brake lag distance, and braking distance. When braking at a speed of 55 mph while driving on dry pavement, the brake lag can add around 32 feet to a vehicle's total stopping distance.
8 . When only the tractor is equipped with an Anti-Lock Braking System (ABS):
The brakes will become more sensitive.
If a tractor is equipped with an Anti-Lock Braking System (ABS) but the trailer is not, the risk of jackknifing will be reduced and the driver should still be able to maintain steering control. If only the trailer is equipped with ABS, it is less likely that the trailer will swing out to one side.
9 . All air tanks must include:
A warning sticker.
Air brake system tanks must contain drain valves. These valves are used to drain accumulated oil and water from the tanks and may be either manually or automatically operated.
10 . 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.
11 . The brake pedal is part of which braking system?
The auxiliary brake system
The service brake system applies and releases the brakes when a driver presses the brake pedal while driving normally.
12 . Service brakes should:
Before driving, you should always verify that your service brakes are in good working order. Testing the brakes before a trip allows you to locate any problems before you need to brake while on the road.
2026 District Of Columbia | Frequently Asked Questions
To acquire a CDL Hazmat endorsement in the District of Columbia, you must first hold a valid CDL. Then, pass the Hazardous Materials Knowledge Test at a DMV service location. You'll also need to undergo a federal TSA background check and fingerprinting. Lastly, submit the Hazmat Endorsement Application, proof of U.S. citizenship or legal status, and pay the required fees.
To obtain a CDL Hazmat license, you must already hold a valid Commercial Driver's License (CDL). You also need to pass the Hazardous Materials Knowledge Test, undergo a federal TSA background check, and be fingerprinted. Proof of U.S. citizenship or legal status is required. Lastly, you need to be in good physical health to meet the demands of the job.
When applying for a CDL Hazmat endorsement, you'll need to provide your valid Commercial Driver's License (CDL), proof of U.S. citizenship or legal residency (like a passport or birth certificate), and proof of identity. You'll also need to bring the receipt for your TSA background check and fingerprinting, and complete the Hazmat Endowment Application.
Yes, there is a dedicated written test for the CDL Hazmat endorsement. This test focuses on the rules and safety procedures for handling and transporting hazardous materials. It's essential to study the Hazmat section of your state's CDL manual thoroughly before taking the test to ensure you're well-prepared.
The written test for the CDL Hazmat endorsement covers a range of topics related to hazardous materials. These include identifying hazardous materials, understanding shipping papers, using placards and labels, handling emergencies, loading and unloading procedures, and complying with the relevant safety rules and regulations.
Yes, there are extra charges associated with acquiring a CDL Hazmat endorsement. These include fees for the TSA background check and fingerprinting, which typically cost around $86.50. Additionally, there may be a fee for the endorsement application, which varies by state. It's best to check with your local DMV for specific costs.
Yes, obtaining a CDL Hazmat endorsement requires a mandatory background check and fingerprinting conducted by the Transportation Security Administration (TSA). This ensures the individual doesn't pose a security threat and is part of the federal safety regulations for handling hazardous materials.
Yes, specialized training is mandatory for the CDL Hazmat endorsement. Applicants must pass a written test that covers the regulations and requirements for transporting hazardous materials. After passing the test, they receive a certification, which is the Hazmat endorsement on their Commercial Driver's License (CDL). This ensures they are knowledgeable about handling hazardous materials safely.
No, you cannot legally transport hazardous materials without a valid CDL Hazmat endorsement. This endorsement ensures that you have the necessary knowledge and skills to handle hazardous materials safely. Driving without it can result in serious penalties, including fines and suspension of your commercial driver's license.
Yes, you can add a Hazmat endorsement to your existing CDL. You don't need to apply for a new CDL. However, you must pass a written Hazmat knowledge test, submit to a TSA background check, and pay the associated fees. Once these steps are completed successfully, the Hazmat endorsement will be added to your CDL.