Knowledge Test Class B #1
Class B Driving Test | District Of Columbia 2026 #1 Page 6 of 7
Train for FREE online with our District Of Columbia class B license 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 CDL class B permit 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 CDL class B requirements may vary from state to state.
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36 . While driving, spring brakes are generally held in place by:
Sturdy ties.
While driving, spring brakes are generally held in place by air pressure. If the air pressure gets low enough, the springs will activate the brakes.
37 . To make driving at night easier, you should:
Use only your low beam headlights.
If the interior of your cab is too bright when you are driving at night, you may have difficulty seeing things outside. Keep the interior light off and adjust your instrument lights to the lowest possible level that still allows you to easily read the gauges.
38 . Which of the following is not an example of a driving hazard?
An ice cream truck
Passing an accident scene can be hazardous because the people involved in the accident may not be watching traffic, and the scene itself may distract other passing drivers. Ice cream trucks can create hazardous conditions because they attract children who may not pay attention to nearby vehicles. Shoppers near the roadway are often paying attention to stores, not passing traffic.
39 . Which of the following is a good rule to follow when making a turn?
Signal early.
Signal well in advance of a turn so drivers behind you are aware of your intentions. Keep the signal on throughout the turn and turn it off once the turn is complete.
40 . During the vehicle inspection test, you will be asked to:
Change a windshield wiper.
During the CDL vehicle inspection test, you must be able to inspect your vehicle and explain to the examiner what you are inspecting and why.
41 . You may be denied a HazMat endorsement if:
You do not suffer from a mental illness.
You will be denied a HazMat endorsement, or lose an existing endorsement, if you are not a lawful permanent U.S. resident; you renounce your U.S. citizenship; you are wanted for, under indictment for, or convicted of certain felonies; you are judged as mentally unstable or are committed to a mental institution; or you are deemed to pose a security threat by the Transportation Security Administration (TSA).
42 . What should happen if the air pressure in the braking system's air tanks falls below 60 psi?
The steering wheel will lock up.
On vehicles with air brakes, a low air pressure warning signal will come on if the pressure in the air tanks falls below 60 psi. On large buses, the signal may activate at 80 to 85 psi.
2026 District Of Columbia | Frequently Asked Questions
In the District of Columbia, you can acquire a CDL Tank endorsement by first holding a valid CDL. You need to pass the Tank Vehicle written test, which covers topics like inspecting tank vehicles, driving tank vehicles, and safe driving rules. After passing the test, you pay the required fee to add the endorsement to your CDL.
To obtain a CDL Tank license in the District of Columbia, you must first have a valid Commercial Driver's License (CDL). Then, you must take and pass the Tank Vehicle written test, which covers topics such as inspecting and driving tank vehicles, and safe driving rules. After passing, pay the necessary fee to add the endorsement to your CDL.
While the District of Columbia doesn't explicitly require specific training or experience for a CDL Tank endorsement, it's highly recommended. Understanding how to safely operate tank vehicles is crucial. Passing the Tank Vehicle Endorsement Knowledge Test requires knowledge of tank vehicle operations, so training or experience can be beneficial in passing the test.
Yes, for a CDL Tank endorsement in the District of Columbia, you must pass the Tank Vehicle written test. This exam covers important topics like inspecting tank vehicles, driving tank vehicles, and safe driving rules. Passing this test is crucial to demonstrate your knowledge and understanding of operating tank vehicles safely.
The written test for the CDL Tank endorsement in the District of Columbia covers a variety of subjects. These include inspecting tank vehicles, driving tank vehicles, and understanding the unique handling characteristics of tank vehicles. It also tests knowledge on safe driving rules and regulations specific to tank vehicles.
During the CDL Tank endorsement assessment, several skills and maneuvers are assessed. These include inspecting the tank vehicle for safety, demonstrating proper loading and unloading procedures, controlling the vehicle's speed and position, performing backing maneuvers, and executing turns and lane changes safely. Additionally, candidates are evaluated on their ability to handle emergency situations and demonstrate knowledge of hazardous materials regulations.
Drivers with a CDL Tank endorsement in the District of Columbia must comply with specific federal and state regulations. These include restrictions on maximum driving hours to prevent fatigue, mandatory rest periods, and stringent vehicle inspection requirements. Additionally, they must follow rules related to the transportation of hazardous materials if their tank vehicle is used for such purposes.
No, a valid CDL Tank endorsement is required to legally transport liquid or gas materials in the District of Columbia. This endorsement is necessary due to the unique handling and safety requirements associated with transporting such materials. Violating this requirement can result in significant penalties, including fines and suspension of driving privileges.
You can add the CDL Tank endorsement to your existing Commercial Driver's License (CDL) without needing a fresh application. However, you will need to pass a written knowledge test specific to tank vehicles and pay the necessary endorsement fee. Remember, additional endorsements may require further testing.
Yes, to handle hazardous materials with a CDL Tank endorsement, you must also obtain a Hazardous Materials (HazMat) endorsement. This requires passing an additional written test and undergoing a federal background check. Also, adherence to specific regulations regarding the transportation and handling of such materials is mandatory.