Knowledge Test Class B #1
Class B Driving Test | District Of Columbia 2026 #1 Page 2 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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8 . If driving in a foggy area, you should not:
Turn on your four-way flashers.
It is safest not to drive in foggy areas. However, if you must drive through fog, you should slow down, use your low beam headlights and fog lights, and turn on your four-way flashers.
9 . What can change the height of a vehicle?
Number of windows
The added weight of a heavy load will make a vehicle sit lower than usual. A vehicle will often be taller when carrying a light load than when carrying a heavy load. If your vehicle fits under an overpass while carrying a full load, it is not guaranteed that it will fit under the same overpass if it is empty.
10 . Most CDL holders have ____ licenses.
Non-exempted
Most CDL holders who drive CMVs in interstate commerce are non-excepted interstate commerce drivers.
11 . A low air pressure warning signal should activate:
When tank pressure falls below 5 psi.
In an air brake system, a low air pressure warning signal must come on if air pressure in the tanks falls below 60 psi. This warning signal may come in the form of a light, a buzzer, or a wig wag.
12 . Belts in the engine compartment should be:
Easy to slide off.
When inspecting your vehicle's engine, check the belts for tightness and excessive wear. The amount of "give" that is safe for each belt in a given engine will vary, so learn what is appropriate for your vehicle.
13 . Which part of the truck is the air compressor connected to?
The door latch
In an air brake system, the air compressor is connected to the engine through gears or a v-belt.
14 . Of the following, which is not a way to prevent drowsiness during a trip?
Avoiding medications that may cause drowsiness
Driving while fatigued can be extremely dangerous. Strategies for preventing drowsiness while driving include getting a full night's sleep before a trip; having someone ride with you so you can take turns driving; scheduling trips for times during which you are normally awake; and avoiding medications that may cause drowsiness.
2026 District Of Columbia | Frequently Asked Questions
To secure a CDL Doubles/Triples endorsement in the District of Columbia, you must first have a valid commercial driver's license (CDL). Then, you must pass the Doubles/Triples Knowledge Test. Once you pass this test, the endorsement will be added to your CDL. Please note that specific training may be required depending on your employer.
To obtain a CDL Doubles/Triples license in the District of Columbia, you need a valid CDL. You must then pass the Doubles/Triples Knowledge Test. Some employers may require specific training. It's also important to have a good driving record, as serious traffic violations could disqualify you from obtaining this endorsement.
While the District of Columbia doesn't specifically require specialized training for a CDL Doubles/Triples endorsement, you must pass the Doubles/Triples Knowledge Test. However, many employers prefer drivers with specific training or experience driving these types of vehicles. It's recommended to seek out training programs to increase your knowledge and skills.
Yes, to obtain a CDL Doubles/Triples endorsement in the District of Columbia, you must pass the Doubles/Triples Knowledge Test at the Department of Motor Vehicles (DMV). This test evaluates your understanding of the special skills and knowledge needed to safely operate these types of vehicles.
The CDL Doubles/Triples endorsement test primarily focuses on knowledge rather than specific maneuvers. You'll need to understand safety procedures, coupling and uncoupling, inspecting doubles and triples, and checking air brake systems. However, actual driving skills for these vehicles are typically evaluated by employers during training or probation periods rather than during the endorsement test.
No, it is not permissible to operate double or triple trailers without a valid CDL Doubles/Triples endorsement in the District of Columbia. Driving these types of vehicles requires specific knowledge and skills, which are validated through the endorsement. Operating without the appropriate endorsement can result in fines, license suspension, or even legal action.
You can add the CDL Doubles/Triples endorsement to your existing CDL. You don't need to initiate a new application for a CDL. However, you must pass the Doubles/Triples knowledge test. After passing the test, the endorsement can be added to your current CDL. Always check with your local DMV for specific procedures and requirements.
Yes, there are certain limitations for drivers holding a CDL Doubles/Triples endorsement. They must only drive the specific types of vehicles for which they're endorsed. They're also required to adhere to safety regulations regarding weight, length, and cargo securement. Additionally, these drivers must comply with all federal and state regulations, including hours of service rules.
In the District of Columbia, a double trailer cannot exceed 61 feet in length and a triple trailer cannot exceed 75 feet. The maximum weight per axle is 20,000 pounds, and the total gross weight, including all trailers and the power unit, cannot exceed 80,000 pounds. Violating these limits can result in fines or penalties.
Yes, there are specific safety guidelines. Drivers must ensure their trailers are correctly coupled and the weight is properly distributed. They should make wider turns, maintain a safe following distance, and check all mirrors frequently. Additionally, drivers must follow all federal and state regulations related to hours of service, vehicle inspections, and hazardous materials if applicable.