Knowledge Test Class B #1
Class B Driving Test | District Of Columbia 2026 #1 Page 3 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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15 . If a vehicle has air brakes, the air compressor drive belt should be checked before each drive. In what condition should the belt be?
Bumpy
When inspecting a vehicle with air brakes that has a belt-driven air compressor, you should check the condition and tightness of the belt. It should be in good condition.
16 . A dual air brake system:
Has two separate air brake systems, but uses a single set of controls.
A dual air brake system has two separate air brake systems that use a single set of brake controls. One system typically operates the regular brakes on the rear axle or axles. The other system operates the regular brakes on the front axle.
17 . Brakes can get out of adjustment:
If brakes on one side are used more often than brakes on the other side.
Brakes are particularly prone to getting out out adjustment if they are hot. Use proper braking techniques to avoid letting your brakes overheat.
18 . Passive railroad crossings:
Should never be crossed by a CMV.
Railroad crossings that are not controlled by any type of traffic control device are known as passive crossings. The decision to proceed across tracks at a passive crossing is entirely up to the driver.
19 . Suspension system defects may include all of the following, except:
Cracked lights.
Defects to check for when inspecting your vehicle's suspension system include cracked or broken spring hangers; missing or broken leaves in a leaf spring; and leaking shock absorbers. If you spot any of these issues, be sure to have them repaired.
20 . If a load is 10 feet long, it should be secured by at least ____ tie-down(s).
Four
On flatbed trailers and trailers without sides, cargo needs to be tied down. There should be at least one tie-down for every 10 feet of cargo. Regardless of the size of the cargo, at least two tie-downs must be used.
21 . Regarding winter driving, all of the following are true, except:
Use a gauge to verify that each tire has a safe tread depth.
When driving during the winter, it is particularly important that your tires have adequate tread. You need a tread depth of at least 4/32 of an inch in every major groove on the front tires, and at least 2/32 of an inch on the back tires. Check the tread depths by using a gauge.
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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.
