Knowledge Test Class B #1
Class B Driving Test | District Of Columbia 2025 #1 Page 5 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 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 CDL class B requirements may vary from state to state.
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29 . Hydroplaning occurs when:
Front tires have less traction than rear tires.
Hydroplaning is an effect that occurs on wet roads when tires lose traction with the road surface and begin gliding along on a layer of water.
30 . If asked to sight-side back your vehicle into an alley, you should first:
Pull past the alley and stop parallel to the outer boundary.
If you are asked to alley dock, you should first pull past the alley and stop your vehicle in a position that is parallel to the outer boundary. From there, you should back your vehicle entirely into the alley parking area. Your vehicle should be parked in a straight position within the boundaries of the parking space.
31 . When approaching a curve during the on-road driving test, you must do all of the following, except:
Steadily use the brakes throughout the curve.
When approaching a curve during the on-road driving test, you should thoroughly check traffic in all directions. Before entering the curve, reduce your speed sufficiently so that further braking or shifting is not required. Keep your vehicle in its lane and continue checking traffic in all directions.
32 . Air tank drains:
Must remain open during driving.
Compressed air in an air brake system usually contains a certain amount of water and compressor oil. The water and oil can damage the brakes if left to accumulate in the system. Manually operated air tank drains must be opened daily to remove this build-up.
33 . Trailers should:
Be loaded with all the weight directly behind the cab.
Overloading a vehicle is dangerous. It can damage the vehicle and interfere with the driver's ability to control it.
34 . Most drivers are the least alert:
After work.
Fatigue and lack of alertness are major hazards when driving at night. Most people are the least alert at night, especially after midnight.
35 . When checking the exhaust system, it should be:
Cracked.
