Knowledge Test Class B #2
Class B Driving Test | District Of Columbia 2024 #2 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 2024, 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 . When an engine is started:
The hood must be open.
After a vehicle is started, the warning lights and buzzers should go out after a few seconds. If the warning signals do not turn off, there may be something wrong with the vehicle.
16 . Air tank drains:
Must remain open during transit.
In an air brake system, the air storage tanks must be drained to remove accumulated water and compressor oil. Failing to do so can cause damage. Manually operated drains should be used at the end of each day of driving.
17 . Federal and state laws require:
Drivers to inspect their vehicles, but only if they will be transporting hazardous materials.
Commercial drivers are required by federal and state laws to inspect their vehicles before every trip. Regular inspections can help drivers identify issues before they become dangerous and costly.
18 . 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.
19 . During an applied leakage test, the maximum leakage rate for a double combination vehicle is:
4 psi in a minute.
It is important to know the maximum air loss rate that is safe for your specific vehicle. A double combination vehicle should have a leakage rate no higher than 4 psi in a minute during an applied leakage test.
20 . What is black ice?
Ice that is easily seen
Black ice is a thin layer of ice that is clear enough for the road surface to be seen through it. A road covered in black ice may look like it is merely wet.
21 . When a tire goes flat, you may hear a loud bang. The truck will be affected:
Only if the truck is hauling a load.
