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General Knowledge CDL Practice Test Part B

CDL Test Practice Exams & CDL Training Materials

Taking the CDL test will be much easier after going through our practice CDL tests here online. This is the General Knowledge portion of the CDL written practice exam. These questions are very similar to the ones you'll find on the actual CDL written test you'll be taking to get your CDL license. Follow along with the test questions below and read through the explanations that follow each CDL test question to get some better insights into the CDL exam and the trucking industry itself.

1. What are two main things to look for ahead?

A. Road Signs
B. Police
C. Rest Area
D. Traffic and road conditions


Answer

D. Traffic and road conditions

It takes a long time to slow down a tractor trailer and only an instant for things in front of you to go horribly wrong. Always scan the road ahead and always know what's beside you and behind you. You can't take evasive action to avoid an accident if you don't know if someone is beside you or behind you. Always plan your escape route in case something goes wrong in front of you and keep plenty of following distance.

2. What is your most important way to see the sides and rear?

A. By looking out the window
B. Checking your mirrors regularly
C. Getting on the C. B. radio.


Answer

B. Checking your mirrors regularly

Mirrors used to be the only way to see what was beside you or behind you but now you have all sorts of video and radar-based equipment to try to help you know if something is in your blind spot. But without a doubt, at this point, your mirrors are still the best way to know what's around you.

3. What does "communicating" mean in safe driving?

A. Letting other drivers know you're there to help prevent accidents.
B. Using hand signals.
C. Driving a brightly colored vehicle.


Answer

A. Letting other drivers know you're there to help prevent accidents.

If you think about it, what causes multi-vehicle accidents? Simple - one vehicle not knowing what another vehicle was going to do. Even if someone runs a stop sign, goes the wrong way on a one way street, or stops in the middle of the interstate for no reason - if everybody knew that person was going to do that, it would be easy to avoid an accident. Keep that tractor trailer under control and try not to do anything unpredictable. Use your signals, change lanes slowly, etc. Let other people around you know what you are going to do before you do it - it's one of the most important factors in road safety.

4. Where should your reflectors be placed when stopped on an undivided highway?

A. Within 10 feet of the front or rear and 100 feet behind and ahead of the vehicle.
B. Within 50, 100, and 150 feet of the vehicle.
C. Within 10, 20, and 30 feet of the vehicle.


Answer

A. Within 10 feet of the front or rear and 100 feet behind and ahead of the vehicle.

Make sure you have those triangles in the truck before leaving your company's terminal. The DOT loves to check for those during an inspection and make sure you use them if you break down on the side of the road.

5. What three things add up to total stopping distance?

A. Road conditions, reaction distance, and braking distance
B. Perception distance, reaction distance, and braking distance
C. Braking distance, controlling speed, and reaction distance.


Answer

B. Perception distance, reaction distance, and braking distance

The earlier you can detect a problem, the more following distance you have, and the slower you're going, the sooner you'll be able to react to something in front of you and the better your chance of avoiding an accident. Also make sure you know what vehicles are around you and that you have an escape route in mind at all times.

6. If you go twice as fast, will your stopping distance increase by:

A. twice
B. three times
C. four times
D. five times


Answer

C. four times

Speed greatly increases your stopping distance - simple as that. But remember, it's critically important to calculate your safe stopping distance based on a number of factors, including speed and road conditions. Following distance is critically important to preventing accidents.

7. Empty trucks have the best braking.

A. True
B. False


Answer

B. False

This question is too general. If you see it on the CDL test, the correct answer is no. However, the real-life correct answer is "it depends". On dry ground, an empty truck can stop faster than a loaded truck. On real slick roads, sometimes a heavy truck will grip better and stop a bit sooner. The key thing for maintaining control is to prevent locking up the wheels. Tractor trailer brakes are made to handle 80,000 pounds safely. So when that trailer is empty, you have far more braking force than you need. If you can control it, you'll be ok. You just don't want to lock up the wheels and lose directional control of the truck.

8. What is hydroplaning?

A. driving in the snow
B. when the tires lose their contact with the road
C. when you hit a pot hole


Answer

B. when the tires lose their contact with the road

The answer should say "when your tires lose contact with the road after hitting standing water". But anyhow, hydroplaning is when the tires basically slide along the surface of standing water. Locking up the tires on a wet road is not necessarily hydroplaning. The tires may still be in contact with the road, but there is not enough friction to keep them turning. But if you go quickly through standing water, the tires can skim along the surface of the water instead of cutting through the water down to the road surface. You have no directional or braking control of a tractor trailer that is hydroplaning.

9. What is black ice?

A. Dirty snow
B. Rain and snow mixed
C. A thin layer of ice clear enough that you can see the road underneath it.


Answer

C. A thin layer of ice clear enough that you can see the road underneath it

Black ice is scary is what it is! Black ice looks exactly like a wet road. The two best ways I know of to attempt to determine if the road is wet, or if it's ice, is to look at your mirror brackets to see if they are iced up. If so, it's quite likely the road is, too. The other way is to look for water spray to be coming off the tires of other vehicles. If you don't see any water spray, then it's likely the road surface is icy.

10. If the vehicle ahead of you is smaller than yours, it can probably:

A. out-run you.
B. stop faster than you can.
C. take turns faster than you can.


Answer

B. stop faster than you can.

Well, I guess all of those are technically true, but I've warned you before that you have to watch out for the wording on these CDL tests. They can be quite tricky. They want you to pick the 'best' answer. And it's pretty safe to assume that all vehicles on the road will be able to stop faster than your tractor trailer. There is no safety advantage in assuming you can stop faster than anyone else can.

11. If you are driving a 30 foot vehicle at 55 mph, how many seconds of following distance should you allow?

A. Four seconds
B. Eight seconds
C. Six seconds


Answer

A. Four seconds

Again, this is not a very good question. What if your 30 foot vehicle weight one hundred million pounds? But that's how these CDL tests are put together. They're tricky. Know the calculations for stopping distance. Anytime the CDL manual gives you specific numbers you can expect they will likely come up on the CDL test.

12. You should decrease your following distance if somebody is following you too closely.

A. True
B. False


Answer

B. False

Never try to run faster to get somebody off of your tail. They'll likely just speed up and stay with you. If there is a passing lane that they can use to get around you, sometimes you can actually slow down a little bit and they will pass you instead of following at such a slow speed. You do not want to decrease the following distance you are keeping ahead of your tractor trailer, though.

13. If you swing wide to the left before turning right another driver may try to pass you on the right.

A. True
B. False


Answer

A. True

This causes a lot of accidents with tractor trailers. You want to keep your trailer tandems as far to the right as possible while still being able to make it around the turn safely. You must be very careful to make sure nobody comes up along your right side when you're making a right-hand turn.

14. You should use low beams whenever you can.

A. True
B. False


Answer

B. False

Yet again, another tricky CDL test question. There are times when using your high beams is safer than using your low beams. Notice the question says "whenever you can". Well, you always can - but that doesn't mean it's always the safest thing to do.

15. What should you do before you drive if you are drowsy?

A. Drink some coffee.
B. Take some caffeine pills.
C. Get some sleep before you drive.
D. None of the above.


Answer

C. Get some sleep before you drive.

Getting some sleep is the only real cure for sleepiness. Caffeine may give you a short-term boost, but be aware that you're likely going to crash that must faster and harder once it wears off. Sleep is the only real cure for sleepiness. You must be aware of this and be very careful.

CDL Practice Tests

More CDL Training Resources From TruckingTruth

High Road Practice Questions

We've taken the questions from the High Road Training Program and put them in their own section of the site. The quizzes also contain quotes from the CDL manual and advice from TruckingTruth.

CDL Practice Test Android App

We've also converted the quizzes from the High Road Training Program into an Android app. Now you can practice taking the quizzes when you're on the go! The quizzes also contain quotes from the CDL manual and advice from TruckingTruth.

Tips On Passing The CDL Exam

Passing your CDL exam involves taking written exams, oral exams, and of course driving and backing tests. We have a series of articles that will help you understand what you're being tested for and how to give yourself the best chance of passing.

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