Commercial Drivers License General Knowledge TestBrought to you by BigCityDriver.com
Passing grade - 10 errors or less.
1. CDL medical certificates must be renewed every:
2. Merging onto a road is safest if you:
inch over into the nearest lane so that other vehicles will give you room.
gain speed on the shoulder and then merge.
wait for a large enough gap in traffic to enter the road.
3. What three things add up to the total stopping distance for your truck or bus?
Attention distance, reaction distance, slowing distance.
Observation distance, response distance, braking distance.
Perception distance, reaction distance, braking distance.
4. You are checking your steering and exhaust systems in a pre-trip inspection. Which of these problems, if found, should be fixed before the vehicle is driven?
Oil on the tie rod.
Black smoke from the exhaust pipe.
Steering wheel play of more than 10 degrees (2 inches on a 20 inch steering wheel).
5. How does weight affect stopping?
Empty trucks can take longer to stop than if loaded, but this is not normally the case for buses.
It doesn't, brakes work the same no matter the weight of the vehicle for both trucks and buses.
Fully loaded trucks take longer to stop, but buses loaded with passengers take less distance.
6. When the roads are slippery, you should:
make turns as carefully as possible.
stop and test the traction while going up hills.
decrease the distance that you look ahead of your vehicle.
7. Which of these is NOT a good rule to follow when caring for injured at an accident scene?
If a qualified person is helping them, stay out of the way unless asked to assist.
Move severely injured persons if there is a danger due to fire or passing traffic.
Keep injured persons cool.
8. You are driving on a straight, level highway at 50 mph. There are no vehicles in front of you. Suddenly a tire blows out on your vehicle. What should you do first?
Stay off the brake until the vehicle has slowed down.
Begin light braking.
Begin emergency braking.
9. After starting the engine, the:
coolant temerature gauge should begin a gradual rise to normal.
oil pressure gauge should take 3-5 minutes to rise to normal.
engine temperature gauge will take 3-5 minutes to rise to normal.
10. You are driving a heavy vehicle with a manual transmission. You have to stop the vehicle on the shoulder while driving on an uphill grade. Which of these is a good rule to follow when putting it back in motion?
Keep the clutch slipping while slowly accelerating.
Let the vehicle roll backwards a few feet before you engage the clutch, but turn the wheel so that the back moves away from the roadway.
Use the parking brake to hold the vehicle until the clutch engages.
11. Which of these statements about speed management is true?
Shady parts of the road allow better traction than open areas.
Road surfaces will freeze before bridges.
When the road is slippery, it will take longer to stop and it will be harder to turn without skidding.
12. Where must you keep shipping papers when transporting hazardous materials?
Under the drivers seat.
In a pouch on the drivers door or on the seat.
In the glove compartment, which must be locked.
13. You should use your mirrors to check:
if your running lights are working properly.
blind spots only.
where the rear of your vehicle is while you make turns.
14. Extra care is needed to keep your vehicle centered in your lane because commercial vehicles:
are often wider than other vehicles.
tend to sway from side to side.
require a lot of room to change lanes.
15. Why is a broken exhaust system dangerous?
Poisonous fumes could enter the cab or sleeper berth.
You could polute the air with exhaust smoke.
Oil on the tie rod may catch on fire.
16. Which of these statements about causes of vehicle fires is true?
Under-inflated tires will NOT cause a vehicle fire.
Carrying a properly charged fire extinguisher will help prevent fires.
Poor trailer ventilation can cause flammable cargo to catch on fire.
17. The purpose of retarders is to:
apply extra braking power to the non-drive axles
help prevent skids.
help slow the vehicle while driving and reduce brake wear.
18. Which of these is especially true about your tires in hot weather?
You should check tire mounting and air pressure before driving.
If a tire is too hot to touch, you should hose it down with water.
A small amount of air should be let out so air pressure remains steady.
19. Which of these is usually true about driving in tunnels?
Headlights are required by law.
There may be strong winds when exiting.
Speeds are limited to 30 mph or less.
20. When driving through work zones, you should:
reduce speed only if workers are close to the roadway.
turn on your parking lights.
watch for sharp pavement dropoffs.
21. When you are passing another vehicle, pedestrian, or bicyclist, you should assume that they:
may move into your traffic lane.
know you want to pass.
see your vehicle.
22. If you are not sure what to use to put out a hazardous material fire, you should:
wait for qualified firefighters.
23. What should you do when your vehicle hydroplanes?
Start stab braking.
Release the accelerator.
24. Which of these is true regarding the use of drugs while driving?
Prescription drugs are allowed if a doctor says the drug will not affect safe driving ability.
No prescription or non prescription drugs are allowed at any time, for any reason.
Use of amphetamines like "speed" is allowed if you are using the drugs to stay awake.
25. Which of these statements about brakes is true?
The heavier the vehicle or the faster it is moving, the more heat the brakes have to absorb to stop it.
Brake drums cool very quickly when the vehicle is moving very fast.
Brake fade is not caused by heat.
26. You are driving a new truck with a manual transmission. What gear will you probably have to use to take a long, steep, downhill grade?
The same gear you would use to climb the hill.
A lower gear than you would use to climb the hill.
A higher gear than you would use to climb the hill.
27. Which of these statements about certain types of cargo is true?
Unstable loads such as hanging meat or livestock can require extra caution on curves.
Oversize loads can be transported without special permits during times when the roads are not busy.
When liquids are transported, the tank should always be loaded totally full.
28. Which of these statements about marking a stopped vehicle is true?
If a hill or curve blocks a drivers vision within 500 feet, move the rear reflective triangle back beyond the hill or curve.
The vehicles taillights should be kept on to warn other drivers.
You must put out your emergency warning devices within 5 minutes.
29. Which of these is true about rear drive wheel braking skids?
Locked wheels usually have more traction than rolling wheels.
Front wheels slide sideways to try to "catch up" to rear wheels.
On vehicles with trailers, the trailer can push the towing vehicle sideways.
30. Which of these statements about double clutching and shifting is true?
Double clutching should not be used when the road is slippery.
Double clutching should only be used with a heavy load.
You can use the tachometer to tell you when to shift.
31. Which of these is true about your overhead clearance?
Paving a road does not affect the clearance height under bridges or overpasses.
The weight of a cargo can change the height of your vehicle.
Warnings are always posted for low clearance areas like bridges and overpasses.
32. How far should a driver look ahead of the vehicle while driving?
33. If you need to leave the road in a traffic emergency, you should:
try to get all the wheels off the pavement.
avoid braking until your speed has dropped to about 20 mph.
avoid the shoulder because most shoulders will not support a large vehicle.
34. Which of these statements about backing a heavy vehicle is NOT true?
You should back and turn toward the drivers side whenever possible.
You should use a helper and comunicate with hand signals.
Because you can't see, you should back slowly until you slightly bump into the dock.
35. Which of these lights cannot be checked at the same time?
Headlights, brake lights and clearance lights.
Turn signals, taillights and clearance lights.
Turn signals, brake lights, and four-way flashers.
36. Which of these is correct about emergency or evasive action?
Stopping is always the safest thing to do in an emergency.
In order to turn quickly, you must have a firm grip on the steering wheel.
You can usually stop more quickly than you can turn to miss an obstacle.
37. You are driving a vehicle that could safely be driven at 55 mph on an open road. But traffic is now heavy, moving at 35 mph, in a 55 mph zone. The safest speed for your vehicle is most likely:
38. According to the Commercial Driver Supplement, why should you limit the use of your horn?
It can startle other drivers.
On vehicles with air brakes, it can use air pressure that may be needed to stop.
You should keep both hands tightly gripping the steering wheel at all times.
39. Which of these is true about bad weather and driving conditions?
When the temperature drops, bridges will freeze before roads.
The road is more slippery as rain continues than when rain begins.
Driving conditions become more dangerous as the temperature rises above freezing.
40. To determine blood alcohol concentration (BAC) for a person, it is neccessary to know:
how often the person drinks alcohol (tolerance level).
how much the person weighs.
how old the person is.
41. Which of these happens when a tire blows out at highway speed?
A vibrating feeling.
A hissing sound.
A rapid drop in speed to less than 20 mph.
42. You are driving a 40 foot vehicle at 35 mph. The road is dry and visibility is good. What is the least amount of space that you should keep in front of your vehicle to be safe?
43. Truck escape ramps:
cannot be used by certain types of heavy vehicles.
are not for buses.
help avoid damage to vehicles.
44. Your brakes can get wet when you drive through a heavy rain. What can this cause when the brakes are applied?
Excessive brake wear.
45. If you are being tailgated, you should:
flash your brake lights.
signal the tailgater when it is safe to pass you.
increase your following distance.
46. When driving in cold weather, your tire tread should:
be checked every 100 miles or every 2 hours.
be double the depth required in normal weather.
provide enough traction to steer and push the vehicle through snow.
47. Which of these statements about staying alert to drive is true?
A half-hour break for coffee will do more to keep you alert than a half-hour nap.
If you must stop, pull over on the side of the road for a short nap.
Sleep is the only thing that can overcome fatigue.
48. You are checking your brakes and suspension system for a pre-trip inspection. Which of these statements is true?
Just one missing leaf spring is not dangerous.
Spring hangers that are cracked but still tight are not dangerous.
Brake shoes should not have oil, grease or brake fluid on them.
49. For a first offense of driving a commercial vehicle under the influence of alcohol or drugs, you will lose your CDL for at least:
50. A full stop is required at a railroad grade crossing when:
the crossing is located in a city or town with frequent train traffic.
there are no flagmen, warning signals, or gates at the crossing.
the nature of the cargo makes a stop mandatory under state or federal regulations.
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