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California CDL DMV Knowledge Test Class A 1

Take 6 practice tests for CDL is the best way to prepare for your California DMV exam is by taking our free practice tests. The following question are from real California DMV practice test. More than 95% people pass a DMV exam when practice at DMV Practice Test.

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1. Drivers trapped behind a slow-moving vehicle often:
Follow the vehicle too closely.
Allow the vehicle plenty of space.
Are happy with the speed of travel.

It is common for drivers to tailgate slow-moving vehicles that cannot keep up with the speed of surrounding traffic. If you are being tailgated, allow the other driver to pass your vehicle.

2. Rust around wheel nuts may mean:
It rained recently.
The nuts are loose.
The nuts are too tight.

It is important to inspect your tires before every drive. Rust around wheel nuts may indicate that they are loose.

3. Mirrors should be checked:
Before every lane change.
When changing lanes, but only when other vehicles are nearby.
When changing lanes, but only if it is dark outside.

Always check for traffic in your mirrors before changing lanes. Frequent mirror checks should be a part of your normal scanning routine.

4. To apply for a CDL, an applicant must be at least:
15 years old.
18 years old.
21 years old.

In California, you must be at least 18 years old to apply for a commercial driver license.

5. If you’re unfamiliar with the area in which you must back up, you should:
Get out of your vehicle and walk around the area to become more familiar with it.
Not use both side mirrors because it can be distracting.
Wait for someone else to back up in the area so you can see how they do it.

Before backing up, you should get out of your vehicle and look at your line of travel. Check your clearance to the sides and overhead.

6. A ____ allows a driver to gradually apply spring brakes.
Modulating control valve
Trailer air supply control
Relay valve

A modulating control valve allows a driver to gradually apply spring brakes. In equipped vehicles, the valve is controlled by a lever located on the dashboard.

7. Cargo should have one tie-down for every ____ of cargo.
Five feet
10 feet
20 feet

Cargo should be restrained by at least one tie-down for every 10 feet of cargo. However, all cargo should have at least two tie-downs, no matter the size of the cargo.

8. When stopping a manual transmission vehicle, you should:
Push the clutch in when the engine is close to idle.
Push the clutch out when the engine is close to idle.
Shift into neutral when the engine is close to idle.

When stopping, apply gradual pressure to the brake pedal and stop smoothly. If stopping a manual transmission vehicle, push the clutch in when the engine is close to idle.

9. Poor weight balance:
Improves handling.
Makes handling more difficult.
Increases a driver’s ability to steer.

Poorly balanced loads can lead to unsafe handling. It is important to properly distribute the weight of cargo when loading a vehicle.

10. One way to prevent hydroplaning on wet road surfaces is to:
Ensure that your tires have good tread depth.
Under-inflate your tires.
Drive faster than usual.

When driving on a wet road surface, the risk of hydroplaning is increased if your tire pressure is too low or your tire tread is too worn. If you begin to hydroplane, release the accelerator and push in the clutch to slow down.

11. Which of the following is the best advice for driving in fog?
Try not to drive in fog.
Use your high beam headlights.
Turn off your lights.

Driving in fog is always dangerous and should be avoided entirely if at all possible. If you must drive in fog, be sure to turn on your low beam headlights and fog lights, even during the daytime.

12. What should you do if your vehicle gets stuck on railroad tracks?
Stay in the vehicle.
Get out of the vehicle and call for assistance.
Continue trying to get your vehicle off the tracks until you are successful.

If your CMV gets stuck on railroad tracks, you should immediately leave the vehicle and get away from the tracks. Check the signposts or signal housing at the crossing for emergency contact information and call 911, or another appropriate emergency number.

13. If the low pressure warning signal activates while you are driving, you should:
Continue driving normally.
Exit the road and park as soon as safely possible.
Stop where you are and park.

If the low pressure warning signal activates while you are driving, it is important that you safely exit the roadway as soon as possible and park your vehicle. If the air pressure gets too low, the brakes will no longer work well enough for you to stop safely.

14. If you must drive in reverse, using driver's side backing:
Is always encouraged.
Is discouraged.
Is only recommended if it is raining.

If you must back up, it is safest to back toward the driver's side of the vehicle. This way, as the driver, you will have the best possible view of your path of travel.

15. Regrooved tires are:
Allowed only on the front of a bus.
Allowed only on the rear of a bus.
Not allowed anywhere on a bus.

Regrooved, recapped, or retreaded tires are not permitted to be used on the front of a bus.

16. What do air brakes use to make the brakes work?
Compressed air
Outside air
Non-compressed air

Many large CMVs are equipped with air brakes. An air braking system uses compressed air to operate.

17. As part of the vehicle inspection test, you will be asked to:
Explain what you would inspect and why.
Replace an electrical fuse.
Unload the trailer.

During the vehicle inspection test, you will be required to do a complete inspection of your vehicle. During this inspection, you must explain to the examiner what you are inspecting and why you are inspecting those items.

18. If you are disqualified from driving:
Your employer will be notified by the state.
You must notify your employer within two business days.
You must notify your employer within a month.

You must notify your employer within two business days if your license is suspended, revoked, or canceled, or if you are otherwise disqualified from driving.

19. If there is a fire in your vehicle, you should not:
Park in an area away from buildings, trees, brush, and other vehicles.
Pull into a service station.
Notify emergency services of your problem and your location.

In the event of a vehicle fire, you should leave the road and stop in an open area. Do not pull into a service station as fuels at the service station could catch fire. Report the fire and your location to emergency services.

20. Driving at night is:
Safer than driving during the day.
Just as safe as driving during the day.
More dangerous than driving during the day.

Driving at night is more dangerous than driving during the day because hazards become more difficult to see in the dark.

21. To avoid a hazard, you:
Should always come to a complete stop.
May need to swerve your vehicle out of the way.
Should change lanes without looking.

Stopping is not always the best way to avoid a hazard. If there is not enough space for you to stop to avoid coming into contact with the hazard, swerving out of the way may be your safest option.

22. When driving in fog, you should:
Slow down.
Speed up.
Drive on the shoulder.

It is best not to avoid driving in fog. However, if you must drive under foggy conditions, be sure to decrease your speed.

23. Talking on a cell phone while driving removes about ____ of a person's focus from the task of driving.
10 percent
39 percent
82 percent

Distracted driving is always dangerous. Talking on a cell phone takes away about 39 percent of a person's mental energy that would otherwise be devoted to driving.

24. What must be on all air tanks with air-braked vehicles?
A check valve
A lock
A trap door

All air tanks on air-braked vehicles must have a check valve located between the air compressor and the first reservoir. The valve allows air to flow in only one direction and helps keep air from leaving the air compressor if the compressor develops a leak.

25. When changing lanes, turn signals:
Should not be used.
Should only be used if a vehicle is close to you.
Should be used each time.

Always signal your intentions before turning or changing lanes. Do not assume that other drivers will move out of your way simply because you are signaling to turn.

26. How should you brake if your vehicle's ABS is not working?
Brake normally, as you will still have functioning brakes.
Pump the brake repeatedly.
Press the brake pedal down as hard as you can.

Without a working Anti-Lock Braking System (ABS), your vehicle will still have normal brake function. Continue to drive and brake as you normally would and have your ABS serviced as soon as possible.

27. During an inspection, slack adjusters on S-cam brakes should not move more than:
One foot.
One centimeter.
One inch.

Check each slack adjuster after parking on level ground, setting wheel chocks, and disengaging the parking brake. Pull the slack adjusters to make sure they do not move more than about one inch from where the push rod is attached. If they move more than one inch, they may be out of adjustment and will need to be fixed.

28. When starting your vehicle, the coolant temperature should:
Not change.
Increase gradually.
Quickly jump from low to high.

Watch the gauges in your vehicle before starting a trip. After starting your vehicle's engine, the coolant temperature should begin a gradual rise to the normal operating range.

29. Some air brake systems introduce alcohol into the system to:
Make the brakes work without squeaking.
Prevent ice from forming in the brake system.
Prevent people from breathing the air from the system.

Some air brake systems contain an alcohol evaporator. An evaporator introduces alcohol into the system to help inhibit the formation of ice in cold weather.

30. If you are taking the driving test and the route does not include a railroad crossing, you:
Will not have to do anything related to a crossing.
May have to explain how you would cross railroad tracks.
Will have to take a different route.

During the on-road driving test, if your route does not include a railroad crossing, the examiner may ask you to explain and demonstrate the necessary procedures at a simulated location.

31. Always perform the steps of a pre-trip inspection in the same order each time because:
You will be less likely to forget something.
You will have more time to complete the inspection.
It is required by law.

Completing the steps of a vehicle inspection in the same order before every trip aids in learning what the proper steps are. Additionally, you be less likely to forget a step when going through the checklist in a prescribed order.

32. If a tire fails, you should:
Use the brakes.
Stay off the brakes.

Braking after a tire fails can result in a loss of control. Stay off your brakes, if possible, until your vehicle has slowed considerably.

33. During an applied leakage test, the maximum leakage rate for a double combination vehicle is:
10 psi in a minute.
8 psi in a minute.
6 psi in a minute.
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.

34. During the driving test, the examiner will be scoring you on:
How quickly you arrive to your destination.
Your general driving behavior.

During the on-road driving test, the examiner will be scoring you on specific driving maneuvers, as well as your general driving behavior.

35. If your brakes fail while you are traveling downhill and there is no available escape ramp, you should:
Keep pumping the brakes.
Turn the vehicle off.
Drive into an open field.

If your brakes fail while you are driving downhill, you should first look for an escape ramp to stop your vehicle. If no ramp is available, you should look for an alternative place to bring your vehicle to a stop, such as an open field or side road that flattens out or turns uphill.

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