District of Columbia
CDL Practice Test

Simply because the District of Columbia is the only place in the country that has legal taxation without representation doesn't mean there are no laws at all! Every commercial driver in Washington DC must have a valid commercial driver's license. Typically those licenses will be issued in other jurisdictions but Washington DC can and does issue its own. This online exam will help you practice for the District of Columbia CDL Test. You will be presented with 40 questions and you must answer 34 questions correctly to pass. There is a 50 minute time limit. You may not go back once you answer a question. Click the "Start Test" button below to begin. Good luck!

1 / 40

Which trailer is most likely to tip over due to the crack the whip effect?

the last trailer of a double

the first trailer of a triples

the last trailer of a triple

the heaviest trailer

2 / 40

Select the true statement in regards to handing triples and doubles

due to the crack the whip effect, the rear trailer of a 100 foot triple is less likely to tip than a single trailer

due to off tracking, a triple bottom rig can come to a stop quicker than a 5 axle semi trailer

a sudden movement of the steering wheel may result in the rear trailer tipping over

none of the answers listed

3 / 40

Select the factors that can cause your brakes to fade or fail:

all of these answers are correct

using the service brakes excessively

not relying on engine braking enough

the brakes are out of adjustment

4 / 40

Select the item that is not checked in the engine compartment:

The coolant level

The oil pressure

The power steering fluid

The level of the oil

5 / 40

Which of the following statements is FALSE?

anti-lock braking systems (ABS) only activate when wheels are about to lock

if a tire blows, you should put the brakes on hard to stop quickly

you can almost always turn to miss an obstacle more quickly than you can stop

stopping is not always the safest thing to do in an emergency

6 / 40

The best way to describe a dual air brake system is:

all of these answers are correct

there is a primary and secondary system that is 2 separate air brake systems

there are 2 separate air brake systems that supply air to the trailer if there is one

there are 2 separate air brake systems that have their own hoses, lines etc

7 / 40

When there is a hazardous materials emergency. You should:

Keep people away and warn them of the danger.

Prevent smoking and keep open flames away.

All of these answers are correct.

Contact emergency authorities.

8 / 40

Do empty trucks have the best braking?

yes, but only if the truck is newer than 1998

yes, but only on wet surfaces

yes

9 / 40

Of the following hazardous material classes, which is the most dangerous?

Division 62

Division 61

Division 63

Division 64

10 / 40

What is a king pin?

it is a pin that locks the trailer to the tractor on the fifth wheel

it is a pin that a driver receives for being a safe driver

it is a pin that holds the wheel on to the axles

it is a pin that locks the air brake lines together

11 / 40

You should check your tires every ____ or every ____ when driving in very hot weather.

1 hour, 50 miles

3 hours, 200 miles

2 hours, 100 miles

5 hours, 250 miles

12 / 40

If your engine runs a pump used during delivery of compressed gas, should you turn off the engine before or after unhooking hoses after delivery?

Turn it off before product transfer, before you hook the hose.

Turn it off after product transfer, before you unhook the hose.

Turn it off during product transfer, while unhooking the hose.

None of these answers are correct.

13 / 40

What keeps air in the tanks should the air compressor develop a leak?

the one-way check vavle

the tractor relay valve

the engine protection valve

the air compressor

14 / 40

What will happen right away should the service air line come apart but the emergency line is intact while driving a combination vehicle?

the trailer's air tank will leak through the one line

the emergency tractor brakes will activate

you will come to a complete stop

nothing will occur until you try to use the brakes

15 / 40

When backing, what is the best method to use to avoid blind spots?

look at your path

use mirrors on both sides

back towards the driver's side, where you can see better

use a helper

16 / 40

What does it mean when the safety valve releases air?

you need it to have it checked out by a mechanic because something is wrong

pressure has passed 150 psi

all of these answers are correct

there is too much air in the air compressor

17 / 40

The best way to test if the spring brakes come on automatically is to:

apply pressure on and off the brake pedal until the parkng brake valve pops out on tractor-trailer vehicles

all of these answers are correct

apply pressure on and off the brake pedal until the manufacturer's low psi specification has been met for the spring brakes to deploy

apply pressure on and off the brake pedal until the parking valve pops out on single vehicles

18 / 40

What is the first thing to do if your vehicle catches fire while driving?

pull off the road and park in an open area

open the hood and let the flames die down

open the door and jump out of the vehicle

find a service station to pull into

19 / 40

Select the step that comes first:

lower the landing gear

shift into reverse

apply a firm pressure to the trailer brakes

connect the air supply lines

20 / 40

When not towing a trailer, why should the tractor glad hands be locked?

the connected brake circuit will become a back up air tank

the system pressure will not build up

it keeps water and dirt out of the lines

this should never be done

21 / 40

This item should be firmly attached the to frame, be solid, and clear of objects:

The lock pins

The locking jaw

None of these answers are correct answers are correct

The catwalk

22 / 40

A truck with baffles will handle:

None of the answers listed.

Heavier that it actually is.

With less front to back surge compared to trailers without baffles.

The same as a tanker with no baffles.

23 / 40

Select the true statement about emergency steering and tankers:

None of the answers listed.

Do not apply the brakes when making quick movements of the steering wheel.

Have a firm grip on the steering wheel before making quick movements of the steering wheel.

It is easier to counter steer than other vehicles.

24 / 40

You should____in order to inspect the coupling.

if necessary, use a flashlight

make sure the locking lever is in the open position

make sure to have space between the lower and upper fifth wheel

have the fifth wheel jaws open

25 / 40

How do you check the air compressor governor "cut in" and "cut out" pressures?

monitor the air pressure gauge

all of these answers are correct

run the engine at a fast idle

decrease the tank pressure by stepping on and off the brake

26 / 40

Make sure that____when the front trailer supports are up and the trailer is resting on the tractor.

there is enough clearance between the lower and upper fifth wheel

the safety latch is in the open position

the kingpin has been removed

there is enough clearance between the landing gear and the tractor frame

27 / 40

To test the tractor-trailer connection for security, you should:

drive forward in a high gear with the trailer brakes on and check it

drive forward in a low gear with the trailer brakes locked and then look at it carefully

rock the trailer side to side with the trailer brakes on

drive forward with a sharp jerk

28 / 40

You do not have a hazardous materials endorsement on your commercial driver license. When can you legally haul hazardous materials?

Only in the event of a federally declared emergency situation.

Never.

Only when the vehicle does not require placards.

Only when the shipment does not cross state lines.

29 / 40

Suspension systems:

keep the brake drums from failing

keep the axles in place

keep the steering wheel tight

keep the load secure

30 / 40

To transport cargo safely, which of these are you NOT responsible for?

ensuring the freshness of sealed cargo

recognizing possible overloads

making sure that cargo is properly secured

inspecting the cargo

31 / 40

To inspect the______you should pump the pedal 3 times and hold it down for 5 seconds while making sure the pedal doesn't move during those 5 seconds.

engine brakes

parking brakes

air brakes

hydraulic brakes

32 / 40

By law, the warning lights must only be used when approaching a:

Busy intersection.

Any stop the bus makes.

Stop to load or unload students.

Sharp turns.

33 / 40

When driving tank vehicles you should:

Come to a stop before entering a curve and then accelerate through it.

None of the answers listed.

Maintain the posted speed limit as you enter the curve.

Decrease your speed before entering a curve and then accelerate through it.

34 / 40

This item does not need to be checked during the cab check.

The horn

The defroster/heater

The air conditioning

The windshield wipers and fluid levels

35 / 40

If you have to swerve to avoid a hazard, it's important to:

None of these answers are correct.

Warn passengers with a loud and clear voice.

Know where other vehicles are around your bus by checking your mirrors.

Make sure your passengers are wearing seat belts.

36 / 40

Vehicle handling can become unsafe if the weight is not properly balanced. Hard steering can be caused by:

too much weight on the steering axles

too little weight on the driving axles

high center of gravity

under loaded front axles

37 / 40

The minimum tire tread depth for front tires is:

1/32-inch

3/8-inch

4/32-inch

1/2-inch

38 / 40

Select the true statement in regards to if a glad hand on the blue air line is missing a seal.

you should remove one from the red air line to use as a temporary replacement

it is not a big problem

there may be a service line air leak

there may be an emergency line air leak

39 / 40

The longest crack that brake or disc drums can have is:

None of the answers listed.

1/2 the width of the friction area.

1/2 inch across in a straight line.

Cracks are not permitted.

40 / 40

The two main things to look ahead for while driving are _____.

fire and flooding

traffic and road conditions

truck stops and police

bridges and tunnels

Your score is

The average score is 0%

5/5 - (1 vote)

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How To Get A District of Columbia Commercial Drivers License

In the District of Columbia, there are classifications of motor vehicles that may only be driven by those with a current commercial drivers license. Additionally, there are four classes of endorsements, including school bus, passenger and tanker. Any vehicle with a gross weight rating over 26,000 pounds is considered commercial in the District of Columbia.

Additional endorsements also include:

Hazardous Materials
Double/Triple Trailer
Tanker
Passenger
School Bus

Requirements to Obtain a District of Columbia CDL:

Have a valid non-commercial driver license
Meet identity, residency, and good driving history eligibility qualifications
Take the applicable CDL knowledge tests
Get a CDL learner permit
Pass the CDL road skills test

A Commercial Driver in Washington DC is held to a higher standard than drivers of typical passenger or other non-commerical vehicles. CDL holders must pass both written tests as well as a practical / skills test. You may practice for the written test using our online CDL test tool above. Upon successful completion, of the official Washington DC CDL skills test, you will be a fully licensed driver and ready to take to the open road!

Hit the Open Road

District of Columbia CDL License Test Tips

You think you're ready? Hold on there, Turbo! Check out these CDL Test Tips before you go zipping to the DMV for your exam!

You must have your CDL learner permit for at least 30 days prior to scheduling your road skills test.
Make an appointment on the DC Online Road Test Appointment Scheduler. Make sure to have your driver license number handy...you'll need it.
On your test day, arrive 15 minutes early. You will need to bring a CDL licensed driver aged 21 or older and this person must hold the CDL class and endorsements you are testing for.

You'll need to bring a few other things with you as well.

valid CDL learner permit
valid NCDL
DOT medical certification card
an appropriate vehicle in which to complete your CDL test
current registration and insurance for the vehicle

If you fail the CDL test you must wait three calendar days before attempting it again. If you fail a second time, you cannot re-test for ninety days!

Additional Information

Information on the Washington DC Department of Motor Vehicles

The District of Columbia CDL certifying agency is responsible for testing and certifying all commercial drivers. To get more information contact them via:

Website: https://dmv.dc.gov/service/obtain-commercial-driver-license
Phone: 202.673.6813
Email: [email protected]

Additional Washington DC CDL Helpful Links

Please use the links below to learn more about helpful topics related to the District of Columbia CDL testing program or other CDL-related topics.

District of Columbia CDL Practice Test

District of Columbia Drivers Test

District of Columbia Motorcycle Test

District of Columbia CDL Test

CDL Category Practice Tests

CDL Practice Test

How To Get A District of Columbia Commercial Drivers License

Hit the Open Road

District of Columbia CDL License Test Tips

Additional Information

Information on the Washington DC Department of Motor Vehicles

Additional Washington DC CDL Helpful Links

District of Columbia
CDL Practice Test