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

Select the statement that describes smooth bore tanks:

They are divided with holes from liquid to flow through controlling surge.

None of the answers listed.

They are divided down into smaller tanks.

They are 1 large tank.

2 / 40

What is NOT one of the four skill areas that operating a commercial vehicle requires?

safely backing

steering

accelerating

first aid certification

3 / 40

In what position should the shut off valves on a the rear of the front trailer be in on a set of double trailers?

in a 1/3 way open position

in a closed position

in an open position

in a halfway open position

4 / 40

This object should not be spliced, cut, chafed, or worn through to allow steel braid to show.

Mud flaps

Tires

Electric/air lines

The lockjaw

5 / 40

Tires should should be replaced:

when the tread separates

when there are broken valve stems

all of these answers are correct

if the tread depth on your front tires is less than 4/32 deep

6 / 40

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

Division 61

Division 64

Division 63

Division 62

7 / 40

On tandem axle for trailers, the sliding mechanism and locking device is:

Tandem release (locking pin/arm)

Metal frame

Air brake system

Fifth wheel

8 / 40

Double and triple trailers should be driven with care to avoid a rollover or jacknife.

true

only in ideal conditions

false

only on downgrades

9 / 40

What should you check for when inspecting a converter dolly?

that the converter dolly air tank drain valve is in the closed position

all answers listed

that the spare tire is secured if there is one

that the safety chains are secured to the trailer

10 / 40

Select the true statement in regards to large combination vehicles taking longer to stop.

they take the same amount of time to stop when empty or loaded

they take longer to stop when loaded down

they take longer to stop than bobtail tractors

they take longer to stop when they are empty

11 / 40

Why does it take special skills to haul a tank vehicle?

There is a high center of gravity.

It is top heavy.

All of the answers listed.

The weight of the load is high up off the road.

12 / 40

This should have no illegal stickers, dirt, obstructions, or damage to the glass.

The headlights

The rearview mirror

Mirrors and windshield

None of the answers listed

13 / 40

Select the true statement about baffled tankers:

None of the answers listed.

It has walls with holes inside for liquid to flow through.

It has hollow balls in it to slow the motion of the liquid in the trailer.

It has separate tanks.

14 / 40

Rods, connecting links, and arms from the steering box to the wheel are a part of the:

Steering linkage

Braking system

CB radio

Power steering fluid

15 / 40

Select the true statement in regards to the center of gravity for tanks:

The center of gravity is generally lower than with other large trucks.

The vehicle can handle higher speeds around curves than other large trucks.

None of the answers listed.

The vehicle can turn over even when driving at the posted speed limit for curves.

16 / 40

Select the true statement in regards to when a bulk tank vehicle stops at an intersection on a slippery surface:

The trailer may slide to the side due to the rocking motion.

The trailer may slide into the oncoming traffic.

The liquid may leak out of the tank.

The movement of the liquid may push the truck into the intersection.

17 / 40

Which of the following statements about overhead space is true?

an empty van is lower than a loaded one

warning lights are always installed on low bridges and overpasses

athe heights posted at bridges are usually accurate

the weight of the cargo changes a truck's height

18 / 40

Select the true statement in regards to quick steering movements and double trailers:

nothing will occur

it is easier to tip doubles and triples from quick steering movements than other vehicles

you should apply a firm pressure to the brake pedal at the same moment you do quick steering movements

it is easier to countersteer doubles/triples than other vehicles

19 / 40

What is most likely to occur when driving a set of doubles and a set of trailer wheels goes into a skid?

nothing will occur

no matter how you turn the steering wheel, the rig will continue in a straight line

the rig will slide sideways but stay in a straight line

there will be a trailer jackknife

20 / 40

How do you check the coolant level?

Inspect the reservoir sight glass or remove the radiator cap if the engine isn't hot.

Remove the radiator cap once it is at operating temperature.

None of the answers listed.

While wearing rubber gloves and safety glasses.

21 / 40

What is a supply pressure gauge used for?

it tells you how much pressure is in the air lines

it tells you how much pressure is in the air tanks

all of these answers are correct

it tells you how much slack is in the slack adjusters

22 / 40

A trailer is at the right height to have the tractor backed up to it when:

it'll raise slightly when the tractor is backed up under it

the top of the kingpin is even with the bottom of the fifth wheel

the kingpin is about 1 1/5 inches above the fifth wheel

the fifth wheel will not come in contact with the kingpin

23 / 40

The brake pushrod should not move more than____for manual slack adjusters.

movement is not allowed

an inch when pulled by hand with the brakes released

1-2 inches while the brakes are set

checking is not required in vehicles built after 1994 as they have automatic slack adjusters

24 / 40

How often should you drain your air tanks?

at the end of each shift

at the beginning of each month

at the end of each trip

at the end of each week

25 / 40

With the controlled braking method, you _____?

apply the brakes all the way until the wheels lock up, release the brakes and apply them again when the wheels start to roll again

repeatedly tap the brakes as fast as you can

apply the brakes as hard as you can without locking the wheels

lightly apply braking pressure

26 / 40

It takes special care to drive tankers with liquid in them because:

The low center of gravity of the load.

The high center of gravity of the load.

The movement of the liquid even when the truck is stopped.

The baffles create odd rocking motions.

27 / 40

Air pressure loss in a vehicle with a fully charged air system should be less than_______after the initial drop and brake applied.

none of the answers listed

4 psi a minute

1 psi a minute

3 psi a minute

28 / 40

You must carry a gas mask with you when transporting:

Chlorine

Poison

Liquid gas

Flammable materials

29 / 40

While completing the 1st component of the air brake check you are required to fully push down on the foot brake and _____.

see if the air pressure drops more than 3 lbs in a minute while holding it down for that full minute in a single vehicle

both of the answers listed

none of the answers listed

see if the air pressure drops more than 4 lbs in a minute while holding it down for a full minute in a combination vehicle

30 / 40

Which of the following should you do when driving the school bus in high wind?

Pull off the road to wait for the winds to die down.

Keep a strong grip on the steering wheel and try to anticipate gust.

Drive only head-in to the wind to avoid cross-wind buffeting.

Speed up to get away from the wind as quickly as possible.

31 / 40

The bus driver must accept responsibility for supervising and controlling students while on the bus route. Who is the person in charge?

The school district superintendent.

Students on the bus.

Bus driver.

Parents of the students on the bus.

32 / 40

Which of the following is NOT an appropriate reason to flash your braking lights?

to signal to tailgaters that they are too close to your vehicle

to alert drivers behind you that there are hazards ahead

to warn drivers behind you when you need to slow down

to warn vehicles approaching you from behind that you are driving slowly

33 / 40

Which of the following parts do not get checked in the Bus Interior inspection:

Seat coverings.

Emergency exit handles.

Each hand-hold and railing.

Signaling devices, including the restroom emergency buzzer, if the bus has a restroom.

34 / 40

You need to be extra careful when driving smooth bore tanks:

When unloading or loading.

When hauling food or milk products.

All answers listed.

When stopping or starting.

35 / 40

Two causes of tire fires are ______.

under-inflated tires and poor retreads

duals that touch and road debris

hot brakes and under-inflated tires

under-inflated tires and duals that touch

36 / 40

It is important to know the outage required for the liquids you carry because:

None of these answers are correct.

Some of the denser liquids don't need any.

Tank baffles may not always be permitted with outage.

Some liquids will expand more than others when warm.

37 / 40

Drivers placard their vehicle to _____ the risk.

take away

minimize

communicate

elevate

38 / 40

You should___when driving down a long steep hill.

use the engine brakes only

begin braking once the vehicle is 10 mph above safe speed

repeatedly pump the brake pedal

release the brake once the vehicle is traveling 5 mph below the safe speed

39 / 40

One reason hauling liquids in tank vehciles require special care is:

Because of strong winds.

Because of uneven expansion.

Because of the extreme weight.

Because of the movement of the liquid.

40 / 40

This object should be checked to make sure that the cap(s) are on tight, that it is secure, and there are no leaks.

Exhaust system

Windshield fluid line

Fuel tank

Air coolant system

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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