CDL Double-Triple
Trailers Test

This is the Commercial Vehicle Driver's License Test covering Double and Triple Trailers. You will be presented with 40 questions and you must answer 34 questions correctly to pass. There is no time limit. You may not go back once you answer a question. Click the "Start Quiz" button below to begin. Good luck!

1 / 40

The pintle hook should be_____ and the converter dolly air tank drain valve is___when doing a walk around inspection of a triple or double trailer.

free, open

free, closed

latched, closed

latched, open

2 / 40

Which trailer should be the first one after the tractor?

the trailer that is the shortest in length

the trailer that weighs the most

none of the answers listed

the trailer that weighs the least

3 / 40

Your rig should be parked on__to uncouple double trailers.

the company's lot

level ground

grass

a downgrade

4 / 40

Start by___when coupling.

coupling the converter hook to the pintle tongue of the first trailer

backing the converter dolly under the second trailer

having the second trailer against the dock

coupling the tractor to the second trailer

5 / 40

Select the true statement about converter dollies:

they typically require a glad hand converter

all answers listed

they usually do not have spring brakes

because of their small size they have little braking power

6 / 40

Remember to_____when steering to avoid a crash while driving doubles.

be prepared to counter-steer

all answers listed

have both hands on the steering wheel

keep your foot off the brake while turning

7 / 40

What is the minimum amount of distance you should maintain when driving at 50 mph in ideal conditions with a 100 ft twin trailer combination?

13 seconds

11 seconds

6 seconds

8 seconds

8 / 40

How do you release the dolly brakes when coupling twin trailers?

by opening the shut off valve

by flushing the brake line

by opening the air tank petcock

by charging the air line

9 / 40

You should look into the back of the fifth wheel on a dolly to see if it is locked onto the kingpin.

false

true

only at the end of a shift

only in a level loading dock

10 / 40

How do you secure a second trailer to your combination vehicle?

use the emergency air brakes or the trailer's spring brakes only

use wheel chocks only

use emergency air brakes, spring brakes, and wheel chocks together

none of the answers listed

11 / 40

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

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

nothing will occur

it is easier to countersteer doubles/triples than other vehicles

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

12 / 40

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

the rig will slide sideways but stay in a straight line

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

nothing will occur

there will be a trailer jackknife

13 / 40

What do yo uneed to do before supplying air to the air tanks of the second trailer?

close the shut off valves at the back of the second trailer and open the shut off valves at the back of the first trailer

open the shut off valves at the back of the first and second trailer

open the shut off vavles at the back of the second trailer and close the shut off valves at the back of the first trailer

close the shut off valves at the back of the first and second trailer

14 / 40

You should keep a minimum of ____between another vehicle and the double trailer with 100 ft truck driving at 30 mph.

13 seconds

8 seconds

15 seconds

10 seconds

15 / 40

What should you hear when you test the trailer brakes by opening the service air line at rear of trailer with the hand valve on?

you should hear air escape from the open valve

the emergency air line will release air

none of the answers listed

the service brakes will move to a fully applied position

16 / 40

The crack-the-whip effect is more likely to cause the front trailer to tip over.

there is an equal chance for trailers to tip

false

true

trailers never tip

17 / 40

You can be sure air is supplied to the second trailer by:

while driving at 10 mph apply the hand valve you should stop at the same in the same distance as a single trailer driving at 5 mph

you should get out and listen for air flowing through the lines

going to the rear of the second trailer and open the emergency line shut off

watch the air gauge for a drop of 30 psi

18 / 40

The trailer height is correct for connecting a converter dolly to a second trailer when:

the trailer will slightly lower when the converter dolly backed under it

the trailer will slightly rise when the converter dolly is backed under it

the top of the kingpin lines up with the locking jaws

the kingpin is resting behind the fifth wheel

19 / 40

How do you check the air flow to the last trailer?

pull the vehicle forward and then step on the brakes

listen for escaping air after opening the emergency shut off valve

while on an level surface, test the emergency brake lines

watch the brake lights as you step on the brake pedal

20 / 40

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

a fully loaded trailer behind the tractor

the last trailer of a triple

the last trailer of a double

any trailer

21 / 40

If you are driving a 100-foot truck with double trailers at 30 mph in dry conditions, how many seconds of space should there be between your truck and other vehicles?

22 / 40

You don't want to use wheel chocks when hooking a combination to a second trailer with no spring brakes. What should you do?

make sure the trailer will not roll away when coupling

supply air to the trailer air system via the tractor and then disconnect the emergency line

none of the answers listed

use a portable generator to supply brake pressure

23 / 40

What method should be used to test that the air is flowing to all the trailers?

only a certified mechanic can check for this

listen for air flow after opening the shutoff valves at the rear of the last trailer

pump the brakes with the windows down

check the pressure indicator dial on the final trailer

24 / 40

To be sure that air is supplied to the second trailer:

keep an eye of the air gauge for a drop of 30 psi

open the emergency line shut off at the back of the second trailer

crank the engine brake

while driving at 10 mph, use the hand valve. The vehicle should stop in the same distance of a single trailer moving at 5 mph

25 / 40

Which trailer is more likely to roll over when pulling 3 trailers?

the first trailer

the tractor

the last trailer

the second trailer

26 / 40

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

in a open position

in a closed position for the rear trailer and open position for the front trailers

in a open position for the rear trailer and a closed position for the front trailer

in a closed position

27 / 40

The correct trailer height when coupling the rear trailer is:

there is 5 inches of space between the lower and upper fifth wheel

when the locking jaws are open around the kingpin

the kingpin is touching the fifth wheel

slightly lower than the center of the fifth wheel

28 / 40

Select the statement that is true in regards to what is required of a driver with a double or triple trailers:

drive with extra care in mountains and in bad weather

none of the answers listed

all of the answers listed

increase your following distance

29 / 40

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

the last trailer of a double

the last trailer of a triple

the first trailer of a triples

the heaviest trailer

30 / 40

Select the true statement in regards to a converter dolly:

it is a connecting device consisting of one axle which disconnects a semitrailer combination vehicle converting it into two separate trailers

it is a coupling device with only two axles and a sixth wheel to which a semitrailer can be coupled to the rear of a tractor-trailer combination forming a double bottom rig

none of the answers listed

it is a coupling device with one or two axles and a fifth wheel with which a semitrailer can be coupled to the rear of a tractor-trailer combination forming a double bottom rig

31 / 40

How do you hook a combination to a second trailer without spring brakes and without using wheel chocks?

go ahead and couple it

disconnect the air supply lines after supplying air to the trailer air system via the tractor

have the trailer electric cord to a generator so it can supply braking power

make sure th trailer won't roll when coupling

32 / 40

When would a drive-wheel skid result in a jackknife when pulling doubles?

when the tractor spins around

when the trailer pushes the towed vehicle sideways

when the trailer slides to the right into the shoulder

when the tractor brakes lock up

33 / 40

How much space should you see between the lower and upper fifth wheel when checking the coupling of a converter dolly?

none

1 to 1 1/2 inches

it depends on how heavy the load is

1/2 to 1 inch

34 / 40

Why should you test the tractor protection valve?

to avoid the emergency brakes kicking on due to loss of air

to avoid loss of air from the trailer brakes

all answers listed

to avoid loss of air from the air hose

35 / 40

You should_____to uncouple the converter dolly.

chock the wheels, lower the landing gear, and disconnect the safey chains

chock the wheels, disconnect the safety chains, and then lower the landing gear

disconnect the safey chains, lower the landing gear, and chock the wheels

lower the landing gear, disconnect the safety chain, and chock the wheels

36 / 40

Select the true statement about seeing ahead.

good drivers will shift their attention from far and near and back and forth

all answers listed

you should look up to 1/4 mile ahead when driving at highway speeds

many individuals do not look far enough ahead while driving

37 / 40

How do you make sure the trailer height is correct before coupling?

visually check that they are level height wise

you do not need to do a visual check

visually check that the lead trailer is higher than the fifth wheel so that the trailer will lower when the dolly is pushed under it

visually check that the rear trailer is lower than the fifth wheel so that the trailer raises slightly when the dolly is pushed under it

38 / 40

Select the true statement about handling triples and doubles:

a tip over of the rear trailer can occur due to sudden movements of the steering wheel

because of the crack the whip effect, the rear trailer of a 100-foot triple is less likely to tip over

due to off-tracking, a triple bottom rig can come to a stop faster than a 5-axle tractor

triples and doubles handle the same as singles

39 / 40

Select the statement that is true in regards to managing space to the sides.

all answers listed

you should try to avoid driving next to others when possible

high gust winds do not cause any issues for triples and doubles

you should always keep your vehicle to the right side of the lane

40 / 40

Select the true statement in regards to driving a truck with triple or double trailers:

the risk of trailer jackknifes and tipping is increased compared to shorter trucks

CDL Double-Triple
Trailers Test

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