DMV CDL Practice Test 3 - Doubles / Triples

1 / 20

How can you be sure you supplied air to a second trailer?

A. Apply the hand valve at 10 MPH, you should stop in the same distance as a truck with one trailer at 5 MPH

B. Watch each trailers air gauge for a drop of 30 PSI

C. Go to the rear of the second trailer and open the emergency line shut off

Use the tractor parking brake and/or chock the wheels to hold the vehicle. Wait for air pressure to reach normal, then push in the red "trailer air supply" knob. This will supply air to the emergency (supply) lines. Open the emergency line shut-off valve at the rear of the last trailer. You should hear air escaping, showing the entire system is charged.

2 / 20

If a converter dolly is still under the second trailer and you unlock the pintle hook, what will probably happen?

A. The airlines will rupture

B. The trailer brakes will unlock

C. The dolly tow bar may fly up

Never unlock the pintle hook with the dolly still under the rear trailer. The dolly tow bar may fly up, possibly causing injury, and making it very difficult to re-couple.

3 / 20

You are visually checking the coupling of a converter dolly to the rear trailer. How much space should be between the upper and lower fifth wheel?

A. 1/2 to 3/4 inch

B. None

C. It depends on the load

Check that the trailer is lying flat on the fifth wheel skid plate with no gap.

4 / 20

When you uncouple twin trailers, the last step is to

A. slowly pull clear of the converter dolly

B. uncouple the converter dolly

C. release the brakes on the converter dolly

Slowly pull clear of dolly.

5 / 20

Converter dollies

A. sometimes do not have antilock brakes

B. have little braking power because they are small

C. usually need a glad hand converter

All converter dollies built since 1998 are required to have antilock brakes

6 / 20

You want to hook your combination to a second trailer that has no spring brakes. To do this without wheel chocks you should:

A. Make sure the trailer will roll freely when coupling

B. Hook the trailer electric cord to a portable generator for braking power

C. Supply air to the trailer air system with the tractor and then disconnect the emergency line

If the second trailer doesn't have spring brakes, drive the tractor close to the trailer, connect the emergency line, charge the trailer air tank, and disconnect the emergency line. This will set the trailer emergency brakes if the slack adjusters are correctly adjusted.

7 / 20

Empty trucks:

A. Are the easiest to stop since there is no shifting cargo

B. Require shorter stopping distances than full ones

C. May have poor traction due to bouncing and wheel lockup

Empty trucks require greater stopping distances because an empty vehicle has less traction.

8 / 20

When parking your double or triple combination, you should look for a parking space

A. that is as close as possible to your destination

B. that you can pull straight through

C. that you can back out of.

Make sure you do not get in a spot you cannot pull straight through. You need to be aware of how parking lots are arranged to avoid a long and difficult escape

9 / 20

With the hand valve on, you should test the trailer brakes by opening the service line valve at the rear of the rig. When you do this, you should hear:

A. Air escapes from the open valve

B. The emergency line valve open and release air

C. The service brakes slowly move to the fully applied position

Open the service line valve, listen for air to escape, and then close the valve.

10 / 20

Which of these in not a good thing to do when driving on slippery roads?

A. Use the engine brake or speed retarder

B. Keep other traffic out of you side space

C. Use a light touch on the accelerator and brake pedals

When your drive wheels have poor traction, the retarder may cause them to skid. Therefore, you should turn the retarder off whenever the road is wet, icy, or snow covered.

11 / 20

Double and triple combination vehicles are ________ stable than other types of commercial vehicles.

A. neither more nor less

B. more

C. less

Take special care when pulling two and three trailers. There are more things that can go wrong, and doubles/triples are less stable than other commercial vehicles.

12 / 20

You are driving a 100-foot twin trailer combination at 50 mph. The road is dry, and visibility is good. You should keep at least _____ seconds of space ahead of you.

A. 11*10

B. 12

One good rule says you need at least one second for each 10 feet of vehicle length at speeds below 40 mph. At greater speeds, you must add 1 second for safety.

13 / 20

You are driving a 100-foot twin trailer combination at 50 mph. The road is dry, and visibility is good. You should keep at least _____ seconds of space ahead of you.

A. 12

B. 10

C. 11

One good rule says you need at least one second for each 10 feet of vehicle length at speeds below 40 mph. At greater speeds, you must add 1 second for safety.

14 / 20

Which of these in not a good thing to do when driving on slippery roads?

A. Keep other traffic out of you side space

B. Use a light touch on the accelerator and brake pedals

C. Use the engine brake or speed retarder

When your drive wheels have poor traction, the retarder may cause them to skid. Therefore, you should turn the retarder off whenever the road is wet, icy, or snow covered.

15 / 20

Which of these will result in the best control on curves?

A. Braking during the turn

B. Downshift after you enter the curve

C. Slowing to a safe speed before entering the curve, then accelerate slightly during the curve

Slow down to a safe speed, and downshift to the right gear before entering the curve. This lets you use some power through the curve to help the vehicle be more stable while turning.

16 / 20

You are driving with double trailers and must use your brakes to avoid a crash. For emergency braking you should:

A. Use only the trailer brakes

B. Push the brake pedal as hard as you can and hold it there

C. Use controlled or stab braking

You should brake in a way that will keep your vehicle in a straight line and allow you to turn if it becomes necessary. You can use the controlled braking method or the stab braking method.

17 / 20

You are doing a walk around inspection of a double or triple trailer rig. You should be sure the converter dolly air tank drain valves are _ and the pintle hook is _.

A. Open, latched

B. Open, free

C. Closed, latched

Converter dolly air tank drain valve are closed, and make sure pintle hook is latched.

18 / 20

During an inspection of a double or triple combination, check the usual things for any combination vehicle and check

A. the shut-off valves, the converter dolly or dollies, and the air brakes on all trailers

B. the trailers and the radios in the tractor

C. the fifth wheel and the landing gear

To inspect a double or triple, first inspect it just as you would inspect any combination vehicle. Then check that the shut-off valves are open on all trailers but the last trailer. Check each converter dolly to be sure that the pintle hook is properly latched.

19 / 20

You have connected the converter dolly to the front semitrailer and then connected the rear semitrailer to the converter dolly. How should you test the coupling?

A. Drive forward slowly and see if the rear semitrailer stays attached

B. Pull against the rear semitrailer's pin

C. Drive forward, brake suddenly, and see if the rear semitrailer hits the one in front of it

Test coupling by pulling against pin of the rear semitrailer

20 / 20

The first step in uncoupling a converter dolly is

A. to lower its landing gear

B. to slowly pull clear of it.

C. to disconnect the safety chains

Lower dolly landing gear.

Mississippi's CDL Practice Test 3

How can you be sure you supplied air to a second trailer?

If a converter dolly is still under the second trailer and you unlock the pintle hook, what will probably happen?

You are visually checking the coupling of a converter dolly to the rear trailer. How much space should be between the upper and lower fifth wheel?

When you uncouple twin trailers, the last step is to

Converter dollies

You want to hook your combination to a second trailer that has no spring brakes. To do this without wheel chocks you should:

Empty trucks:

When parking your double or triple combination, you should look for a parking space

With the hand valve on, you should test the trailer brakes by opening the service line valve at the rear of the rig. When you do this, you should hear:

Which of these in not a good thing to do when driving on slippery roads?

Double and triple combination vehicles are ________ stable than other types of commercial vehicles.

You are driving a 100-foot twin trailer combination at 50 mph. The road is dry, and visibility is good. You should keep at least _____ seconds of space ahead of you.

You are driving a 100-foot twin trailer combination at 50 mph. The road is dry, and visibility is good. You should keep at least _____ seconds of space ahead of you.

Which of these in not a good thing to do when driving on slippery roads?

Which of these will result in the best control on curves?

You are driving with double trailers and must use your brakes to avoid a crash. For emergency braking you should:

You are doing a walk around inspection of a double or triple trailer rig. You should be sure the converter dolly air tank drain valves are _ and the pintle hook is _.

During an inspection of a double or triple combination, check the usual things for any combination vehicle and check

You have connected the converter dolly to the front semitrailer and then connected the rear semitrailer to the converter dolly. How should you test the coupling?

The first step in uncoupling a converter dolly is

Result:

Mississippi's CDL Practice Test 3

How can you be sure you supplied air to a second trailer?

If a converter dolly is still under the second trailer and you unlock the pintle hook, what will probably happen?

You are visually checking the coupling of a converter dolly to the rear trailer. How much space should be between the upper and lower fifth wheel?

When you uncouple twin trailers, the last step is to

Converter dollies

You want to hook your combination to a second trailer that has no spring brakes. To do this without wheel chocks you should:

Empty trucks:

When parking your double or triple combination, you should look for a parking space

With the hand valve on, you should test the trailer brakes by opening the service line valve at the rear of the rig. When you do this, you should hear:

Which of these in not a good thing to do when driving on slippery roads?

Double and triple combination vehicles are ________ stable than other types of commercial vehicles.

You are driving a 100-foot twin trailer combination at 50 mph. The road is dry, and visibility is good. You should keep at least _____ seconds of space ahead of you.

You are driving a 100-foot twin trailer combination at 50 mph. The road is dry, and visibility is good. You should keep at least _____ seconds of space ahead of you.

Which of these in not a good thing to do when driving on slippery roads?

Which of these will result in the best control on curves?

You are driving with double trailers and must use your brakes to avoid a crash. For emergency braking you should:

You are doing a walk around inspection of a double or triple trailer rig. You should be sure the converter dolly air tank drain valves are _____ and the pintle hook is _____.

During an inspection of a double or triple combination, check the usual things for any combination vehicle and check

You have connected the converter dolly to the front semitrailer and then connected the rear semitrailer to the converter dolly. How should you test the coupling?

The first step in uncoupling a converter dolly is

Result:

You are doing a walk around inspection of a double or triple trailer rig. You should be sure the converter dolly air tank drain valves are _ and the pintle hook is _.