CDL (Commercial Driver's License) Practice Test (Doubles & Triples #2)


Welcome future truck drivers! The following is the CDL Doubles & Triples Practice Test #2. If you're going to drive a commercial vehicle with Doubles & Triples, you'll need an Doubles & Triples Endorsement on your CDL (Commercial Driver's License). Simply click in your answer (A,B,C, or D) to each CDL practice test question. When you're done, check your score and the results. You can reset the test and retake it as many times as you want.

CDL Doubles & Triples Practice Test #2

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1. When driving with more than one trailer, which trailer should be the first one behind the tractor?

A The lightest trailer
B The heaviest trailer
C The shortest trailer
D None of the above

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

A 9
B 10
C 11
D 12

3. 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 escape from the open valve
B The service brakes slowly move to the fully applied position
C The emergency line valve open and release air
D None of the above

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

A Push the brake pedal as hard as you can and hold it there
B Use only the trailer brakes
C Use controlled or stab braking
D None of the above

5. Converter dollies:

A Have little braking power because they are small
B Often do not have spring brakes
C Usually need a glad hand converter
D All of the above

6. The crack the whip effect that troubles trucks with trailers. Which is most likely to tip over:

A The rear trailer of a double
B A full trailer behind a truck
C The rear trailer of a triple
D Any trailer

7. 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
D Closed, free

8. When does the "driver's manual" advise disconnecting the steering axle brakes to help keep the rig straight?

A When the road is dry
B Any time you have to
C When the road is slippery
D Never

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

A The dolly tow bar may fly up
B The air lines will rupture
C The trailer brakes will unlock
D Nothing, the weight of the trailer will keep it in place

10. 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 It depends on the load
B None
C 1/2 to 3/4 of an inch
D 1/32 to 3/32 of an inch

11. Which of these statements about quick steering movements and doubles / triples is true?

A Countersteering is easier with doubles / triples than with most other vehicles
B You should put on the brakes at the same time you perform quick steering movements
C Doubles / triples are no problem with a quick steering move
D Doubles / triples flip over from quick steering moves more easily than many other vehicles

12. Empty trucks:

A May have poor traction due to bouncing and wheel lockup
B Stop in the same distance as a fully loaded one
C Require shorter stopping distances than full ones.
D Are the easiest to stop since there is no shifting cargo

13. You are driving a 100 foot truck with double trailers at 30 mph. The road is dry. Visibility is good. You should keep at least ____ seconds of space ahead of you:

A 9
B 10
C 11
D 12

14. If you want to couple a second trailer to your combination vehicle, secure it by using:

A The trailer's spring brakes and emergency air brakes
B Wheel chocks
C Either of the above, if available
D None of the above

15. The best way to stop all skids is to:

A Use stab or controlled braking
B Countersteer and accelerate
C Restore traction to the tires
D Steer and brake hard

16. Driving a truck with double or triple trailers requires a driver to:

A Use special care in bad weather and mountain conditions
B Allow more following distance than for smaller vehicles
C Both A and B
D None of the above

17. The best way to keep brakes from overheating while going down a steep grade is to:

A Use stab braking
B Use only the trailer brakes
C Use countersteering practices
D Go 5 m.p.h. below your safe speed

18. If you must drive through deep puddles or flowing water, which of these should you not do?

A Drive though quickly
B Use a lower gear
C Increase engine RPM
D Take advantage of the water and let it wash off your tires etc.

19. Some large trucks have convex or "spot" mirrors which:

A Make things look smaller and farther away than they really are
B Do not need to be checked as often as flat mirrors because they show a larger area
C Are against the law in most states
D Make things look larger and closer than the really are

20. Which of these statements about seeing ahead is true?

A At highway speed, you should look up to 1/4 mile ahead of your truck
B Many drivers do not look far enough ahead of their truck
C Good drivers shift their attention back and forth, near and far
D All of the above are true

21. When should you check your mirrors while making a lane change?

A After signaling the change
B Right after starting the lane change
C After completing the lane change
D All of the above

22. Which of these statements about managing space to the sides is true?

A Always keep your vehicle to the right side of your lane
B You should avoid traveling next to others when possible
C High winds are not a problem for doubles and triples
D All of the above

23. Which of these statements about handling of doubles and triples is true?

A The rear trailer of a 100 foot triple is less likely to turn over than a single semi trailer due to the crack the whip effect
B A triple bottom rig can stop quicker that a 5 axle tractor semi trailer due to off tracking
C A sudden movement with the steering wheel can result in a tipped over rear trailer
D None of the above

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

A Go to the rear of the second trailer and open the emergency line shut off
B Watch each trailer's air gauge for a drop of 30 psi
C Apply the hand valve at 10 mph. You should stop in the same distance as a truck with one trailer at 5 mph.
D Get out and listen for air flowing through the lines

25. You should check the height of the trailer before connecting a converter dolly to a second or third trailer. The trailer height is right when:

A The trailer will be raised slightly when the converter dolly is backed under it.
B The kingpin rests on the fifth wheel
C The center of the kingpin lines up with the locking jaws
D All of the above

26. 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
D Couple the trailer to the tractor, everything is ok

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

A Use the engine brake or speed retarder
B Use a light touch on the accelerator and brake pedals
C Keep other traffic out of you side space
D None of the above

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

A There is really no need to slow down for a curve
B Downshift after you enter the curve
C Braking during the turn
D Slowing to a safe speed before entering the curve, then accelerate slightly during the curve

29. You are driving a set of doubles. A set of trailer wheels goes into a skid. Which of these is most likely to occur?

A The rig will continue to move in a straight line no matter how much the steering wheel is turned.
B You will have a trailer jackknife
C The rig will stay in a straight line but slide sideways
D None of the above

30. Before you can supply air to the air tanks of a second trailer you need to:

A Open the shut off valves at the rear of the first trailer, and close the shut off valves at the rear of the second trailer
B Close the shut off valves at the rear of both trailers
C Open the shut off valves at the rear of both trailers
D None of the above

Score =

Correct answers:

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