CDL (Commercial Driver's License) Practice Test (Combination Vehicles #1)

Welcome future truck drivers! The following is the CDL Combination Vehicles Practice Test #1. 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 Combination Vehicles Practice Test #1 Start Now 1. When uncoupling, it's a good practice to... A couple the glad hands together B couple the glad hands to dummy couplers C hang the electrical cable with the plug end down D all of the above are acceptable 2. If you cross your air lines on a new trailer with spring brakes... A you won't be able to release the trailer brakes B you won't be able to release the tractor brakes C you won't have any operational brakes D you'll have no way of knowing there's a problem 3. When traveling under 40 mph, you should follow other vehicles... A Only during the day B With a distance of one second for every ten feet of your vehicle length C With a distance of one second for every twenty feet of your vehicle length D As close as possible so others don?t cut in 4. In order to supply air to the trailer, you must first... A Push in the tractor protection valve. B Pull out the "air supply' knob C Stop engine so you can hear the brakes D Cross the air lines to check for leaks 5. If one of the glad hands on your blue air line is missing a seal... A take one off the red air line and use that as a temporary replacement B you might end up with a service line air leak C you could experience an emergency line air leak D it's not a major problem and you should continue coupling 6. When you inspect the coupling, check to ensure that... A there's a little slack in the air lines B there's no slack in the air lines C the landing gear handle is hanging free D the electrical cable is unplugged 7. The trailer hand valve should be used... A Only at highway speeds B Only when parking C Only to test the trailer brakes D Both B & C above 8. Which one of the following statements about tractor protection valves is NOT true? A It keeps air in the tractor in the event the trailer air leaks B It is controlled by the trailer air supply valve in the cab C When it closes it allows air to leak from the tractor line D It will close automatically if air pressure is low 9. You can damage the landing gear if you... A back under the trailer at an angle B align the tractor and trailer C position the trailer kingpin in the center of the fifth wheel D back under the trailer in a straight line 10. Which one of the following is controlled by the foot brake? A The service air line B The emergency air line C The shut off valve D The hose coupler 11. When uncoupling, if you park the trailer at an angle... A you won't have to do as much walking around the vehicle B you'll have more room to maneuver in the yard C you'll make the process easier D you could do damage to the landing gear 12. If you start a trailer skid you should... A Step on the brakes quickly B Release the brakes to get traction back C Use the trailer hand brake D Slowly apply pressure to the brakes 13. When coupling the glad hands, you should NOT do the following... A Clean the couplers before a connection is made B Press the two seals together at a 90 degree angle C Cross air supply lines to test them for leaks D Match the colors to each other, or read the tags before connecting 14. If you cross connect the two air lines the following will result... A Nothing, the lines are interchangeable B You will not have air going to the trailer brakes C Your tractor brakes will lock up D You could not move the tractor 15. When rolling up the landing gear to complete the coupling process... A leave the landing gear half way down to make uncoupling easier later B use low gear until the tractor is supporting the trailer C use high gear to speed up the process D grease the landing gear to speed up the process 16. When coupling the trailer, back up slowly until... A The load shifts inside the trailer B The fifth wheel just touches the trailer C You can see the rear wheels in the mirror D You hit the front of the trailer with the tractor 17. The earliest way to notice a trailer skid is... A By feeling the pull on your steering wheel B By feeling a jerking in the back of the tractor C By seeing it in your mirrors D By hearing the squeal from the tires 18. A king pin is... A The pin which locks the air brake lines together B A pin which locks the trailer to the tractor on the fifth wheel C A pin which holds the wheels on the axles D The pin a driver receives for safe driving 19. The trailer should be lowered so that... A the trailer is far above the fifth wheel B the tractor strikes the nose of the trailer C you can use the landing gear to make any adjustments D it's raised slightly when the tractor's backed under it 20.Which of the following steps comes first? A apply the trailer brakes B raise the landing gear C put the transmission in reverse D connect the air supply lines 21. Before you begin coupling... A check the condition of the tractor frame B check your path for hazards C pre-position the fifth wheel D put the spring brakes on 22. The trailer air supply control... A Is a red, triangular-shaped knob B Is a yellow, square knob C Is a red, square knob D Is a red, eight sided knob 23. In order to inspect the coupling you should... A Make sure there is space between the upper and lower fifth wheel B Check that the locking lever is in the open position C Make sure the fifth wheel jaws are open D Use a flashlight if necessary 24. You should crank the landing gear until... A It is six inches off the ground B You can clear railroad tracks C The crank handle is loose D It is as far up as it will go 25. The fifth wheel should be checked to see if... A There is damage or missing parts B It is properly greased C The jaws are open D All of the above 26. A device which connects the service and emergency air lines from the truck to the trailer is called... A Relay switch B Glad hands C Service couplers D Shut off valves 27. The service air line is controlled by... A The pressure applied to the line by the foot brake or the trailer hand brake B The relay valve which connects the trailer air tanks to the trailer air brakes C The relay valve which sends air pressure from the trailer air tank to the trailer brake chambers D All of the above 28. To prevent rollovers, remember to... A Keep the load centered B Keep the load as low as possible C Go slow around turns D All of the above 29. "Off-tracking" occurs when you go around a corner and... A The rear wheels follow a different path than the front wheels B The rear trailer goes off the road C The rear wheels follow the front ones in a straight line D The front of the trailer pulls to the right 30. Large combination vehicles take longer to stop... A When they are empty B When they are loaded C Than bobtail tractors D It takes the same time whether empty or loaded Score = Correct answers: Get My CDL! The New Trucker Career Center CDL Practice Tests Access Page Trucker Country Home Page Choose from these additional practice tests... CDL General Knowledge Practice Test #1 CDL General Knowledge Practice Test #2 CDL Hazardous Materials Practice Test #1 CDL Hazardous Materials Practice Test #2 CDL Air Brakes Practice Test #1 CDL Air Brakes Practice Test #2 CDL Doubles and Triples Practice Test #1 CDL Doubles and Triples Practice Test #2 CDL Combination Vehicles Practice Test #2 CDL Tank Vehicles Practice Test #1 CDL Tank Vehicles Practice Test #2 Jim Purcell, President of Trucker Country, has put together the ultimate series of trucking guides for anyone interested in a career as a professional trucker. Whether you're just curious about trucking or you're ready to become a successful truck driver, you'll find all the real-world information you need in this amazing series of guides. Learn, step-by-step: the truth about the world of trucking, how to become a trucker, and even how to succeed at the trucking job and life.

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