CDL Practice Test


Idaho! 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

In what position should the converter dolly air tank drain valves and pintle hook be in?

2 / 40

Select the statement that is true in regards to quick steering movements and triple/double trailers:

3 / 40

Which of the following is NOT an important reason to look far ahead when you are driving?

4 / 40

Students exit the bus and walk:

5 / 40

The bolst, brackets, or bushings that attach the air bag and/or spring to the vehicle and axle frame are _____.

6 / 40

Why should you test the tractor protection valve?

7 / 40

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

8 / 40

The minimum tread depth for steering axle tires is:

9 / 40

Select the true statement:

10 / 40

The best way to have control on curves is:

11 / 40

How often should you check your cargo?

12 / 40

Which of the following is a key steering component?

13 / 40

The direction of liquid movement not prevented by baffles is:

14 / 40

You should adjust all the outside left and right side convex mirrors to see:

15 / 40

Urban mass transit coaches may have a brake and accelerator interlock system. Which of the following statements is true?

16 / 40

What does outage mean?

17 / 40

To decide which placards you need, if any, what three things do you need to know?

18 / 40

Select the true statement in regards to the liquid inside of a bulk tank causing a tank truck to roll sideways.

19 / 40

Air brake systems should not lose air faster than____when testing for air leakage rates in combination vehicles before applying the brake pedal.

20 / 40

Your bus starts to lean toward the outside on a banked curve, you are:

21 / 40

What keeps air in the tanks should the air compressor develop a leak?

22 / 40

A drawbridge does not have a traffic light showing green or a traffic control attendant. How many feet before the draw of a bridge must a bus driver stop?

23 / 40

Which signals may be used to warn of a stopped vehicle that contains explosives?

24 / 40

What does the amount of liquid allowed in the tank depend on?

25 / 40

Which of the following should you NOT do if you experience a tire failure?

26 / 40

How should the trailer be lined up when preparing to back the tractor up?

27 / 40

Select the true statement in regards to your brake function when your ABS fails

28 / 40

You should have the fifth wheel plate greased as recommened because:

29 / 40

What is the purpose of a driver placarding his or her vehicle?

30 / 40

In what location must you keep your shipping papers which describe any hazardous materials?

31 / 40

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

32 / 40

Select how brakes work on long, steep downgrades:

33 / 40

Select the portion of the combination vehicle that is most likely to turn over suddenly when pulling a double trailer:

34 / 40

Which of the following statements about downshifting is NOT true?

35 / 40

The most stable tanker shape is:

36 / 40

How should you know when to shift?

37 / 40

What school bus accidents should be reported?

38 / 40

What gauge on the dashboard indicates electrical system charging rate?

39 / 40

What is a passive railway crossing?

40 / 40

What is the purpose of a baffle?

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CDL Category Practice Tests

CDL Practice Test

How To Get A idaho Commercial Drivers License

Applicants can be age 18 or older when applying for their CDL. Those under the age of 21 are not eligible for the Hazmat or Doubles/Triples Endorsement. All applicants must get a DOT medical card to shows their ability to be physically able to drive a commercial motor vehicle.

Any drivers that fall into the following categories are disqualified from receiving their CDL:

  • Having more than one driver’s license.
  • Being convicted of an impaired driving offense in a commercial vehicle within the prior 24 months to submitting the CDL application.
  • Current suspended, revoked, denied, or canceled driver’s license.
  • Having CDL disqualifications in other states.

All applicants are required to complete a practical skills test and knowledge test in order to receive their CDL. Adding endorsements to a CDL will require additional knowledge tests and practical skills tests.

T – Doubles / Triples
P – Passenger
N – Tank Vehicles
H – Hazardous Materials
X – Tank Vehicle That Carries Hazardous Materials

Hit the Open Road

idaho CDL License Test Tips

Applicants for an Idaho CDL must complete a written knowledge test to showcase their retention of the commercial driving laws. Class A drivers are required to take a 70 question assessment that includes 20 questions specifically about combination vehicles. Class B and C applicants are required to pass a 50 question assessment. Those seeking endorsements and removal of the Air Brake Restriction must take additional tests that range between 20 and 30 questions. All tests must be passed with a score of 80 percent or better.

CDL applicants are required to pass a three-part skills test. These parts include a driving test, basic control skills test, and vehicle inspection test. This can be completed at an Idaho State Driving Facility or other approved testing site.

Additional Information

Information on the Idaho Transportation Department

The Idaho Transportation Department administers the CDL requirements and testing in Idaho. To get more information contact them via:


Phone:  208.334.8000


Additional Idaho CDL Helpful Links

Please use the links below to access more valuable Idaho CDL testing resources and to learn more about practice driving tests for the state of Idaho.