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

Why do air brakes take longer to stop than hydraulic brakes?

2 / 40

Select the false statement about suspension:

3 / 40

Select the answer that is not a part of the braking process when driving a tractor-trailer combination vehicle that has ABS:

4 / 40

Who is responsible for certifying on the bills of lading that the hazardous materials are prepared properly?

5 / 40

The direction of liquid movement not prevented by baffles is:

6 / 40

Which of the following parts do not get checked in the Bus Interior inspection:

7 / 40

What is the stopping distance for a tractor trailer that is traveling at 55 mph on dry pavement?

8 / 40

When driving tank vehicles you should:

9 / 40

The Emergency Response Guidebook (ERG):

10 / 40

The school bus driver may be the only contact person from school system some parents meet. The percentage of such parents is as high as:

11 / 40

At 55 miles-per-hour it takes about 6 seconds to stop a fully loaded truck and the braking distance is:

12 / 40

How high should you crank the landing gear?

13 / 40

If your bus is equipped with an emergency exit door, it must:

14 / 40

What does the drain valve for air tanks remove?

15 / 40

With the engine cut off and the brakes released the air loss in a straight truck or bus should not be more than:

16 / 40

It is very important that you never smoke around which hazard classes?

17 / 40

Select how you can tell if your vehicle is equipped with an anti-lock braking system:

18 / 40

What is most likely to occur when driving a tanker truck and the front wheels begin to skid?

19 / 40

A truck with baffles will handle:

20 / 40

What product is typically carried in a liquid tank trailer without baffles?

21 / 40

Which of the following are some suspension system defects?

22 / 40

If you are traveling at 55 mph in a 30-foot vehicle, you should leave how many seconds of following distance?

23 / 40

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

24 / 40

What are the 3 methods for securing a second trailer before coupling?

25 / 40

What is a king pin?

26 / 40

With most hazardous materials, you may park within 5 feet of the road briefly, if your work requires it. The materials that are the exception and do not allow parking this close to the road are:

27 / 40

How do you make sure the air lines are not crossed and the trailer brakes are working after supplying air to the trailer?

28 / 40

What is the most important reason for doing a school bus inspection?

29 / 40

Which of these is a good rule for backing a straight bus?

30 / 40

Always try to back toward the driver's side because

31 / 40

Select the factor that has no effect on how much liquid you can carry:

32 / 40

What is the next step after securing the bus when you have an unruly child on board?

33 / 40

What do you do first during step 3 of starting the engine and inspecting the inside of the cab?

34 / 40

Before transporting a sealed load, you must check:

35 / 40

The method used to make sure the spring brakes will come on automatically is to:

36 / 40

Select the true statement about tractor protection valve:

37 / 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?

38 / 40

The front trailer supports should be____before driving away.

39 / 40

Select the statement of what you should not do if you are required to drive through flowing water or deep puddles.

40 / 40

All standing riders must stay:

Your score is

The average score is 80%

5/5 - (2 votes)

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.