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Free Idaho CDL Combination Practice Test 2025

Part of mandatory Entry-Level Driver Training Course Based on 2025 ID commercial driver's license manualAvailable in EN, ES
25questions
5mistakes allowed
80%passing score

Are you studying to pass the official Idaho Combination Vehicles knowledge test (which is a a necessary step to drive semi-trucks and tractor-trailers)? Worried that you may not pass without some additional help? We’re glad you chose us to help you, because we’re sure you won’t be disappointed. Many other aspiring truck drivers couldn’t quite master commercial driving theory just by reading the official Idaho Commercial Driver’s License Manual (Idaho CDL Handbook 2025). That’s why many of them chose to supplement their reading of this study guide with other study tools – such as the ones we offer.

This free Idaho CDL Combination practice test is based on the official manual, just like the official Combination Vehicles knowledge test. And the practice test is up to date as of January, 2025. Practicing with it will help reinforce what you read in the CDL manual. In addition, each of the 25 practice questions comes with a helpful hint and an explanation of the correct answer. The practice questions and answers on this test will assess your knowledge of such topics as combination braking systems, combination driving techniques, coupling and uncoupling, and pre-trip inspections. Keep practicing your knowledge with as many of our practice tests as you can, as often as you can, until you feel confident that you’ve mastered the material and can ace the official Combination Vehicles knowledge test.

Once you pass this knowledge test and get the appropriate class of Commercial Driver’s License (CDL) and any endorsements you need, you can start taking advantage of profitable opportunities in combination truck driving. Idaho produces huge quantities of agricultural products: most famously potatoes, but also wheat, barley, and dairy products, all of which require truck drivers to transport. Folks who don’t live in Idaho may think of it as just an agricultural state, but the state also has a large and growing industrial sector, especially in science and technology. High-tech businesses require truck drivers to transport equipment and supplies to them as well as transport their finished products. Other important economic sectors include logging (lumber and wood products) and silver and other mining. These types of businesses also need truckers to transport these raw materials.

Major trucking routes include Interstates 15 (Montana to California), 84 (Oregon to Utah), and 90 (Washington State to Massachusetts); U.S. Routes 20 (Oregon to Massachusetts) and 95 (Idaho to Arizona); and State Route 55 (connects with U.S. 95 at both ends).

4.75 out of 5 • 8 votes.

Perfect for

  • First-time ID CDL and CLP applicants
  • CDL holders adding endorsements
  • ID CDL renewal applicants
ID commercial driver's license

What to expect on the actual exam

How many questions20
How many correct answers to pass16
Passing score80%
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List of questions (classic view)

  1. After you lock the kingpin into the fifth wheel, how should you check the connection?
  2. After you connect the air lines but before you back under the trailer, you should
  3. Which statement best illustrates the "crack-the-whip" effect?
  4. When you inspect the landing gear after uncoupling the trailer, where should the tractor be?
  5. What is the safest way to turn right from a two-way road?
  6. To drive a triple combination vehicle, you must have
  7. To prevent a rollover, cargo should be
  8. Combination vehicles take longer to stop when they are empty than when they are fully loaded, because
  9. If your vehicle gets stuck on a railroad track, you should
  10. Low-slung vehicles can be risky at railroad crossings because
  11. On a double or triple vehicle, which wheels offtrack the most?
  12. When you're pulling doubles or triples, the shut-off valves should always be
  13. On a trailer, where is the yellow antilock brake (ABS) malfunction lamp located?
  14. Even before antilock braking systems (ABS) were required, some vehicles already had them. How can you check if your vehicle has ABS?
  15. An antilock braking system (ABS) is useful
  16. After coupling, make sure that the air lines are not crossed. How should you do this?
  17. During uncoupling, you should disconnect the electrical cable and
  18. Before you start to uncouple, you must
  19. You can confirm that air is going to all brakes in your trailers by
  20. To uncouple a loaded trailer, after the landing gear has made firm contact with the ground, you should
  21. If the trailer has antilock brakes (ABS) but the tractor doesn't,
  22. To test the tractor protection valve, charge the trailer air brake system, turn off the engine, and
  23. If your test of the tractor protection valve is successful,
  24. The tractor protection valve is designed to close automatically if the air pressure falls into the pressure range specified by the manufacturer, typically
  25. As part of your vehicle inspection test, if your vehicle is equipped with air brakes and has a trailer, you will inspect the air connections between the truck or tractor and the trailer. Make sure that the ________ are locked in place and free of damage or air leaks.

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