Combination #2
Combination Vehicles Practice Test | Idaho 2026 #2 Page 3 of 3
Train for FREE online with our Idaho CDL combination vehicle test. The official exam test consists of several obligatory parts, with all of them checking your knowledge of different blocks of road rules. If you need to obtain a ID combination license in 2026, practice as much as possible. Free sample tests published on our website will help you check and improve your knowledge and boost your grades. Please bear in mind that DMV requirements for issuing a combination license may vary from state to state.
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15 . The service air line is often controlled by the foot brake and is attached to the ____ valves.
The service air line carries air and is controlled by either the foot brake or trailer hand brake. The service air line is attached to relay valves, which allow the trailer brakes to be applied quickly.
16 . The trailer hand valve should be used:
The trailer hand valve (also referred to as the "trolley valve" or "Johnson bar") works the trailer brakes and should be used only when testing them. Using the trailer hand valve while driving could result in a skid.
17 . Rearward amplification refers to:
Vehicles with trailers are vulnerable to rollover due to the "crack-the-whip" effect, which is caused by rearward amplification.
18 . Pushing in the trailer air supply control will:
Push in the trailer air supply control to supply the trailer with air. Pull out the trailer air supply control to turn off the air supply and activate the emergency brakes.
19 . If a trailer begins to skid, it is best for the driver to:
If your trailer begins to skid, you should release the brakes to regain traction. The trailer will begin to straighten out once the wheels begin to grip the road again.
20 . Rearward amplification refers to:
The "crack-the-whip" effect is a result of rearward amplification. If not properly handled, a trailer can tip over due to rearward amplification.
2026 Idaho | Frequently Asked Questions
A CDL Class B license in Idaho allows the holder to operate single vehicles with a gross vehicle weight rating (GVWR) of 26,001 pounds or more, or a towed vehicle not exceeding 10,000 pounds GVWR. This includes straight trucks, large buses, segmented buses, and dump trucks with small trailers. A special endorsement may be needed for certain vehicles.
A Class B CDL license in Idaho allows the holder to operate single vehicles with a gross vehicle weight rating (GVWR) of 26,001 pounds or more, or tow a vehicle not exceeding 10,000 pounds GVWR. This includes straight trucks, large buses, segmented buses, farm labor vehicles, and dump trucks with small trailers. Special endorsements may be required for certain vehicles.
To acquire a Class B CDL license in Idaho, the applicant must be at least 18 years old for intrastate transport and 21 for interstate transport. They must pass a vision test, obtain a Medical Examiner's Certificate, pass a General Knowledge test, and a skills test which includes pre-trip inspection, basic controls, and on-road driving. Prior to testing, applicants need a Commercial Learner's Permit (CLP).
In Idaho, you must be at least 18 years old to qualify for a Class B CDL license for intrastate transport (within Idaho only). However, if you intend to drive interstate (across state lines), you must be at least 21 years old. These age requirements are set by the Federal Motor Carrier Safety Administration.
Specific endorsements aren't necessary for a Class B CDL license in Idaho, but they can broaden the range of vehicles you can operate and materials you can transport. These endorsements include passenger, school bus, tanker, hazardous materials (HazMat), and double/triple trailers. To get these endorsements, you must pass additional knowledge and skills tests.
The Class B CDL skills assessment in Idaho includes a pre-trip vehicle inspection, a basic vehicle control test, and an on-road driving test. You'll demonstrate your ability to inspect your vehicle, control its operation, and drive it safely in various road and traffic conditions. The specific maneuvers and operations you'll perform depend on the type of vehicle you're testing in.
Yes, Class B CDL license holders in Idaho are limited to operating vehicles with a gross vehicle weight rating (GVWR) of 26,001 lbs or more, or a vehicle towing another vehicle not exceeding 10,000 lbs GVWR. They cannot drive Class A vehicles (tractor-trailers) without the appropriate license. Also, without specific endorsements, they cannot transport hazardous materials or more than 15 passengers.
In Idaho, the written CDL test is primarily offered in English. However, some locations may offer the test in Spanish. It's important to note that all CDL applicants must pass an English proficiency test, as federal regulations require drivers to read and speak English to ensure road safety. Always check with your local DMV for available language options.
Yes, you can request test accommodations for the Class B CDL written exam in Idaho due to disability. The Idaho Transportation Department adheres to the Americans with Disabilities Act (ADA) and provides reasonable accommodations. However, you must provide documentation to verify your disability. Contact your local DMV office to discuss your specific needs and to ensure the right accommodations are made.
If you fail the Class B CDL written test in Idaho, you can retake it. However, you must wait at least three days before you can try again. Keep in mind that each attempt may require an additional fee. It's recommended to study thoroughly using the Idaho CDL manual and online practice tests to increase your chances of passing on the next attempt.