Combination Vehicles Practice Test | Idaho 2025 #1

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 2025, 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.

Number of Question 20

Passing Score 16

Number of Tests 20

1 . In a vehicle equipped with an automatic tractor protection valve, the valve will pop out when air pressure drops to a level between:

20 and 45 psi.

75 and 105 psi.

50 and 65 psi.

In vehicles equipped with an automatic tractor protection valve, the valve will pop out if air pressure drops to a level between 20 and 45 psi. When the valve pops out, the protection valve will close, stopping the flow of air.

2 . Combination vehicles:

Often have taller trailers than single commercial vehicles.

Are usually lighter than single commercial vehicles.

Require more skill to drive than single commercial vehicles.

Driving combination vehicles requires more skill than driving single commercial vehicles. Combinations are generally longer, generally heavier, and are more vulnerable to rollover.

3 . When connecting a converter dolly to a second trailer, the trailer height should be ____ the center of the fifth wheel.

Level with

Slightly higher than

Slightly lower than

When connecting a converter dolly to a second or third trailer, the trailer height should correct. It should be slightly lower than the center of the fifth wheel.

4 . Rearward amplification refers to:

The amount of noise projected to the rear of a vehicle.

The cause of the "crack-the-whip" effect.

The number of trailers that can be pulled by a tractor.

Vehicles with trailers are vulnerable to rollover due to the "crack-the-whip" effect, which is caused by rearward amplification.

5 . Trailers built before ____ are not required to have spring brakes.

1985

1975

1999

Trailers built before 1975 are not required to have spring brakes. When parking a trailer without spring brakes, be sure to use wheel chocks to prevent the trailer from rolling.

6 . How much space should be between the upper and lower fifth wheel?

About five inches of space

A maximum of two inches of space

No space

Before a trip, be sure to inspect all couplings. There should be no space between the upper and lower fifth wheel.

7 . The service air line is often controlled by the foot brake and is attached to the ____ valves.

Relay

Supply

Emergency

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.

Study tip:

Reduce your study time from hours to minutes with a DMV exam “Cheat Sheet”

99.2% of people who use the cheat sheet pass the FIRST TIME

Click Here
Full Cheat Sheet

99.2%

99.2% of people who use the cheat sheet pass the FIRST TIME

2025 Idaho | Frequently Asked Questions

To secure a CDL Bus endorsement in Idaho, you must first have a Commercial Driver's License (CDL). Next, you'll need to pass a passenger endorsement test covering topics like vehicle inspection, loading/unloading passengers, and emergency procedures. You also need to pass a skills test in a vehicle similar to the one you'll be driving. Check with the Idaho Transportation Department for more details.

To obtain a CDL Bus license in Idaho, you need to have a valid driver's license, pass a physical examination, and complete a CDL training course. Afterward, you'll take a written knowledge test and a skills test, which includes pre-trip vehicle inspection, basic vehicle control, and on-road driving. You also need to pass the Passenger Endorsement test for bus drivers.

Yes, training is necessary for a CDL Bus endorsement in Idaho. You must complete a CDL training course that includes both classroom instruction and behind-the-wheel training. After the course, you'll need to pass a written knowledge test and a skills test. Some employers may also require previous driving experience. Check with the Idaho Transportation Department for specific requirements.

CDL Bus licenses in Idaho are categorized into three classes based on the vehicle's size and purpose: Class A, B, and C. Class A is for vehicles over 26,001 pounds or towing over 10,000 pounds. Class B is for vehicles over 26,001 pounds or towing vehicles less than 10,000 pounds. Class C is for transporting 16 or more passengers (including driver) or hazardous materials.

No, you cannot use your personal vehicle for the CDL Bus driving test in Idaho. The vehicle you use for the test must match the class and type of vehicle you plan to drive with your CDL. Therefore, you must use a commercial bus for your bus endorsement driving test. This ensures that you can handle the size and complexity of such vehicles.

During the CDL Bus driving test in Idaho, examiners assess your ability to safely operate a commercial bus. Skills evaluated include pre-trip vehicle inspection, basic vehicle control (like turning, stopping, and backing up), and on-road driving (like lane changes, intersections, and highway driving). You'll also be tested on specific bus operations like loading/unloading passengers, railroad crossing procedures, and emergency exit procedures.

Yes, to obtain a CDL Bus endorsement in Idaho, you must meet specific medical requirements. You're required to pass a Department of Transportation (DOT) physical examination every 24 months to ensure you're physically capable of safe driving. The exam covers vision, hearing, blood pressure, and checks for conditions like diabetes or epilepsy that could interfere with driving safety.

No, it is not permissible to transport passengers without a valid CDL Bus endorsement in Idaho. The law requires any driver operating a commercial vehicle designed to carry 16 or more passengers, including the driver, to hold a valid Commercial Driver's License (CDL) with a Passenger (P) endorsement. Operating without this could lead to serious legal consequences.

Yes, the CDL Bus endorsement can be added to your existing CDL. In Idaho, you don't need to apply for a new license. However, you're required to pass the passenger transport test, and in some cases, a driving skills test in the type of vehicle you will be driving. Once you pass, the endorsement is added to your CDL.

Yes, drivers with a CDL Bus endorsement in Idaho must adhere to certain restrictions. They must not have more than one serious traffic violation in three years, and must not have any DUI convictions in the past five years. Additionally, they must pass the required knowledge and skills tests, maintain a clean driving record, and meet physical qualification standards.