Combination #1
Combination Vehicles Practice Test | Iowa 2026 #1 Page 3 of 3
Train for FREE online with our Iowa 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 IA 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 . Having anti-lock brakes on only one axle:
If a vehicle has anti-lock brakes on just one axle, the driver will still have more control during braking than they would without any anti-lock brakes.
16 . A driver should test the tractor protection valve by:
You should test the tractor protection valve by allowing the air supply to properly charge, turning off the engine, then releasing air from the system by pressing the brake pedal several times. The tractor protection valve should move into its emergency position when psi drops to an unsafe level.
17 . A trailer that is too high:
Before coupling together a tractor and a trailer, you should make sure the trailer is at the proper height. If the trailer is too low, the trailer nose may be damaged. If the trailer is too high, it may not be able to couple correctly.
18 . 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.
19 . Older trailers are not equipped with spring brakes. This means that if the air supply for a vehicle's air braking system leaks away:
Older trailers do not have spring brakes. This means that if the air supply in an older trailer's air tank has leaked away, there will be no working brakes connected to the trailer and its wheels will turn freely.
20 . If the emergency air line loses pressure:
The emergency air line controls the emergency brakes on a combination vehicle. A loss of air pressure in the emergency line will cause the emergency trailer brakes to activate.
See the exact questions that will be on the 2026 Iowa DMV exam.
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2026 Iowa | Frequently Asked Questions
To secure a CDL Bus endorsement in Iowa, you must first hold a valid Commercial Driver's License (CDL). You then need to pass the Passenger Transport Test, undergo a physical examination, and complete a skills test in the type of vehicle you'll be driving. Finally, you must pass a background check as mandated by Federal Motor Carrier Safety Administration.
To obtain a CDL Bus license, you must first have a valid driver's license. Then, pass the CDL general knowledge test, and the passenger transport test. You must also pass a physical examination and a skills test in the type of bus you will be driving. Finally, submit to a background check as required by the Federal Motor Carrier Safety Administration.
Yes, specific training is necessary for a CDL Bus endorsement. You must complete a commercial driver's education course, pass the general knowledge and passenger transport written tests, and successfully complete a skills test in the type of bus you'll be driving. Some states also require applicants to have a certain amount of driving experience.
CDL Bus licenses are classified into three main categories: Class A, B, and C. Class A is for vehicles with a combined weight over 26,001 lbs where the vehicle being towed is over 10,000 lbs. Class B is for single vehicles over 26,001 lbs not towing a vehicle over 10,000 lbs. Class C is for vehicles carrying 16 or more passengers including the driver or hazardous materials.
No, you cannot use your personal vehicle for the CDL Bus driving test. The test must be taken in the same type of vehicle for which you are trying to get licensed. This means you will need to take the test in a commercial bus similar to the one you will be driving professionally.
During the CDL Bus driving test, you'll be evaluated on several skills. These include pre-trip vehicle inspection, basic vehicle control (backing, turning, stopping), and on-road driving (including highway, city, and residential driving). You'll also be tested on specific bus maneuvers such as loading and unloading passengers, bus stop procedures, and emergency exit procedures.
Yes, there are additional medical prerequisites for a CDL Bus endorsement. You must pass a Department of Transportation (DOT) physical exam every 24 months. The exam assesses hearing, vision, blood pressure, and checks for conditions like diabetes or epilepsy that could affect your ability to safely operate a bus.
No, it's not permissible to transport passengers without a valid CDL Bus endorsement in Iowa. It's a requirement by law for drivers who operate a vehicle designed to carry 16 or more passengers, including the driver. Driving such a vehicle without the proper endorsement could result in serious legal consequences, including fines and suspension of your driving privileges.
Yes, the CDL Bus endorsement can be added to your existing CDL in Iowa. You don't need to apply for a new license, but you must pass the Passenger Transport test. Once you pass, the endorsement will be added to your current CDL. However, you may need to renew your license if it's close to its expiration date.
Yes, drivers with a CDL Bus endorsement must comply with federal and state regulations. These include maintaining a logbook of hours driven, undergoing regular medical examinations, and adhering to restrictions on alcohol consumption. Also, some states may have additional restrictions such as age limits and mandatory rest periods between driving shifts.
