Double Triple Test | Iowa 2025 #2

Train for FREE with our Iowa CDL double triple practice test online. 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 CDL double triple 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 may vary from state to state.

Number of Question 20

Passing Score 16

Number of Tests 20

1 . What is a drawback of retarders?

They may not be permitted everywhere.

They can help to slow a vehicle.

They cannot be turned off.

A retarder is a device that helps to slow a vehicle, reducing the need for a driver to use the brakes. However, these devices can be noisy and are not permitted everywhere.

2 . The air storage tanks:

Hold only enough air for one braking cycle.

Hold enough air for the brakes to be used several times if the compressor stops working.

Do not hold air unless there is an emergency.

The air storage tanks in an air brake system store compressed air to be used for braking. They hold enough air for the brakes to still be used several times if the compressor stops working.

3 . When should mirrors be adjusted?

Before driving

While driving

After driving

The adjustment of your mirrors should be checked prior to the start of all trips. Adjust your mirrors as needed.

4 . A low air pressure warning signal should activate:

When tank pressure falls below 120 psi.

When tank pressure falls below 60 psi.

When tank pressure falls below 10 psi.

When tank pressure falls below 5 psi.

In an air brake system, a low air pressure warning signal must come on if air pressure in the tanks falls below 60 psi. This warning signal may come in the form of a light, a buzzer, or a wig wag.

5 . If the emergency air line loses pressure:

The Anti-Lock Braking System will activate.

The service air line will activate.

The emergency brakes will activate.

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.

6 . When traveling through a work zone, you should:

Slow down.

Speed up.

Steer with one hand and keep the other hand free.

Always observe posted speed limits for work zones. Slow down if road or weather conditions are adverse, and slow down even more if workers are on or near the road.

7 . If your vehicle is hydroplaning, you should:

Turn the steering wheel as hard as possible.

Not use the brakes.

Put the vehicle in reverse.

If your vehicle begins to hydroplane, do not apply the brakes. Instead, slow down by releasing the accelerator and pushing in the clutch. This will help you to regain traction.

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2025 Iowa | Frequently Asked Questions

To secure a CDL Doubles/Triples endorsement in Iowa, you must first possess a valid Commercial Driver's License (CDL). Then, you need to pass the Doubles and Triples Endorsement Knowledge Test. This test covers the specifics of driving double and triple trailers, coupling and uncoupling, and inspecting doubles and triples. Remember, practice makes perfect.

To obtain a CDL Doubles/Triples license, you initially need a Commercial Driver's License (CDL). Then, you must pass the Doubles/Triples Endorsement Knowledge Test. The test covers topics like handling, coupling & uncoupling, and inspecting double and triple trailers. Studying the state's CDL manual and taking practice tests can help ensure success.

While Iowa doesn't specifically require specialized training to obtain a CDL Doubles/Triples endorsement, it's highly recommended. The endorsement requires passing a knowledge test on handling, inspecting, and coupling/uncoupling double and triple trailers. Studying the state's CDL manual and gaining practical experience through training programs can significantly improve your chances of passing the test.

Yes, to obtain a CDL Doubles/Triples endorsement, you are required to pass the Doubles/Triples endorsement knowledge test. This exam covers specific topics related to handling double and triple trailers, including coupling and uncoupling, inspecting doubles and triples, and pulling double/triple trailers. The test does not include a skills or driving test.

The CDL Doubles/Triples endorsement test is a written knowledge test, not a skills test, so you won't perform any driving maneuvers. The test covers information on handling, inspecting, and coupling/uncoupling double and triple trailers. It's important to have a good understanding of these areas to pass the written test. Practical skills are typically developed during on-the-job training after receiving the endorsement.

No, it's not permissible to operate double or triple trailers without a valid CDL Doubles/Triples endorsement in Iowa. This endorsement is required by federal and state law for any driver who intends to operate a vehicle towing two or three trailers. Driving without the proper endorsement can result in penalties, including fines and suspension of your commercial driving privileges.

You can add the CDL Doubles/Triples endorsement to your existing Commercial Driver's License. You don't need to initiate a new application for a CDL. However, you will need to pass the Doubles/Triples written knowledge test and pay any required fees to add the endorsement to your current CDL.

Yes, there are limitations for drivers with a CDL Doubles/Triples endorsement. One major constraint is the Gross Combination Weight Rating (GCWR) of 26,001 pounds or more, provided the GVWR of the vehicle(s) being towed is more than 10,000 pounds. Additionally, drivers must adhere to specific safety regulations related to coupling and uncoupling, inspecting, and driving double/triple trailers.

In Iowa, the maximum length for a double trailer is 81.5 feet. For triple trailers, it's 100 feet. The maximum weight for any vehicle or combination is 80,000 pounds gross weight depending on axle and bridge formula. However, specific weight limits can also be determined by the Federal Bridge Gross Weight Formula. Always check local and state laws for specific restrictions.

Yes, there are specific safety regulations for driving double/triple trailers. Drivers must adhere to guidelines concerning coupling and uncoupling, inspecting the trailers, and maintaining safe following distances. Other regulations include not driving in the left-most lane on interstates, obeying speed limits, and securing cargo properly. These regulations aim to ensure the safety of the driver and other road users.