Free Iowa CDL Double/Triple Trailers Practice Test 2023

Do you know how to pair double or triple trailers? If you are planning to take the CDL double/triple trailer endorsement test, make sure to know it! Our Iowa CDL Practice Test has the same questions as the real exam which is based on the Iowa CDL Manual. It covers most of the subject areas on the Double/Triple Trailers Test such as pulling double and triple trailers, the risk of rollover, managing space, and special considerations when hauling multiple trailers. In addition, each question has a detailed explanation that will help you understand the concept and answer future questions about it correctly. If you don't get the pass right away, you can take this CDL practice test an unlimited number of times to make sure you learn all the questions. Let’s try our Free Iowa CDL Double/Triple Trailers Practice Test today and pass your CDL endorsement exam! Good luck and keep driving safely!

Our CDL practice tests:
Based on 2021 IA commercial driver's license manual
Full answers + detailed explanations
Perfect for first-time, renewal applicants
IA CDL Double/Triple Trailers Test format:
20 questions
16 correct answers to pass
80% passing score
List of questions
What is the purpose of a modulating control valve?
What is the "cut-in" pressure for most air compressor governors?
The air compressor governor stops air from pumping when it reaches the "cut-out" level or around generally _________.
To test the tractor protection valve, the engine needs to be:
If air supply drops when driving, the tractor protection valve ________.
When connecting converter dolly to the front trailer, support gear should be:
You should check trailer height before connecting a converted dolly to a second or third trailer. The trailer height is right when:
Brake linings should not be _______.
When coupling or uncoupling, trailer or dolly wheel should always be:
If the rear trailer does not have spring brakes, disconnecting the emergency line after charging will:
Air tanks need to be drained ______.
What is likely to happen if the pintle hook is unlocked with the dolly still under the second trailer?
Before you can supply air to the air tanks of a second trailer you need to:
When the safety valve releases air this indicates ___________.
Why does a heavily-loaded vehicle take longer to stop than a lightly-loaded vehicle?
A safe speed on a curve for a smaller commercial vehicle:
Water and oil _______.
In dual-air systems the pressure should build to _______.
Why should you not drive your vehicle if the air pressure does not build up quickly enough?
Vehicles with air brakes have pressure gauges connected to the _______.