Iowa CDL General Knowledge Test (IA) 5

4.9 out of 5 (45 votes)
80% Passing score
50 Questions
10 Mistakes allowed
As an Iowan gearing up for the CDL written knowledge test, you know that thorough preparation is key. Here, we offer the fifth in our series of Iowa CDL General Knowledge Practice Tests, designed to help you build confidence and expertise for the big day. Our practice test features 50 questions, mirroring the structure of the actual DMV permit test. To pass, you must correctly answer at least 40 questions, a standard that ensures you're well-prepared. Unlike many resources that charge a fee, our Iowa CDL practice test is completely free. We believe in providing quality study tools without the price tag. This means you get to enjoy the same level of features and opportunities for learning as you would with a paid version, but without any cost. Our CDL practice test is meticulously crafted to reflect the format of the actual Iowa CDL general knowledge test. Expect a mix of multiple-choice and true or false questions, which will train you in the art of eliminating incorrect answers to pinpoint the right one. This format is not just about testing your knowledge, but also about honing your test-taking skills, an essential part of acing the general knowledge test. One of the standout features of our DMV practice test is the end-of-test summary. This valuable feedback provides a rundown of your performance, highlighting any questions you might have missed and providing the correct answers. It's a fantastic way for you to learn from your mistakes and solidify your understanding of the test material. Remember, you can take this Iowa CDL general knowledge test as many times as you need. The questions will remain the same each time, allowing you to track your progress and focus on areas where you need more practice. It's more than just a test; it's a comprehensive learning tool designed to support you every step of the way as you prepare for your Iowa CDL general knowledge test in 2026.
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Sample Iowa CDL Test Questions - General Knowledge

Question 1

Which statement describes proper speed management?

  1. A An empty truck always stops sooner than a loaded truck
  2. B Doubling speed only doubles stopping distance
  3. C Drive at a speed that permits stopping within the visible distance ahead
  4. D An alert driver may safely follow another vehicle closely

Correct answer: C – Drive at a speed that permits stopping within the visible distance ahead

A commercial driver should be able to stop within the distance visible ahead. Rain, fog, darkness, curves, and other conditions can reduce sight distance and require a lower speed. Doubling speed can increase braking distance by about four times, and empty heavy vehicles may require more stopping distance because they have less traction.

Source: Iowa Commercial Driver’s License Manual — §§ 2.6.1, 2.6.4, “Speed and Stopping Distance; Speed and Distance Ahead”

Question 2

If you become drowsy while driving, which response is appropriate?

  1. A Stop in a safe place and sleep
  2. B Take a short nap if you cannot stop for the night
  3. C Do not use drugs as a substitute for sleep
  4. D All of the above

Correct answer: D – All of the above

Warning signs of fatigue require the driver to stop driving and rest. The manual recommends sleeping for the night or taking a short nap in a safe location. Drugs may keep someone awake temporarily, but they do not restore alertness. Medications that cause drowsiness should also be avoided before driving.

Source: Iowa Commercial Driver’s License Manual — § 2.11.2, “Driver Factors—Fatigue and Lack of Alertness”

Question 3

An orange traffic sign most commonly identifies:

  1. A Temporary traffic control, such as construction or maintenance work
  2. B A general permanent warning
  3. C Destination or route guidance
  4. D A requirement to stop

Correct answer: A – Temporary traffic control, such as construction or maintenance work

Iowa’s traffic-control-device rule adopts the MUTCD for signs used on roads open to public travel. Orange signs are used for temporary traffic control, including construction and maintenance operations. Yellow is generally used for permanent warning signs, green commonly provides directional guidance, and red communicates stopping or prohibition.

Source: Iowa Admin. Code r. 761—130.1 – Manual, Manual on Uniform Traffic Control Devices, 11th Edition — Ch. 6F, “Temporary Traffic Control Zone Signs—General”

Question 4

On an Iowa multilane roadway, what does a SLOWER TRAFFIC KEEP RIGHT sign direct a slower vehicle to do?

This sign indicates that drivers ___________.
  1. A Use the right-hand lane unless passing or preparing for a left turn
  2. B Remain in its current lane at all times
  3. C Pass other vehicles on the right
  4. D Increase speed until it matches every other vehicle

Correct answer: A – Use the right-hand lane unless passing or preparing for a left turn

A vehicle traveling below the normal speed of traffic must use the available right-hand lane or stay as close as practicable to the right edge. Exceptions apply when the vehicle is overtaking another vehicle or preparing for a left turn. The sign reinforces this lane-use requirement; it does not direct drivers to exceed a safe or lawful speed.

Source: Iowa Code § 321.297(2) – Driving on right-hand side of roadway—exceptions

Question 5

When fighting a vehicle fire with an extinguisher, should you aim above the base and into the upper flames?

  1. A True
  2. B False

Correct answer: B – False

Aim the extinguisher at the source or base of the fire, not at the upper flames. Directing the extinguishing agent at the base helps it reach the burning material. Position yourself upwind when possible, and continue until the material has cooled because a fire can restart even after visible flames and smoke disappear.

Source: Iowa Commercial Driver’s License Manual — § 2.21.3, “Fire Fighting—Extinguish the Fire”

Question 6

When operating a fire extinguisher, should you stand as close to the fire as possible?

  1. A Yes
  2. B No

Correct answer: B – No

The manual directs drivers to stay as far from the fire as possible while using the extinguisher. Position yourself upwind and aim at the source or base of the fire. If you are unsure which extinguishing agent is appropriate, particularly with hazardous materials, wait for trained firefighters rather than taking an unnecessary risk.

Source: Iowa Commercial Driver’s License Manual — § 2.21.3, “Fire Fighting—Extinguish the Fire”

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