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  • Updated for December 2024
  • Based on 2024 IA commercial driver's license manual

Free IA CDL Diagnostic Test 2024

To get a rough idea of how much you know about commercial driving rules in Iowa, try our IA CDL diagnostic test. It contains 30 multiple-choice questions on a variety of topics in commercial driving: air brakes, hazardous materials, buses, combination vehicles, and tanker trucks. This test will help you quickly identify gaps in your knowledge of commercial driving, which will be especially useful if you’re just starting to prepare for the CDL knowledge exams. Each practice question includes a picture and has four possible answers. Choose the most complete and correct answer for each question. Each question also comes with an optional hint if you need it and an explanation of the correct answer. Try our CDL diagnostic test and see whether you are ready for the real thing. Good luck, and drive safely!

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  • Perfect for first-time and renewal CDL/CLP applicants, and those adding endorsements

What you need to know

4.5 out of 5 • 4 votes
5 min to complete
Available in EN and ES
Verified by Steven Litvintchouk, M.S., Chief Educational Researcher, Member of ACES. See our detailed commitment to accuracy and quality in our practice tests.

What to expect on the actual IA DOT exam

50

questions

40

correct answers to pass

80%

passing score

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Experience the Driving-Tests difference
Since our foundation in 2010, Driving-Tests.org has led the way in online driver's education, with over a decade of experience. Our dedicated experts, bringing together more than 50 years of collective expertise, have established us as the largest non-governmental organization in the U.S. solely focused on driver education. We go beyond the official manuals, offering unique interactive experiences and support like audio guides and an AI Assistant, to cater to different learning styles and needs.
Helping hundreds of thousands to ace their tests, our resources have earned a 4.7-star rating from over 14,500 reviews. Our goal is to make your path to becoming a confident driver as straightforward and effective as possible.
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