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Iowa Combination Vehicles CDL Practice Test

Free Combination Vehicles practice questions tailored for Iowa CDL applicants. The questions follow FMCSA standards used by the Iowa Department of Transportation.

Why this matters in Iowa

Iowa DOT administers all CDL knowledge tests on touchscreen kiosks at driver license service centers. If you are pursuing the Combination Vehicles portion of the Iowa CDL exam, the Iowa Department of Transportation will use the same federal core questions you practice here, plus any state-specific items the Iowa Department of Transportation chooses to include.

What you will learn

The Combination Vehicles test covers driving tractor-trailers and other combinations with a Gross Vehicle Weight Rating over 26,001 pounds where the towed unit exceeds 10,000 pounds. Topics include coupling and uncoupling, fifth wheel inspection, off-tracking, rearward amplification, jackknife prevention, rollover, antilock brake systems, and emergency procedures specific to articulated vehicles.

Sample questions

• Q1. A combination vehicle is generally defined as:
• Q2. The 'fifth wheel' on a tractor is:
• Q3. The kingpin is part of the:
• Q4. When coupling, you should approach the trailer:
• Q5. After backing under the trailer, you should:
• Q6. Visual inspection of the fifth wheel coupling must confirm:
• Q7. The trailer's landing gear should be:
• Q8. When uncoupling, after lowering the landing gear and disconnecting glad hands you should:
• Q9. The coupling height check before backing under the trailer is critical because:
• Q10. A high-coupled trailer (kingpin riding above the jaws) can result in:
• Q11. Off-tracking by the trailer means:
• Q12. Rearward amplification means:
• Q13. A trailer jackknife is:
• Q14. The first sign of a tractor drive-wheel skid is often:
• Q15. To prevent rollover with a high center of gravity, you should:
• Q16. A loaded trailer with a high center of gravity is most prone to roll over:
• Q17. Cargo loaded too far to one side will:
• Q18. Cargo loaded too far forward can:
• Q19. Cargo loaded too far rearward can:
• Q20. When checking trailer brakes via the hand valve, you should:
• Q21. The fifth wheel should be greased:
• Q22. Air lines and electrical cables between tractor and trailer must be:
• Q23. When backing a trailer, the trailer initially turns:
• Q24. When backing into a tight spot, you should:
• Q25. The 'safety latch' on the fifth wheel locking lever:

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Iowa test logistics

The Iowa Department of Transportation charges a permit fee of $25 and a license fee of $8/year. The minimum age is 18 (intrastate) / 21 (interstate). Schedule your knowledge test through the Iowa Department of Transportation once you can score above 90% on this site's practice bank.