Combination Vehicles · Question #146

Why should you check trailer tires more carefully on combinations?

A. Trailer tires are often older, worn, and more numerous
B. They are larger
C. They are heated
D. They are filled with nitrogen

Correct answer: A. Trailer tires are often older, worn, and more numerous
Explanation: Trailer tires often log many miles between visual checks.

Why this question matters on the Combination Vehicles exam

This question is one of the 65 we have for the Combination Vehicles CDL knowledge test. The official AAMVA Commercial Driver License Manual chapter on Combination Vehicles covers exactly this topic, and most state DMV exams pull from the same chapter. Memorizing the right answer is fine for passing, but understanding the underlying rule is what keeps you safe on the road and out of trouble with FMCSA inspectors.

If this topic gave you trouble, take the full Combination Vehicles practice test to drill it across all the related questions. We recommend reading every explanation, even on the questions you got right, because the manual phrasing in the explanation often shows up word-for-word on the real exam.

Take the full Combination Vehicles practice test →