When transporting hazmat, you must check the cargo every:
Correct. Federal cargo securement: check at the start, then every 150 miles or 3 hours of driving, plus every change of duty status.
CDL Practice Question #268
Category: Hazmat
Why this question matters
This question is one of 68 in our Hazmat bank. The reasoning above comes directly from the AAMVA CDL Manual, the source document used by every U.S. state DMV. Memorizing the underlying rule — not just the letter answer — is what separates passing on the first attempt from a return trip and another fee.