When loading a vehicle with hazardous materials, you should:
Correct. Set the parking brake, chock wheels of cargo tank vehicles, and shut off the engine before loading or unloading flammables.
CDL Practice Question #243
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.