A trailer's placard shows the correct hazard class and is mounted in the correct position, but a ladder bolted to the trailer partially covers its lower corner. Is this placard compliant?

49 CFR 172.516(c)(2) (placards must be located clear of appurtenances and devices such as ladders, pipes, doors, and tarpaulins); AAMVA CDL Manual Sec. 9.3.10 (nhcdm.pdf p.9-8)

Inspectors check not just whether the right placard exists, but whether it's actually visible and legible from each direction. A technically-present but obstructed placard can still result in an out-of-service order or citation.