Where must hazardous materials placards be displayed on a transport vehicle?

Hazmat PLACARDS must be displayed on ALL FOUR SIDES of the vehicle — front, rear, and both sides — so the hazard is visible from ANY direction. CDL hazmat. This ensures emergency responders, other drivers, and the public can identify the hazard regardless of which side of the vehicle they approach. Placards must be: readable (right-side up, not faded/obscured), securely attached, kept clean and visible, and removed when no longer carrying the hazmat (or when the vehicle is empty/cleaned, per rules). The correct placard corresponds to the material's hazard class. Placement on all four sides is a specific, commonly tested placarding requirement. Knowing placards go on all four sides is fundamental hazmat knowledge.