How are placards selected for a vehicle carrying multiple hazmat goods?

• A. Use placards for the highest hazard class present
• B. Place placards on all four sides
• C. Follow 172.504
• D. Determine the highest hazard class present and apply corresponding placards; follow 172.504 for placement on all four sides

Answer: (D)

When a vehicle carries multiple hazmat goods, you signal the most dangerous hazard on board. Identify the highest hazard class present and apply the placard that corresponds to that class. Then follow the placement rules in 172.504, which require placards to be displayed on all four sides of the vehicle so the warning is visible from any angle. This approach ensures responders know the worst possible hazard they might encounter, even if multiple hazmat classes are on board. The other options miss either the necessity to use the most dangerous class placard or the requirement to place placards on all four sides, so this combination best matches how placards are used for mixed hazmat loads.