Final answer:
A placarded vehicle must have at least four placards.
Step-by-step explanation:
A placarded vehicle must have at least four placards.
In the United States, the Department of Transportation (DOT) requires vehicles carrying certain types and quantities of hazardous materials to display placards on all four sides.
The placards serve to indicate the specific types of hazardous materials being transported, such as explosives, flammable liquids, or corrosive substances.