What is the primary purpose of hazardous-material placards?
Correct answer: A – To warn others about the hazardous materials being transported
Placards warn other road users, inspectors, and emergency responders that hazardous materials are being transported. Their colors, symbols, and identification information communicate the cargo’s hazard class or specific hazard. Federal hazardous-materials regulations require applicable placards to be displayed on each side and each end of a transport vehicle or freight container as prescribed.
Source: Connecticut Commercial Driver’s License Manual — § 9.3.3, “Lists of Regulated Products—Placards”, 49 CFR § 172.504 — General placarding requirements

