The transportation department's main objective in requiring the use of placards when transporting hazardous materials is to keep the public informed of the inherent dangers that come with the presence of hazardous materials. The placards are intended to keep hazardous materials properly segregated when transported on the same vehicle.
As part of its efforts to keep the public and shipping personnel aware of the presence of hazardous material, the transportation department requires that all containers used to ship hazardous materials be labeled with a diamond-shaped, 4-inch by 4-inch sticker that contains warning words and graphics. Similarly, the department requires that vehicles transporting hazardous materials use larger versions of the aforementioned stickers, in the form of a placard placed in plain view on the vehicle.
Placards are classified into several categories based on the type of danger the hazardous material poses. Some of these categories include explosive, flammable and corrosive.
