Are placards required for all hazardous material loads?

Placards are an essential safety measure for transporting hazardous materials, but they are not universally required for all hazardous materials. The requirement for placarding depends on the specific type and quantity of the hazardous material being transported. For instance, the U.S. Department of Transportation (DOT) mandates that placards must be displayed on vehicles transporting certain quantities of hazardous materials that meet specific criteria outlined in the Hazardous Materials Regulations (HMR).

Certain materials may not meet the thresholds set forth, meaning a vehicle carrying these substances would not require placards. Moreover, some materials may be exempt or might require specific labeling or markings instead of full placarding, depending on the regulations. Therefore, only some hazardous materials necessitate placarding, which aligns with the chosen answer. Understanding these criteria is crucial for compliance and safety in the transportation of hazardous materials.