To decide which placards you need, if any, what three things do you need to know?
1) Materials hazard class, amount being shipped, and amount of all hazardous materials of all classes on your vehicle
2) Packing group numbers, amount being shipped, and amount of all hazardous materials of all classes on your vehicle
3) Materials hazard class, percentage of total volume, and amount of all hazardous materials on your vehicle
4) Materials hazard class, location being shipped, and amount of all hazardous materials on your vehicle