Placards must be displayed on each side and each end of a large means of containment.
They may be displayed on a frame that is permanently connected to the large means of
containment. The placard may also be placed at the front of a truck instead of on the
leading end of a trailer unit of the truck. The placards must be visible from all four sides of
a large means of containment, or moved to an appropriate position where they are visible.