What does a higher number display on a radioactive materials placard indicate?

A higher number displayed on a radioactive materials placard indicates a higher radiation emission level associated with the material. The numbers on these placards correspond to the categorization of radioactive substances, with larger numbers representing greater levels of hazard due to increased radiation activity.

This system is designed to inform emergency responders and the public of the potential risks involved in handling or being in proximity to the material. A lower number would signify a lesser degree of risk and radiation emission. The emphasis on higher numbers correlating to increased radiation helps in assessing necessary precautions and ensuring safety during the handling and transport of radioactive materials.

The other options do not specifically link to the numerical representation used on placards: increased safety measures, lower risk level, and more stringent packaging requirements may pertain to general safety protocols but are not directly correlated to the numerical classification indicated on the placards.