The Safe Systems Pyramid

Transportation safety is a public health issue ofincreasing importance as rates of traffic fatalities and serious injuries continue to rise. The Safe Systems Pyramid presented in this policy brief is a tool that incorporates public health principles to evaluate transportation safety policies and interventions. The Safe Systems Pyramid can help transportation practitioners and decision-makers prioritize projects for safety and communicate priorities to the public. For decades, the traditional “Es” framework of transportation safety has implied equal weight between engineering, enforcement, and education interventions. Because these interventions are not equally effective, the Es paradigm neglects public health principles, which prioritize population-level interventions that require less individual effort and focus on the pathologic agent—in this case, the transfer of kinetic energy. The Safe Systems Pyramid combines two models for these principles: the Health Impact Pyramid prioritizes interventions that have increasing population health impact and decreasing individual effort; and the Hierarchy of Controls, used in occupational safety, organizes strategies by effectiveness.