A guardrail refers to a barrier on the side of a road or a bridge, constructed to prevent cars and other vehicles from veering off the roadway. Other synonyms for guardrail include safety fence, crash barrier, railing, and barrier. These terms describe the same protective structure and define its purpose: to keep motorists within the safety of their designated traffic lanes and prevent collisions with other vehicles or obstacles. A guardrail is primarily made of steel or concrete, but it can also be composed of wood, plastic, or other materials. These protective structures are essential to ensuring road safety and minimizing the risk of accidents and fatalities.