Function of the GuardrailGuardrails function as a system, which includes the guardrail itself, the posts, the soil that the posts are driven in, the connection of the guardrail to the posts, the end terminal, and the anchoring system at the end terminal. All these elements have a bearing in how the guardrail will function upon impact. To simplify, a guardrail consists of two key functional components: the end terminal and the guardrail face.

The Guardrail Face. The face is the length of the guardrail extending from the end terminal alongside the road. Its function is always to redirect the vehicle back onto the roadway. The End Terminal. The starting point of the guardrail is referred to as the end treatment. The exposed end of the guardrail needs to be treated. One common treatment is an energy-absorbing end treatment that is designed to absorb the energy of an impact by having the impact head slide down the length of the guardrail. These end terminals function in two ways. When hit head-on, the impact head slides down the guardrail flattening, or extruding, the guardrail and redirecting the guardrail away from the vehicle until the vehicle’s impact energy is dissipated and the vehicle has decelerated to a stop.