In addition to safety protection functions, highway guardrails also have multiple functions such as separating the roadway from pedestrian areas, preventing vehicles from deviating from the lane, reducing collision injuries, providing guidance functions, marking dangerous areas, beautifying the urban environment, and diverting traffic flow. These functions together ensure the safety, orderliness, and aesthetics of highway traffic.

Highway guardrail is a belt shaped protective and energy absorbing structure installed on the outside or central divider of highway lanes. Its main purpose is to absorb collision energy, buffer and guide through blocking, guardrail deformation, or vehicle climbing in the event of an accident, thereby blocking the vehicle and reducing the degree of injury to drivers and passengers. According to the location of the cross-section of the road, highway guardrails can be divided into roadside guardrails and central median guardrails. According to the degree of deformation after being hit by a vehicle, it can be further divided into rigid guardrails, semi-rigid guardrails, and flexible guardrails.