Guardrail supports are installed on both sides of the road to prevent unauthorized entry by pedestrians and other vehicles, reducing the destructive impact and allowing out-of-control vehicles to change direction.

Restore original driving direction, prevent falling under the bridge, guardrails can be divided into rigid guardrails and flexible guardrails; collision barriers are also a necessity for highways.

Facilities can impact both the safety, comfort of high-speed operations, and the cost of construction.