What does the wing wall transition section guardrail mean?

Guardrails are fences.

The wing wall is a retaining structure set up to ensure the stability of the roadbed slopes on both sides of the culvert or gravity abutment and to guide the river.

The wing wall is a retaining structure set up to ensure the stability of the roadbed slopes on both sides of the culvert or gravity abutment and to guide the river. There are two types of wing walls: straight wall type (perpendicular to the end wall) or splayed type (open and slanted). The latter, also known as the splayed wall, is the most commonly used form. The inclined angle is generally 30 degrees. The construction form of the wing wall is closely related to the topography, fill height and wiring.