A pedestrian separation structure is any structure that removes pedestrians from a roadway, street or railway track. This creates a road junction where vehicles and pedestrians do not interact.
This can be considered a type of grade separation structure on the road.
These structures can be located either above the roadway or below the roadway. In the U.S., access under the Americans with Disabilities Act requirements means that stairs cannot be the only access to these structures. An elevator must be provided or a ramp built that conforms to the grade requirements under the ADA regulations.
In the broadest sense, building codes that limit the number of driveways that cross sidewalks may be viewed as making the sidewalks a separation structure.
In many areas, wildlife crossings are provided in wilderness areas to allow wildlife to cross roadways without risking accidents. While not specifically built for people, they could be used by people in those areas.