Layer of Structures (road and pedestrian bridges, rail bridges, sign gantries and tunnels), in Western Australia. This layer provides general inventory information for all Structures on State roads, Local roads or Department of Environment and Conservation (DEC) roads. A road structure is that portion of the carriageway that carries vehicular, pedestrian, and bicycle traffic over or under an obstruction such as a watercourse, another road or railway line. This layer shows the location of Structures on all public access roads in Western Australia and is provided for information only.