Medians physically separate opposing traffic streams and help stop vehicles travelling into opposing traffic lanes.

They are often built on the centre of wide urban multi-lane and high-speed roads and can be used to limit turning options for vehicles and shift these movements to safer locations, create space for protected turn lanes at intersections, and provide a refuge for pedestrians and bicyclists. Medians can also be accompanied by pedestrian fencing or safety barriers.

Median safety barriers can be made of a range of materials including concrete, steel, and wire rope. Decisions about what type of median barrier should be used should be based on several factors including traffic volume, traffic speed, vehicle mix, median width, the number of lanes, road alignment, crash history, and installation and maintenance costs.