Median
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.
- Reduced head-on crashes.
- Can help to prevent dangerous overtaking manoeuvres.
- Can shift turning movements to safer locations.
- Can create space of protected turn lanes at intersections.
- Can create a refuge for pedestrians and bicyclists.
- Medians can restrict traffic flow if a vehicle breaks down, and can block access for emergency vehicles.
- Pedestrians are often reluctant to make wide detours, and so may attempt to cross at locations with barriers installed, resulting in dangerous pedestrian activity.
- In some regions the materials used in median barriers may be at risk of being stolen.
- The ends of median barriers must be well designed or they can be a safety hazard.
- Clearly visible signs and effective enforcement are needed to ensure that drivers do not drive on the wrong side of the median.
- Tall median barriers can adversely affect visibility when combined with curves and/or crest profiles.
- Continuous tall median barriers can contribute to tunnel vision of drivers and adversely affect the visibility and conspicuity of pedestrians crossings along the road.
The Star Rating Demonstrator is a freely available tool with the iRAP online software, ViDA. With the Star Rating Demonstrator, it is possible to explore the impact that this Safer Roads Treatment has on risk.
Treatment Summary
Costs | Medium to high |
Potential casualty reduction | 10 years - 20 years |
Effectiveness | 60% or more |
Case Studies
| Examples of related Case Studies |
|---|
| N-IV (CH. 558+500 – CH. 566+500, Seville) |
| Corridor C-12 Road |
| Mexico’s National Network |
| Rural road and motorway profiles |
