Median barriers help prevent head-on crashes
Wire median barriers save lives. International studies show that up to 9 out of 10 people will survive a crash if they hit a median barrier. Wire median barriers are also narrow and suit New Zealand roads, so they are an excellent safety choice. Forty-six people have been seriously injured on the Hawke's Bay Expressway in the last 10 years. These barriers are a proven way for us to increase the safety of this road.
It’s hard to visualise as you drive alongside the wire median barriers how they actually work. They’re very powerful and quite ingenious. When a vehicle hits the barriers the high-tension wire cables flex, slowing down the vehicle and redirecting it away from the hazard (this could be an oncoming car, or if it’s the side of the road it could be a tree or a ditch for example).
This flexibility means that the barrier absorbs impact energy, reducing the force on the people in the vehicles, resulting in less severe injuries than other safety barrier systems and from collisions with roadside hazards or other vehicles.
Depending on the speed and angle of the impact a number of posts may bend over. This is how the posts are designed and does not lessen the safety benefits. Flexible road safety barriers are designed so they should not penetrate the passenger compartment of a vehicle, and the vehicle remains upright during and after a collision. They are also designed so that after impact the vehicle should not be deflected into an adjacent traffic lane.
During winter the NZ Transport Agency will be running a media campaign on median barriers and the safety improvements being installed on the Expressway. Look out for this on social media and share it with your friends.
*Johansson, R. (2009). Vision Zero – Implementing a Policy for Traffic Safety. Safety Science. 47(6), 826-831.