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Case Study: The Coast Road Median Barrier
- Wellington, New Zealand


In the seven years from 1994 to 2000 there were 21 head-on crashes on the Coast Road section of State Highway 1 north of Wellington. Transit New Zealand responded with a series of control measures that successfully eliminated fatal crashes for two years.

Then in 2004 the incidence of two serious crashes reignited the community’s call for further action. Transit responded quickly,tackling the challenging physical environment to install a 700 metre long median barrier on the narrow carriageway.

Physical works on the median barrier began on 26 October 2004. On 22 November, the NZ$1 million project was completed. In total, from planning through to completion, the Coast Road median project took little more than three months. Following the outstanding success of the median barrier, it was extended in length to 3.4 kilometres in 2007.

Safety Improvements

Crash records for the total 3.4 kilometre length over the five year period prior to the initial median barrier installation (between 2000 and 2004) indicate that there were 7 fatal crashes, 3 serious injury crashes, 5 minor injury crashes and 17 non-injury crashes.

Over the following five year period from 2005 to 2009 there was 1 serious injury crash, 4 minor injury crashes and 33 non-injury crashes. The serious injury crash in the last five year period happened in 2008 and involved a cyclist that was hit from behind by a car.

Transit also installed video cameras to monitor driver behaviour before, during and after installation of the barrier. Since the initial installation of the barrier, there had 59 recorded strikes on the barrier as of January 2010.

Driver behaviour and confidence has improved. The surveillance footage showed drivers are positioning themselves more centrally in the lane, giving more separation between opposing vehicles.

More information

Transit New Zealand prepared a detailed overview of the initial project, which can be downloaded from the ‘References’ box to the right. The overview describes how an innovative approach was used to manage very challenging terrain and key social, economic, cultural and environmental benefits.

This case study was provided by the New Zealand Transport Agency.

References: Centennial Highway Safe System Case Study – Transit New Zealand (2005) Tackling high risk roads through innovation – The Coast Road median barrier project.