An emergency room doctor says head-on crashes on high-risk roads could be eliminated for less than the cost of a new motorway.
Transport Ministry documents show it would cost between $550 million and $1.1 billion to install wire rope median barriers on the 372 kilometres of road that carry more than 12,000 vehicles a day.
Between 2006 and 2009, there were 26 fatalities and 75 serious crashes from crossing the centre line.
The director of the Kapiti Emergency Medical Service, Chris Lane, says that where wire rope has been installed - such as the section of State Highway 1 between Pukerua Bay and Paekakariki - it has been a success.
"There hasn't been a single accident causing any major medical injury along that stretch at all," Dr Lane says. "It just stopped overnight. And the barrier itself has been hit over 80 times."