This median barrier has prevented more than 150 serious incidents from occurring on our State Highway. Photo: Charles Anderson.

Lifesaving barrier’s true cost revealed


The median barrier that stretches along Whakatu Dr on SH6 has potentially saved dozens of lives and millions of dollars as new data reveals the interventions it has made in preventing head-on collisions in Nelson.

The wire rope barrier was installed in 2006, at a cost of about $5 million.

Since then, it has been hit an average of 12 times a year, with an average repair cost of $5,000 each time, data released by Waka Kotahi NZ Transport Agency shows.

However, there have only been 10 incidents of serious injury in the time since it was installed.

“I think of median barriers as vaccines for roads,” says Waka Kotahi NZ Transport Agency’s senior road safety manager Fabian Marsh.

“Where they exist, people don’t notice them but when something goes wrong, they can be life or death.”

In the last 20 years there has only been one death on the highway, relating to an incident where a crash occurred in the area of where the wire barrier now is. That incident occurred in 2002.

The transport agency says that a death on our roads will cost society about $4.5 million while a serious injury will cost about $500,000.

This means that the barrier has long since paid for itself in terms of societal economic impact.

If all those incidents requiring a repair of the barrier had been serious injuries instead, it would add up to $84 million, or $756 million if they had resulted in death.

A map of where the serious incidents have occurred along the stretch of road since 2006. Photo: NZTA.
A map of where the serious incidents have occurred along the stretch of
road since 2006. Photo: NZTA.

Fabian says head-on crashes account for about half of all deaths on State Highways and median barriers are a proven lifesaving device, that provide separation of traffic and virtually eliminate high speed head-on crashes.

“A momentary lapse of concentration is all it might take to cross into the path of an oncoming vehicle and end in tragedy.”

The median barrier absorbs the energy of the crash, rather than doing damage to the vehicle, Fabian says.

“Often vehicles drive off after crashing.”

While there was a fatal crash on Whakatu Drive in early 2019, which killed two people, that accident was not related to the median barrier.

The agency’s goal is called ‘Vision Zero’ and represents a New Zealand where no one is killed or seriously injured in road crashes.

The target is to reduce death and serious injuries on our roads by 40 per cent over the next decade.

Steady progress towards this would mean around 750 fewer people would be killed on our roads over the next 10 years, compared to 2018.