Life-wire: Barriers may save life a week
They cost $2 million a kilometre to install but wire rope barriers are believed to save at least one life a week.
The barriers have proliferated along road berms and centre-lines around the country over the past decade, and a lot more are coming.
The New Zealand Transport Agency is a big fan of the wire ropes, which have proved to be an affordable and effective way of saving lives.
NZTA’s acting director of safety and environment, Lisa Rossiter, said the transport agency did not keep track of the number of times the ropes had saved lives but it received at least one report a week of one being hit in a manner that would most likely have saved a life.
‘‘A barrier strike where we have to replace posts or wires means someone wasn’t killed or seriously injured. They’re put in places where you’d be highly likely to die if it wasn’t there,’’ she said.
Detail on the location of all wire barriers was not immediately available, but Rossiter listed the highest-profile ones as those on Centennial Highway near Paeka¯ ka¯ riki; State Highway 58 between Upper Hutt and Plimmerton; on SH2 River Rd in Upper Hutt; Eastern Hutt Road in Lower Hutt; SH6 Nelson to Richmond; SH3 Hamilton to Ohaupo; SH1 Rangiriri in Waikato; SH1 Northern Brynderwyns in Northland; and the Tauranga Eastern Link.
Since the wire ropes were installed on Centennial Highway in 2009, there hasn’t been a single death or serious injury from a head-on crash.
The wires were once hotly opposed by some motorcyclists, who called them ‘‘cheesecutters’’ for the sort of injuries they would inflict on motorcyclists who ran into one.
Opposition had died down considerably, largely in the face of studies that showed how effective they were and how few motorcyclists hit them, but there were still a few people who didn’t like them.
Rossiter said it cost about $2 million per kilometre to install a wire rope barrier. Typically made of three or four tensioned wire cables supported by steel posts, they deflect and absorb the energy of an impacting object and their posts collapse. They are used on road edges or as median barriers.
They are the cheapest barriers but the most expensive to maintain, as even lowimpact crashes can result in damage. ‘‘It’s a tiny cost compared to the benefits.’’
The latest average social cost of a fatal crash was estimated at $4,916,000. It was $923,000 for every reported serious injury crash and $104,000 per reported minor injury crash.
‘‘They’re the difference between life and death. It’s profound the difference they have, from the moment they’re installed,’’ Rossiter said.
There would definitely be plenty more wire ropes installed around the country.