Social networks may be among the ways the New Zealand Transport Agency informs motorists of road closures in future.

Brett Gliddon, NZTA's Bay of Plenty State Highways Manager says remotely operated roadside signs, informing radio stations and news websites are already used but social media such as Twitter might be another option to help reduce frustrations for motorists caught in traffic jams.

Brett says the aim is always to re-open roads quickly but that's not always possible, especially in crashes causing death.

In such cases control of the section of road is in the hands of police, who carry out forensic investigations to establish the cause of the crash if charges are to be laid or for a coroner's inquest.

'A lot of work has been done to get road closure times down. Five to 10 years ago roads could be closed for hours on end but we now have a memorandum of understanding with police to get roads open as soon as possible. The aim is one and a half hours but that's not always possible.” Closing rural highways because of slips, floods or crashes can cost tens of thousands of dollars in economic losses, as well as cause major disruptions for drivers, especially when easy detours are not available.

A Lincoln University study carried out in the Kaikora district in 2000 showed the 'potential' cost of road network disruption for road-users and non-users exceeded $250,000 per day. Twelve years on, and for North Island roads, the figure is likely to be significantly more.

In the case of crashes causing injury or death, there's also significant costs. The Ministry of Transport estimates the social cost of road injuries is approximately $3.8 billion per annum. Social cost includes the cost of the loss of life and life quality, loss of output due to temporary incapacitation, medical costs, legal costs and property damage costs.

On November 12, State Highway 2 just north of Katikati was closed for four hours after an 18-year-old Huntly man James Dean Miles, died in a head on crash. Traffic backed up for kilometres on both side of the accident scene, with the only alternate route north or south, over the Kaimai Ranges. Among those caught in traffic was Katikati beautician Jo McLachlan who waited in line for 45 minutes before she discovered how long the delay would be.'We were moving slowly and I could see traffic coming towards me so thought some vehicles were being let through. Then I realised it was vehicles leaving the queue and turning back.

'I finally drove alongside a policeman who said there would be a three to five hour delay, so I went to a friend's home to wait. We kept checking the NZTA website but it said the road was closed until further notice. Finally around 9pm we could see the lights of cars moving along the highway so I guessed the road was open and headed for home.”

Brett says a more definitive time wasn't given on the website because the authority didn't know when the road would re-open, because police were in control of the crash site.

Roadside signs just north of Tauranga and south of Pearoa had been remotely activated, warning that the road was closed, as were signs on the Auckland and Waikato motorways.

The Joint Traffic Centre in Auckland controls those signs and also informs radio stations and news websites.

For up to date road closures check www.sunlive.co.nz