Are wire rope barriers – barriers to oversize?


Wire rope median barriers have an excellent record for reducing head-on accidents in black-spot areas, however the requirements for other road users – including the oversize industry – must be taken into account when planning for them.

The past few years have seen the rise and rise of retro-fitted wire rope median barriers – particularly as part of the NZTA’s $600m Safe Roads project. This association has been engaged with this project from the start, but the sheer number of projects that are being considered means that it is difficult to attend all the meetings and stay in touch with the different stages of each.

Then add to that the recent revelation on The Nation TV programme that NZTA has a project to add up to 980 kilometres of median barriers to the nation’s State Highways.

Much of this appears to be driven by the Associate Minister of Transport, Julie Anne Genter, who is on record as saying “The Government has proposed a significant boost in funding to improve local and regional roads right around the country. This will have a particular focus on proven safety treatments, like median and side barriers.”

Don’t get me wrong, median barriers are an effective tool to improve the safety of road users where there are accident-prone areas and we support the installation of median barriers where necessary to prevent fatalities and major injury accidents. However, we are concerned the planning of these installations has to take into account the width and clearance requirements of the overdimension transport industry. Otherwise the median barrier solution to eliminate fatalities may well create new risks.

Where centre barriers are installed thought needs to be given as to the positioning of roadside signage, light poles and trees to ensure particularly wide loads do not have difficulty manoeuvring around them, placing a significant portion of the load in the opposing lane for traffic on the other side of the barrier. This is particularly the case where centre barriers are installed on roads with a single lane in each direction.

Motorists travelling on roads divided by a centre barrier do so with a degree of comfort that oncoming traffic on the other side of the barrier cannot affect them. While overdimension loads are required to have pilots to warn oncoming motorists of the overdimension load hazard, it can be difficult to attract the attention of some motorists in this situation.

It is of great concern to the oversize industry that a major NZTA project to install nearly 1000 kilometres of wire rope barrier is to be finalised soon, but there appears to have been very little visibility of it.

At least with the Safe Roads projects, NZTA seeks input from local residents, road users and other parties about what safety issues there are, and the ways to mitigate that risk that is going to work for all stakeholders.

It is not just the oversize transport industry that has issues with the design of these barriers. A median barrier can also prevent emergency services from accessing an accident site, and traffic that is built up behind an accident on a road with single lane in each direction will cause major issues.

Other problems with these barriers are where they are installed on the side of the road, then the shoulders are no longer accessible for road maintenance vehicles to pull off, without major traffic management, when large vehicles break down there is often not a lot of space to pull over, and there are even scenarios where school buses no longer have space to pull off the road to let their passengers off due to road side barriers.

Finally, people that live adjacent to these barriers only have the option to turn left out of their front gate and then undertake a u-turn at the next gap in the barrier if they want to travel in the opposite direction.

The oversize industry is seeing greater and greater demand for overdimension loads – particularly pre-fabricated units to be transported from the manufacturer to site. Part of the Government’s KiwiBuild programme for new houses appears to rely on new transportable houses constructed in a manufacturing facility and then shifted by transporter to the final residential site.

If the transport of these oversize loads is to be undertaken safely, then more thought needs to go into the planning of any new median barriers, so as to identify and remove any roadside barriers, and if this can incorporate road widening at the same time, then this would be hugely beneficial.

The Association has written to the Minister concerned and the NZTA about the Wire Rope Median project seeking engagement with this project.

We are calling for a careful analysis of the locations, the overall road width, and the identification of roadside width restrictions before any further wire rope barriers are approved.

If this means targeting specific and shorter pieces of accident-prone areas with a greater investment in road widening and roadside restriction removal, then we would support this.

It is of great concern to the oversize industry that a major NZTA project to install nearly 1000 kilometres of wire rope barrier is to be finalised soon, but there appears to have been very little visibility of it.

Related posts

Parting words from Jeremy Sole- a final column

Contrafed PUblishing

Smoko antics

Contrafed PUblishing

John Deere K-Series wheel loaders

Contrafed PUblishing