Steel wire safety fences: should they be on UK roads?

Blue Systems SAFENCE pic

Published on 20 January 2016 by Gill

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Filed under categories: Features, Campaigning

Graeme Hay examines the issue of rope wire safety fences

It is no surprise that all motorcyclists are concerned and fearful of steel safety fences, both on central reserves and on the verges of roads. You really do not have to look at a steel fence for very long to see why; it’s the posts that support the barrier.

Many motorcycle collisions result in a slide along the surface of the road, either before or after a collision. In some cases, the event begins and also ends with an impact. This is the reason that so much research and effort has been put into development of the helmets, clothing and body armour that resists or absorbs the energy associated with slides or impacts. It is with this in mind, no doubt, that many motorcyclists regularly choose to spend many hundreds of pounds to buy and wear this equipment to protect themselves from slides and impacts.

Research by the AA Foundation a decade or so ago looked at the risks for all road users presented by road-side trees, street furniture and walls, and made a number of recommendations to guide roads authorities in a field which was to become known as ‘Passive safety’. In many areas of the country, steel sign posts are being replaced with either foam-wrapped steel posts, extruded aluminium lattice posts or simply removed. The Highways Agency has actively removed many trees from within 4.5 meters of the road’s edge, where possible.

Wire Rope safety fenceThese measures go hand-in-hand with a long-standing balanced approach to introducing steel safety fences only at locations where there is a significant risk from a roadside slope, structure or (in the case of a central reserve) a head-on collision in the UK.

In Germany, many more roads than in the UK have been equipped with steel barriers in woodland areas. Allgemeiner Deutscher Automobil-Club e.V (ADAC), an organisation very similar to the AA, has done research into the usage of steel safety fences on verges, where the proximity of trees has obliged engineers to install barriers under state highways guidance.

The ADAC research points very clearly to the removal of many barriers in these sort of locations and their replacement with sloping earth banks to retain vehicles and remove the risk to motorcyclists.

In some other countries, including Sweden, steel safety fences were seen as a solution to almost every type of collision on rural routes and they have been used in many situations that no road engineer in the UK would ever consider appropriate. A result of the Swedish approach is that, in the early part of 2014, safety fences featured in six of the 22 fatal motorcycle collisions where no other vehicle was involved.

In the UK on a central reserve of less than 20 or more metres wide, which are far and away the most common, it is completely true that the greatest collision risk to a motorcyclist comes primarily from the consequences of another vehicle crossing the central reserve at speed.

The outcomes are seldom less than catastrophic and, if the crossing vehicle doesn’t hit the motorcyclist directly, the other vehicles' resultant random evasive acts will make a collision very likely. So safety fences are better than no safety fences, on dual carriageways and motorways. The question then moves on to which type of barrier or fence is best for riders.

In the case of steel safety barriers, despite appearances, the simple truth is it probably doesn’t matter – a collision with any of them is much of a muchness and the rider is unlikely to do well if any speed is involved. There is no evidence that I have seen in the UK that the wire ropes will cut limbs or heads off or that a conventional corrugated beam (“Armco”) is any more or less friendly.

There is only one key factor against which there is evidence: the posts. These are designed to fold over when impacted by a car, van or other vehicle. To a sliding human body, these “Z” section galvanized steel posts give nothing but unyielding grief. This is why, in some areas, lower panels are used on bends for roadside barriers where the tangential direction of a sliding rider will all but guarantee a barrier collision.

On the straighter alignment of dual carriageways and, in particular, motorways, the lack of curves reduces this probability considerably – but a risk of a sliding collision still remains.

Recently, one issue has raised the profile of steel safety fences among motorcyclists: the opening of the newly upgraded A11. The steel safety fence system chosen for the central reserve is a wire rope. I am baffled at this choice; not because it will be unpopular – that was quite obvious from past experience – and not because the road has curves and there are no under beam panels to protect a sliding fallen motorcyclist (which may help at this location), but because any form of steel safety fence was used at all on a new project.

There is an alternative to steel safety fences and I would be surprised if you have not seen it; it is a continuous concrete barrier. These provide a steel-reinforced concrete wall from well below the surface of the central reserve up to a height far greater that the 700mm or so of a steel fence This means that, unlike a standard-height steel safety fence, they will resist a lorry, coach or other large vehicle from crossing the central reserve and also work to assist drivers when oncoming lights can dazzle them.

There is no doubt that the initial cost of a concrete safety barrier is many times that of a steel safety fence at construction. "So what? Isn’t it supposed to be safety first?" you may say. But remember – even the government’s money cannot be spent twice. If money is to be used on a concrete safety barrier in East Anglia, it is no longer available for, say, re-surfacing an area or road that has become uneven and filled with potholes in Birmingham or bridge strengthening in Northumberland etc.

So that’s that, then? Well, no, it isn’t really. The key reason why is about how roads and other public assets are paid for.

Whatever it is called, there are two types of expenditure in business and public service: one is ‘Capital’ and the other is ‘Revenue’. If you think that you are not going to understand this part, don’t panic and hang on – I think that I can assist.

Revenue expenditure is when you keep repairing the roof on your dodgy old shed – it buys the felt, nails and possibly pays the local handyman for a couple of hours to do the job. The thing with revenue spending is that you have to keep doing it  and doing it and doing it again... it never ends.

Governments have become increasingly tired of revenue spending, seeing it as representing poor value, and is all a bit inconvenient when the work keeps having to be redone. The direction of government spending in the transport world is now definitely towards capital expenditure. This means buying all-new sheds… I’m sorry, that is taking it too far.

I’ll start that bit again. The government is investing many millions of capital in schemes like the A11 upgrade. The reason is that, by building roads and bridges with modern materials and technologies, we can have the economic and social benefits of modern transport systems that give more predictable, safer journeys to more road users.

So, borrow some money, buy a new good-quality shed and forget the annual felt, nails and grumpy old odd-job chap who just moans and drinks all your coffee. You can make the repayments on the loan out of the money you would have spent on those repairs, and your tools, lawnmower and motorcycle will stay dry and warm as well – what’s not to like?

In the case of the A11, I believe that this may have gone very wrong in respect of the barrier. As I am sure you will have experienced for yourself, every time there is a collision with a steel safety fence in a central reserve, there are at least two major delays to the road user.

The first is the collision itself. If it is very serious or fatal, this will mean a probable four-hour road closure for information to be gathered so that the road death investigation can take place. This investigation is not optional – it is a requirement in law that every tragedy is duly investigated by the police, so that the coroner may determine a cause of death and any subsequent criminal prosecutions take place.

Once it is all cleared up, the road is re-opened and probably with a line of bright and cheery reflective cones along what remains of the steel safety fence. As soon as possible after this is done, there will be more lane closures on both sides of the road and speed limits may be imposed. This is so that the specialist repair crews can safely get to the damaged fence to remove it, replace it and re-tension it all.

If you think that is a cosy, safe or easy job to do, it is not – I used to do it and, as a workplace activity, I assure you that it can redefine a person’s understanding of the word ‘scared’.

So that’s going to be a day or two of delays and it is quite often the case that a few more minor collisions will occur in the queues. Now this will just keep happening again and again every time there is a collision with the steel safety fence.

In addition to this problem, every single steel safety fence has a built-in problem: corrosion. I wonder if you can imagine just how much road salt is bounced off a motorway central reserve fence in 10 or 15 years? Neither can I, but shall we agree that it’s going to be a great deal? Put simply, however good the galvanisation process is, in my experience it will usually give only 15 to 20 years before the structural validity of the fence comes into question and the whole thing needs to be removed and replaced.

So what about if a bit more capital had been invested and a continuous concrete barrier had been installed on the A11? Well, in the event of a major collision, the road death investigation would have to take place just the same, of course. Once the area is cleared up, however, the road would be back in business with no subsequent attention: no lane closure, no queues and no shunts and bumps, missed appointments and general frustration. In fact, this would precisely meet the Highways Agency’s ambitions of capital investment to increase safe and predictable journeys for all road users.

The other outcome is that the UK’s motorcyclists would not be riding along these busiest of roads giving occasional sideways glances at so-called ‘safety fences’, which at best give us all very bad dreams and at worst can do us so much harm, should we have cause to slide under one at any speed.

Concrete barriers are not softer by any means and they will hurt if you run up against them, especially at speed – let us be quite clear on that. It is the case, though, that their continuous nature and the materials from which they are constructed are entirely compatible with the protective equipment that most of us choose to wear when riding.

A continuous smooth surface to bump into and slide along sounds very similar to a road surface to me. I believe that they should be the preferred option when constructing new works or carrying out major road upgrading projects.

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