Posted by: wesleyjohnston | July 15, 2012

Reasons to support the A5 WTC dual-carriageway

The DRD is currently bringing forward a plan to build an entirely new grade-separarated dual-carriageway along the route of the A5, from Derry to Aughnacloy. The scheme is known as the A5 Western Transport Corridor, or A5 WTC.

This week the BBC reported that the Public Inquiry into the A5 upgrade, which took place in Spring 2011, will approve most of the road, although recommending that the stretch from Ballygawley to Aughnacloy be postponed, and asking the DRD to revisit the issue of compensation for landowners. I would expect a formal announcement on this subject within the next few days or weeks.

This particular scheme has attracted a storm of controversy. Supporters say that it will encourage investment in the West by providing better transport links, and improve road safety. Critics point to the large number of landowners – mostly farmers – who will be adversely affected, and what they regard as the excessive £844m price tag. Some also argue that anything that encourages the use of private cars should be avoided.

Throughout the years, one of the main reasons for such a divergence of views is not so much disagreement with the specific points made by the “other side”, but rather how much weight they give to those points. This is because the two sides are using fundamentally different evaluation techniques.

Roads Service’s arguments for the scheme are generally concrete and numeric, based on cost-benefit analyses and road safety statistics. Arguments against the scheme are generally more sociological and ideological, based on the impact on individuals, society and the environment. It is hard for concrete/numeric arguments to be weighed against sociological/ideological arguments in any meaningful way. Hence disagreement, impassioned debate and a lack of consensus is almost guaranteed in such proposals.

What I will be doing below is outlining the main arguments for proceeding with the A5 scheme. Counter-arguments are being adequately presented elsewhere. Everyone should make their own judgement based on common sense.

The current road is a single-carriageway road (i.e. one lane each way separated by a white line) and is all-purpose (i.e. all types of vehicle are permitted to use it – lorries, vans, cars, motorbikes, bicycles, tractors, horse-drawn vehicles, pedestrians etc). I have not measured journey times along the A5, but I would estimate that the average vehicle speed lies somewhere between 40 and 50mph. The new road will safely permit sustained speeds of up to 70mph for cars.

Benefit-Cost Analysis

The DRD has used a benefit-cost analysis to support the scheme. A benefit-cost analysis is achieved by estimating the average travel time saving along the route, and multiplying this by the number of vehicles predicted to use the route over the evaluation period (e.g. 20 years). This is then multiplied by a typical hourly wage figure (e.g., the minimum wage) to achieve a total saving to the economy over the period. Added to this, then, are the additional benefits to the economy, for example new businesses and jobs attracted to the area by the new road. Also added in are the money saved by the state from dealing with fewer accidents, in terms of the effect of road closures, and the cost to property and the NHS.

For the A5, the benefit-cost ratio was around 1.99*, which means that it will likely bring almost twice as much benefit as it will cost to build. Thus it is calculated to bring around £1.68 billion of benefits over the evaluation period, compared to its cost of £844m.

While this is a very useful sum, and all of these are real benefits, personally I have never been that convinced of the usefulness of this figure. Of course the haulage industry will make real, tangible cost savings from reduced journey times and delays, but most other drivers will not. Most people base their time of departure on their desired arrival time, and then subtract the journey time. Saving 15 minutes on the journey will probably just mean leaving 15 minutes later. In most cases, this will probably not mean a real, tangible saving of actual money. It might just mean an extra 15 minutes in bed, or a more leisurely lunch. The “benefit” figure, therefore, is merely symbolic, a way of making the intangible tangible.

The journey time saving is used in equally silly ways by the scheme’s opponents. Some take the total cost of the scheme and divide by the time saving that could be achieved by someone driving the full length of the A5, and then stating things like “the road is costing £50m per minute”, as if the entire road is being built for the benefit of a single motorist on one journey. This quite consciously makes the scheme sound ridiculous, but is a fairly meaningless figure when you consider that literally tens of millions of people will be using the new road over the next 20, 30 or 40 years. It also falsely suggests that shaving 15 minutes off a journey is the principal motivation of the scheme.

I believe there are two key arguments for proceeding, which I outline below. Of course there are other points to consider, such as whether now is the time to go ahead, or whether this is the road to be spending the money on, or whether farmers will be adequately compensated, but those are questions for another blog entry. For now, these are two of the best reasons to proceed.

1. Improved Road Safety

The current road has a poor safety record. Between 2004 and 2009, 19 people lost their lives on the A5 between Derry and Aughnacloy, an average of about one every 16 weeks. When total traffic levels are taken into account, we can calculate that 8.4 people are currently dying on the A5 for every billion kilometres travelled, which is around the average for roads of this type in Northern Ireland.

The graphic below shows where these deaths took place (along with the average vehicles per day, vpd, on each stretch):

Accidents and traffic volumes on the A5

Map showing (a) total deaths in the period 2004-2009, and (b) indicative 2009 traffic volumes on various sections of the A5. Note that one of the deaths between Ballygawley and Aughnacloy was on the treacherous stretch at Tullyvar which has since been removed.

Although we often hear news stories that suggest that “speed” is the dominant cause of deaths on our roads, in fact this is not the case. The roads with the highest speeds in Northern Ireland are also the roads with the lowest death rates – motorways have a death rate ten times lower than single-carriageway roads like the A5. Hence other factors must be at work. Most accidents are caused by poor or careless driving. But because drivers are human it is unavoidable that they occasionally make mistakes and poor judgements. The trick, therefore, is to minimise the opportunities for drivers to make errors. Experience has shown that the most effective way to reduce accidents on major roads is to systematically eliminate the causes of conflict between different vehicles. These include things like:

  • Minimising high speed differences by preventing vehicles from having to come to a near standstill on the road to turn on or off the road, usually achieved with slip roads.
  • Minimising the risk of striking a turning vehicle by banning right-turns, by providing flyovers to let drivers turn right without crossing opposing traffic.
  • Minimising the risk of head-on collisions by providing a central safety barrier, and also by providing a dedicated second lane in each direction to permit safe overtaking.
  • Minimising the number of junctions by banning most or all private accesses, and limiting access to local roads to a few carefully selected locations.
  • Minimising accidents resulting from leaving the road at bends by allowing only gentle, sweeping curves with plenty of forward visibility.
It is trivial to demonstrate the positive effect of these simple measures by comparing the death rates for various types of road in Northern Ireland (in each case per billion km travelled):
  • Motorways – 0.8 deaths
  • A-Class Dual Carriageways – 4.2 deaths
  • A-Class “normal” roads, like the A5 – 8.9 deaths
  • B-Class and below – 6.0 deaths

So normal (i.e. single-carriageway) A-class roads have the worst safety record of any type of road while motorways, which have all of the features outlined above, have the best. Clearly, then, upgrading the A5 will lead to lives being saved. The proposed A5 will be of a higher standard than the “A-Class Dual Carriageway” in the above list, in that most A-Class DC’s in Northern Ireland still allow right-turns and T-junctions. In fact, the proposed standard is just a little below that of a motorway; the only significant differences being that slow vehicles such as tractors are banned from motorways but will not be banned from the upgraded A5, and that the new road will not feature hard shoulders.

It is obvious that upgrading the existing A5 could not achieve the standard necessary to reduce deaths significantly. There would still have to be plenty of T-junctions, lots of private accesses, steeper curves, poorer forward visibility and (incidentally) significantly more property demolition. An upgrade of the existing road would offer some benefits, but would result in a more dangerous road than that which is proposed, offer fewer benefits than the proposed scheme, and lead to more deaths than the proposed scheme.

But even if we take the figure for A-Class DCs as the reduced death rate that will result from upgrading the A5 (and it’s probably too high) the number of deaths over the six years following construction could be expected to fall from 19 to 9. In other words, after six years ten people will still be alive who would have been dead had the upgrade not taken place. To facetiously borrow the phraseology of the road’s critics, this works out at £84m to save a human life.

2. Reduced Driver Stress

Some have (correctly) pointed out that the majority of the A5 is currently running below capacity. A single-carriageway road such as the A5 will generally perform adequately up to about 13,000 vehicles per day. As you will see from the map above, only the Omagh and Strabane throughpasses, and the stretch connecting those two towns, exceed this level. It is notable that the short stretch from Ballygawley to Aughnacloy is much lower than the others.

However, this is not an argument for saying that the upgraded road is not needed. A capacity figure is purely a reference to traffic congestion. It does not say anything about the general safety of the road, although increased traffic will tend to increase conflicts and hence accidents. Neither does it say anything about driver stress, which is a more important consideration for investment.

Driver stress is created whenever a driver is forced to drive in a manner that is below the way they would “like” to drive. Drivers are humans, not machines, and they respond like humans, not like machines. Anyone who has been stuck behind a tractor on a twisty road will understand how being forced to drive more slowly than you would like to can soon result in feelings of irritation and perhaps frustration.

Being stuck behind a slow vehicle with no means to get past is only one of many ways that driver stress manifests itself. Roads that require more concentration than others, perhaps because of numerous curves or lots of blind corners, create a more stressful driving experience. Being stuck at a junction waiting for a gap to turn out is another. Inching slowly through towns and villages on a long-distance journey is yet another. Each element by itself is not that significant, but added together a particular road may offer hundreds of tiny stress elements that add up and add up to create an overall stressful driving experience.

It is my view that the greater the amount of driver stress offered by a road, the greater the potential for accidents and the less willing people are to use the road. Why do most people choose motorways rather than parallel roads to go long distances? Because it’s quicker, safer and less stressful.

This is why the A5WTC will lead to increased investment in the West. By making it less stressful to get to/from towns like Omagh and Strabane, it will be enough to tip the balance for a lot of people who hitherto were not prepared to make the journey. This will make it more likely that new businesses will locate, or choose to remain, in towns such as these. It will also give greater freedom to the people living there, as leisure pursuits further away from their homes will come within each.

Bizarrely, providing a new road is one of the few areas where it is regarded as A Bad Thing if investment in a service results in more people using it. If you improve a shopping centre, or a visitor attraction, or a hospital, or a school you would not expect people to criticise it if it then attracted more people. Roads are a service, and they are meant to be used. In fact, there would be something wrong if a new road did not attract more traffic.

If the upgraded A5 succeeds, i.e. if traffic levels increase after it opens, it will be a signal that people are being given greater opportunities for commerce and leisure, and that people are investing in the West.

*A5 Public Inquiry transcripts, 9 May 2011, p132



  1. […] Firstly, to improve road safety. High-quality dual-carriageways have TEN TIMES fewer deaths than single-carriageway roads such as the existing A6/A5. Some may say “why not upgrade the existing road”? You could do this, but it would not be anywhere near as effective. For every 10 deaths on the A5 today, there would be about 5 over the same period if the existing road was upgraded, but just 1 if the road was upgraded as proposed. For more about this, see this blog entry. […]

  2. Well argued piece but surely the real argument is whether these schemes represent the best use of scare resources? Are their schemes that would more bang for bucks? Yes! York road. sydenham bypass, A6, A26 to Coleraine.

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