Cost effective way to by-pass M4 Brynglas tunnels

John Osmond considers a report which finds congestion around Newport can be tackled at a third of the cost of the Welsh Government’s proposed new motorway






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Congestion on the M4 around Newport could be tackled at almost a third of the cost of the Welsh Government’s proposed relief motorway, according to a new report launched by the IWA today. The report The Blue Route: a cost effective solution to relieving M4 congestion around Newport puts forward an alternative that would cost £380 million compared with the estimated cost of a new motorway of at least £936 million.

Known as the Blue route, it would use a combination of the A48 Newport Southern Distributor Road and the former Steelworks Road on the eastern side of Newport to create a new dual carriageway.

The report, published jointly by the IWA and the Chartered Institute of Logistics and Transport, has been prepared by Professor Stuart Cole, a transport expert who has advised both the Welsh and UK governments. He says the case for the more expensive motorway option relies on an over-estimate of likely future traffic growth and fails to take account of the impact of the Metro light rail system.

“The issue is whether the Welsh Government’s present motorway option provides an unnecessary increase in capacity and in consequence unnecessary expenditure,” he said. “The Blue Route would deliver what is needed at a much lower cost and with significantly less impact on the environment.”

Professor Cole says a key question in deciding between the various upgrades is calculations about future traffic forecasts, arguing that the Welsh Government is over-estimating the trends.

The Welsh Government’s consultation paper M4 Corridor around Newport forecasts a need for 20 per cent more traffic capacity by 2035. However, a new motorway will divert up to 40 per cent of existing traffic away from the present M4. Professor Cole argues this is far more than is necessary to tackle future capacity problems. He estimates that in combination with the Metro the ‘Blue route’ would divert more than 20 per cent of M4 traffic from the existing motorway. As Professor Cole said:

“The consultation paper takes no account of the impact of rail electrification or the Metro developments along the M4 corridor. The Newcastle Metro built in the 1990s, and the Bordeaux Tram network completed in 2004, reduced peak traffic flows into those cities by over 30 per cent. A similar impact could be expected in Newport and Cardiff. Electrification of the South Wales Mainline alone would reduce M4 peak traffic flows by up to 15 per cent, the so-called ‘sparks’ effect which has occurred on most other similar electrification schemes. The Blue Route would solve the congestion issue on the M4 as it arises. Moreover, since it could be built sooner that the motorway it could ease congestion earlier. Combined with the Metro and rail electrification it would provide more than adequate relief to congestion over the period to 2035.”

IWA Director Lee Waters added:

“The Welsh Government has repeatedly said that sustainable development is ‘the central organising principle’ of its economic policy. The decision it makes on a new M4 will be the test of that.  The last Government decided a new motorway wasn’t necessary, but the current consultation offers a series of limited options – each one of them involving a new road.  Stuart Cole’s report sets out a way of building one with the least environmental impact, and in a way which can be afforded. If the Welsh Government means what it says about sustainable development it must take the proposal seriously”.

The Blue Route involves an upgrade of the A48 and the ‘Steelworks Road’ – a length of industrial roadway purchased by the Welsh Government in 2010 at a cost of £7.7 million. The roads would be re-constructed as a two-lane, dual carriageway at motorway standard and could be widened to a three-lane motorway at a future date if this is needed. The route would follow a line between the Magor Junction 23A to the east of Newport to the Tredegar Park Junction 28 to the west of the city. The Welsh Government’s proposed motorway would also connect with Junction 23A but follow a more southerly route through the Gwent levels further east to the Castleton Junction 29.

Professor Cole’s report says there are three main reasons why additional capacity is required to cope with peak period traffic congestion on the M4 around Newport:

  • The Brynglas Tunnels on the M4 directly to the north of Newport are an acute pinch-point, reducing a six-lane motorway to four lanes. There have been many instances when there have been closures due to traffic incidents at this spot. For instance, in July 2011 the M4 was closed for two days after a lorry caught fire in the Brynglas tunnels. Nearby structures – the Usk Bridge to the east of the Tunnels and the canal bridge to the west – accentuate the difficulty of any road-widening project.
  • There were faults in the original design of the Newport northern by-pass / northern distributor road, later linked in to the M4, including the lack of a hard shoulder for some of its length. This reduces its capacity for current traffic volumes.
  • The M4 is used by local traffic as a local distributor road for short journeys within the local urban area.

It is noteworthy that although the Welsh Government now quotes a figure of £936 million for a new motorway, in 2009 the then Deputy First Minister and Minister for Transport, Ieuan Wyn Jones, estimated the cost at £1.25 billion. As he stated on 21 September 2009:

“The estimated cost of the scheme in 2004 was reported at 1998 prices, whereas the current figure of £1 billion is estimated at outturn prices. The effects of inflation alone in that period effectively doubles the 2004 figure. In addition, the application of Optimum bias at 15% adds a further circa £150m. The remaining additional forecast of circa £100m can be attributed to additional construction costs such as increases in land fill/aggregate taxes, higher materials and labour rates, as well as more demanding environmental mitigation requirements.”

John Osmond is Editor of ClickonWales. The Blue Route is available to download from the IWA website here: http://www.iwa.org.uk/en/publications/category/publications.