MegaProject 1009: Preferred route for UK’s GBP1.6bn tunnel
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The UK government, through the Secretary of State for Transport, has announced the preferred route for the A303 Stonehenge tunnel project, which it aims to deliver under Private Finance 2 (PF2).
The 13 kilometre route, between Amesbury and Berwick Down in Wiltshire, includes a tunnel inside the Stonehenge, Avebury and Associated Sites World Heritage Site (WHS) past the Stones and a much-needed bypass to the north of Winterbourne Stoke.
The Secretary launched a public consultation earlier in 2017 to take a decision. After considering more than 9,000 responses, together with further assessments, the Secretay was able to improve the route before recommending it to the Government.
The most significant improvements were a change to the route through the western half of the WHS and to the location of the western tunnel portal. Both of these are now much closer to the line of the existing A303 than they were before the consultation.
The preferred route avoids many important archaeological sites, including newly-discovered barrows just to the east of the A360. The modified alignment also avoids any risk of the road intruding on the view of the setting sun from Stonehenge during the winter solstice.
The government also revealed the total estimated cost of the route has risen from £1.4 billion (US$1.86 billion) to £1.6 billion (US$2.12 billion).
The UK's HM Treasury adopted a privately-financed design, build, finance and maintain (DBFM) approach to funding this scheme.
Highways England aims conduct a statutory consultation for the project in early 2018 and submit a planning application for a development consent order in late 2018.
Upgrading the A303 between Amesbury and Berwick Down into high quality dual carriageway will be good for the people and businesses of the South West and for the Outstanding Universal Value of the World Heritage Site.
As well as improving journeys, easing congestion and eradicating localized rat-running, the tunnel will enhance the setting of Stonehenge by reconnecting it with its surrounding landscape and removing the sight and sound of traffic.
The project is also fundamental to the Government’s aim to make the A303 an Expressway to the South West. Along with the A30 and the A358, it forms the most direct route between London and the South East and the South West. This road is vital for the local and regional economy of the South West.