A358 Taunton to Southfields Road Investment Strategy Scheme - - PowerPoint PPT Presentation

A358 Taunton to Southfields

Road Investment Strategy

Scheme Specific

• “Create a dual carriageway link from the M5 at Taunton to the A303 incorporating

upgraded stretches of the existing road into the strategic road network where appropriate.”

• “The A303/A358 will provide an Expressway corridor from London to Exeter via the

M5 at Taunton, creating a second strategic corridor to the region.” Expressways “At a minimum, this means:

• Largely or entirely dual carriageway roads that are safe, well-built and resilient to

delay

• Junctions which are grade separated, so traffic on the main road can pass over or

under roundabouts without stopping

• Modern safety measures and construction standards
• Technology to manage traffic and provide better information to drivers.”
• Provided in 14 years

All Options

Fully online option (option 3) ranked 22 in the first EAST sifting process and dropped due to poor performance.

Top 4 Options following sifting

Option 2/2D Option 8A/8B + J25 Option 13

£526m £512m £505m

Option 1

£462m

Reduced Cost Options

All four options underwent a value engineering exercise that considered the following cost reduction measures:

• Development of vertical alignment to optimise earthworks;
• Rationalisation of side road strategy
• Discard some Expressway core requirements
• Focus on online widening

Following this the options were still coming through as unaffordable ranging £455m-526m. A further Value Engineering exercise was undertaken in an attempt to drive down costs to within budget. Out of this additional options were developed. Core Option 1/1B

• At grade connection with the existing Southfields Roundabout
• Online widening along the existing A358 between Southfields and Hatch Beauchamp
• Limited movements junction at the M5 comprising only south facing slip roads

Core Option 8/8B

• At grade connection with the existing Southfields Roundabout
• Online widening along the existing A358 between Southfields and Hatch Beauchamp
• No new connection to M5 Junction 25
• NFS (North Facing Slips) = provision of north facing slip roads at the M5 enabling all movements interchange between the M5 and the

new road

• J25 (Junction 25 Connection) = Connection into the existing Junction 25 roundabout.

Option Central/most likely estimate pre and post VE work Commentary 13 £512m Option dismissed on affordability grounds 2 £415m Development / rationalisation of option 2/2D (Awaiting commercial estimate) 1/1B +NFS £462m £386m Option 1 with an all movements junction on M5 motorway 8/8B + J25 £505m £401m Option 8/8B (with a connection in to junction 25) cost reduced through VE exercise. 8/8B+NFS £366m Option 8/8B (with an all movements junction on the M5 but no connection to J25). 8/8B £358m Option 8/8B (South facing slips on M5 only)

Is there a £251m option?

An exercise was undertaken to explore how much work can be undertaken for the budget of £251m. There is not a deliverable RIS compliant option available because:

• There is not a DMRB compliant option.
• There is not an expressway compliant option.
• Possibly some phased large scale local upgrades would be possible for

example: – Henlade Bypass; – A378 Junction upgrade; – Southfields grade separation; – Online dualling of some of the existing A358; – Offline dual carriageway Capland to M5

Online Option Revisited

• Jct25 is at capacity
• Negative environmental

impact on AQMA

• Severance at Henlade
• Sustainable transport
• ptions are weakened
• Low score at sifting

Online Considerations

Not RIS Compliant Vertical alignment very

• poor. There is a

pronounced hump in the road that is equivalent to the alignment for a design speed of 20 – 30mph. Cost and practicality dictates offline section here. Significant impact on existing residential areas, including substantial side road

• work. The cost of this

section will be disproportionally high due to residential land costs and impact on Henlade. Existing Air Quality Management Area. Additional Traffic Flows will increase pollution to unacceptable levels. Existing Junction 25 is at capacity. Substantial work may be required to upgrade the junction and this is not in accordance with the RIS Not RIS Compliant SCC Plans for routing A358 traffic through park and ride site is likely to cause unacceptable congestion and suppress benefits. Offline solution in this area would be require to prevent conflict with SCC plans, meaning a connection into the new development roundabout is the only option. This would not be RIS compliant. New Junction Required to Pick up A378

Online Considerations

Not RIS Compliant Vertical alignment very

• poor. There is a

pronounced hump in the road that is equivalent to the alignment for a design speed of 20 – 30mph. Cost and practicality dictates offline section here. Existing Junction 25 is at capacity. Substantial work may be required to upgrade the junction and this is not in accordance with the RIS Not RIS Compliant SCC Plans for routing A358 traffic through park and ride site is likely to cause unacceptable congestion and suppress benefits. Offline solution in this area would be require to prevent conflict with SCC plans, meaning a connection into the new development roundabout is the only option. This would not be RIS compliant. New Junction Required to Pick up A378

Option 2 (Mainly Online)

RIS Compliant and incorporates the following assumptions:

• Connectivity to M5

Jct25

• Henlade by-pass
• South facing slips
• Dual 2 lane trunk road
• Expressway ready

• John Hayes letter tpo Marcus Fysch MP - states

– When we met we discussed your concerns that Highways England has, at this early stage, included

• ptions that do not include a link between the

proposed new dual carriageway A358 and the existing M5 junction 25 and its connections into

• Taunton. I can assure you that I fully understand your

concerns and the need for this scheme to support the local economy as well as regional and national needs. I will ensure that Highways England takes this priority into account as the scheme develops.

• E-mail from DfT to Highways England States:

– The Minister was sympathetic to Mr Fysh and agreed to get HE to stop considering options which did not have local support from MPs and LAs. When I pointed out the HE has to consider a wide range of options at this stage, even if not all

• f them were taken into the public consultation stage, both Mr

Fysh and the Minister said that the early options stage should

• nly include a range of options that include a connection at

J25, as there was no point considering options that were going to be dropped later and had no local support. The Minister was keen to convey this message to HE more generally, for all schemes, not just this one.

Proposed Options for Consultation

Proposed Options for Consultation

Proposed Options for Consultation

Recommendations

1) Take the following through to Public Consultation: Potential future link to M5 Junction 25

Key Milestone Dates

Milestone / Event Start Stage 0 01-Jun-15 Stage 1 18-Dec-15 Stage 2 02-Dec-16 Stage 3 19-Jul-17 Stage 4 02-May-18 Stage 5 25-Jun-19 Stage 6 19-Mar-20 Stage 7 21-Mar-23 Project Start 01-Dec-15 Commence Public Consultation March 2017 SGAR 1 Option Identification 08-Feb-17 Preferred Route Announcement 08-Aug-17 SGAR 3 Preliminary Design 01-May-18 DCO Application 31-May-18 SGAR 5 (Construction Preparation) 25-Jun-19 DCO Decision 12-Dec-19