The Scheme

Background to Dualling the A9

The A9 corridor forms a strategic link between Central Scotland and the Scottish Highlands and is shown in Figure A.1, A9 Perth to Inverness Location plan. The 177 kilometre route between Perth and Inverness consists of seven single carriageway sections interspersed between eight existing dual carriageway sections. Approximately 129 kilometres of these single carriageway sections are proposed to be dualled in order to complete the overall dualling of the A9.

The Pass of Birnam to Tay Crossing project commences at the northern extent of the current section of existing dual carriageway that extends from Perth to the Pass of Birnam. It extends approximately 8.4 kilometres bypassing the towns of Birnam, Little Dunkeld and Dunkeld to the east and Inver and The Hermitage, which is a National Trust for Scotland (NTS) protected site, to the west. The tie-in point with the following scheme, Tay Crossing to Ballinluig, is approximately 0.75 kilometres north of the current River Tay crossing.

Project 2: Pass of Birnam to Tay Crossing

Design and assessment work has been ongoing for the Pass of Birnam to Tay Crossing section of A9 dualling since 2004, with DMRB Stage 2 design and assessment beginning in 2009. Following public consultation in 2016, the local community requested more detailed consultation be undertaken to review options and investigate if other suitable alternative options, that address community concerns, were available. As a result, Transport Scotland agreed to the A9 Co-Creative Process, which was developed in collaboration with the Birnam to Ballinluig A9 Community Group and undertaken in 2018.

The outcome of the innovative A9 Co-Creative Process was the Community’s Preferred Route, which was voted by the public. The Community’s Preferred Route Option includes a 1.5 kilometre cut and cover tunnel in the locality of Dunkeld & Birnam Station. The option also includes an at-grade roundabout in the locality of the existing junction at Dunkeld.

Following completion of the A9 Co-Creative Process, further assessment work was undertaken on the Community’s Preferred Route Option, which included consultation with key stakeholders and local residents. This assessment identified a number of challenges, which largely focussed on the construction complexity of the option, environmental impacts on local watercourses and capital and maintenance costs. As a result, and as good practice dictates that a range of options should be considered, three Additional Whole Route Options were developed. These options included ideas submitted by the public as part of the A9 Co-Creative Process and considered Transport Scotland and the local community’s objectives.

Murthly/Birnam Junction DMRB Stage 2 Assessment

Three junction options were considered at Murthly/Birnam for the Additional Whole Route Options, as shown in Figure A.2. The initial focus of the DMRB Stage 2 assessment was on the Murthly/Birnam Junction options to determine a preferred junction option, which would be taken forward into the Additional Whole Route Options. Based on the outcome of the assessment undertaken, it is recommended that Option 2, a grade separated junction in the locality of the existing Birnam Junction, with merge/diverge slip roads in the northbound direction and a merge slip road in the southbound direction, be utilised for the Additional Whole Route Options. This option limits construction within the River Tay floodplain, has the lowest overall effects on the landscape resource and lowest anticipated costs.

Figure A.2: Murthly/Birnam Junction Options

Description of Route Options

Key features of the Community’s Preferred Route Option (Option ST2A) and the three Additional Whole Route Options (Options ST2B, ST2C and ST2D) are summarised below.

Community’s Preferred Route Option (Option ST2A)

• On-line route, largely following the horizontal alignment of the existing A9 single carriageway.
• A9 dual carriageway in a cut and cover tunnel for approximately 1.5 kilometres, commencing at the southern extent in the locality of the existing Birnam Junction and terminating approximately 300 metres south of the existing Dunkeld Junction.
• Dunkeld & Birnam Station retained in its current position with Station Road reconnected to the station. Parking on top of the cut and cover tunnel.
• Access road proposed to properties on Birnam Glen to the west of the station (in close proximity to Ladywell Landfill site).
• Speed limit of 50 miles per hour (mph) required between the southern extent of the scheme and the proposed Dunkeld Junction to maintain safety within the tunnel section. 70mph speed limit for the remainder of the scheme.
• Murthly/Birnam Junction:
  • Grade separated junction in the locality of the existing private access to Murthly Castle.
  • Diamond layout, facilitating all vehicle movements. Overbridge provided across the A9, connecting to the B867 to the west.
  • Requires a connection of the B867 and Perth Road in the locality of the existing Birnam Junction, crossing the A9 at the southern extent of the cut and cover tunnel.
• Dunkeld Junction:
  • At-grade roundabout in the locality of the existing junction at Dunkeld, including a segregated left lane between the A923 and A9 south, facilitating all vehicle movements.
  • Provides connections to the A9 (north and south), A923, A822 and road to Inver.
• The Hermitage:
  • Left-in left-out junction on the northbound carriageway.
• Dalguise Junction:
  • Grade separated junction south of the existing junction with the B898.
  • Loops in the northbound direction and slip roads in the southbound direction, facilitating all vehicle movements.
  • Realigned B898 crosses the A9 on an underbridge, connecting to a roundabout on the east of the A9, which also connects to the southbound slip roads.

Additional Whole Route Option 1 (Option ST2B)

• On-line route, largely following the horizontal alignment of the existing A9 single carriageway.
• A9 dual carriageway lowered into a 150 metre long underpass structure in the locality of Dunkeld & Birnam Station.
• Dunkeld & Birnam Station retained in its current position with Station Road reconnected to the station. Parking on top of the underpass.
• Access road proposed to properties on Birnam Glen to the west of the station (in close proximity to Ladywell Landfill site).
• Speed limit of 70mph throughout.
• Murthly/Birnam Junction:
  • Grade separated junction in the locality of the existing Birnam Junction.
  • Loops in the northbound direction and a merge slip road in the southbound direction, with no southbound diverge slip road.
  • B867 and Perth Road connected, crossing the A9 via an underbridge.
  • Includes an underbridge to connect the existing private access to Murthly Castle to the B867.
• Dunkeld Junction:
  • At-grade roundabout in the locality of the existing junction at Dunkeld, including a segregated left lane between the A923 and A9 south, facilitating all vehicle movements.
  • Provides connections to the A9 (north and south), A923, A822 and road to Inver.
• The Hermitage:
  • Left-in left-out junction on the northbound carriageway.
• Dalguise Junction:
  • Grade separated junction south of the existing junction with the B898.
  • Loops in the northbound direction and slip roads in the southbound direction, facilitating all vehicle movements.
  • Realigned B898 crosses the A9 on an underbridge, connecting to a roundabout on the east of the A9, which also connects to the southbound slip roads.

Additional Whole Route Option 2 (Option ST2C)

• On-line route, largely following the horizontal and vertical alignment of the existing A9 single carriageway.
• Generally, the same level as the existing A9 throughout, raised in the locality of Dunkeld Junction.
• Dunkeld & Birnam Station retained in its current position.
• Birnam Industrial Estate acquired, and the land used to construct a car parking facility accessed from Station Road, incorporating approximately fifty spaces.
• A new pedestrian underpass structure, incorporating lifts, constructed below the proposed A9 dual carriageway, linking the new car park to the station.
• Left-in left-out junction on the northbound carriageway to provide maintenance access to the station building. No public vehicular access available to the station building.
• Speed limit of 70mph throughout.
• Murthly/Birnam Junction:
  • Grade separated junction in the locality of the existing Birnam Junction.
  • Loops in the northbound direction and a merge slip road in the southbound direction, with no southbound diverge slip road.
  • B867 and Perth Road connected, crossing the A9 via an underbridge.
  • Includes an underbridge to connect the existing private access to Murthly Castle to the B867.
• Dunkeld Junction:
  • Grade separated junction in the locality of the existing Dunkeld Junction.
  • Variation of a diamond layout, facilitating all vehicle movements, with northbound and southbound slip roads.
  • A822 and A923 connected, crossing the A9 via an underbridge.
• The Hermitage:
  • Left-in left-out junction on the northbound carriageway.
• Dalguise Junction:
  • Grade separated junction south of the existing junction with the B898.
  • Loops in the northbound direction and slip roads in the southbound direction, facilitating all vehicle movements.
  • Realigned B898 crosses the A9 on an underbridge, connecting to a roundabout on the east of the A9, which also connects to the southbound slip roads.

Additional Whole Route Option 3 (Option ST2D)

• On-line route, largely following the horizontal and vertical alignment of the existing A9 single carriageway.
• Generally, the same level as the existing A9 throughout.
• Dunkeld & Birnam Station retained in its current position.
• Birnam Industrial Estate acquired, and the land used to construct a car parking facility accessed from Station Road, incorporating approximately fifty spaces.
• A new pedestrian underpass structure, incorporating lifts, constructed below the proposed A9 dual carriageway, linking the new car park to the station.
• Left-in left-out junction on the northbound carriageway to provide maintenance access to the station building. No public vehicular access available to the station building.
• Speed limit of 70mph throughout.
• Murthly/Birnam Junction:
  • Grade separated junction in the locality of the existing Birnam Junction.
  • Loops in the northbound direction and a merge slip road in the southbound direction, with no southbound diverge slip road.
  • B867 and Perth Road connected, crossing the A9 via an underbridge.
  • Includes an underbridge to connect the existing private access to Murthly Castle to the B867.
• Dunkeld Junction:
  • At-grade roundabout in the locality of the existing junction at Dunkeld, including a segregated left lane between the A923 and A9 south, facilitating all vehicle movements.
  • Provides connections to the A9 (north and south), A923, A822 and road to Inver.
• The Hermitage:
  • Left-in left-out junction on the northbound carriageway.
• Dalguise Junction:
  • Grade separated junction south of the existing junction with the B898.
  • Loops in the northbound direction and slip roads in the southbound direction, facilitating all vehicle movements.
  • Realigned B898 crosses the A9 on an underbridge, connecting to a roundabout on the east of the A9, which also connects to the southbound slip roads.

Cost Estimates

Initial scheme cost estimate ranges have been prepared for each route option under consideration which are shown in Table A.1. The total outturn cost estimate includes pre-construction phase costs, construction phase costs, risk, opportunity and uncertainty, and inflation through to the end of the construction phase. Optimism Bias is also included, which is a factor applied to the estimated total cost of the work to overcome the tendency for designers to be overly optimistic in their forecasts of the costs and time required to construct a trunk road scheme. Operation and maintenance costs are not included in the total outturn cost estimates.

Table A.1: Cost Estimates

Route Option	Scheme Cost Estimate (Minimum) (Excluding VAT)	Scheme Cost Estimate (Most Likely) (Excluding VAT)	Scheme Cost Estimate (Maximum) (Excluding VAT)
Option ST2A	£1,008 million	£1,266 million	£1,626 million
Option ST2B	£420 million	£495 million	£629 million
Option ST2C	£405 million	£478 million	£546 million
Option ST2D	£303 million	£362 million	£420 million