Accelerating the decarbonisation of Scotland’s Infrastructure

The Cross Tay Link Road (CTLR) will link the A9 over the River Tay to the A93 and A94 north of Scone. This will help to alleviate traffic congestion in the city centre and Bridgend, creating capacity in the city’s road network that will enable a shift to greener modes of travel, and facilitating sustainable economic development of Perth and the surrounding area.

Driving net zero

Carbon management has been at the heart of this project with opportunities to reduce emissions associated with the creation of the asset during the construction phase being explored from the start.

This has been accomplished by integrating the carbon management process within PAS 2080 into design choices and decision making then further into the procurement and delivery stages. An initial carbon baseline was developed prior to development of the specimen design to identify carbon hotspots. Over the course of the design process, various value engineering modifications were incorporated by Sweco which resulted in associated carbon savings from earthworks, structures and pavements of some 13,000 tCO2e.

PAS 2080 procurement

In addition to the carbon emissions minimised during the specimen design, it was recognised that it was important to ensure that PAS 2080 would be incorporated during detailed design and construction. To achieve this, Sweco worked with Perth and Kinross Council to integrate carbon management within the procurement of the works contract. Tenderers were challenged to propose projects that would result in a minimum saving of 14,100 tCO2e of CO2e compared with the specimen design carbon footprint. This element of the tender was weighted at 15% of the evaluation criteria, with the maximum reduction being awarded the highest score. This ensured serious consideration was given to this element.

Through this process, a commitment was established within the tender requirements for the successful contractor to deliver its proposed carbon savings during construction. The successful supplier submitted a proposal in excess of the 14,100 tCO2e target. The project is currently in the design phase, and the design and procurement process together are expected to result in a 26,300 tCO2e saving of carbon compared to the baseline design.

Cross-discipline collaboration

Sweco’s multi-disciplinary team also undertook a DMRB Stage 3 Design and Environmental Impact Assessment which includes specialists in Landscape, Civil & Structural Engineering, Highways, Hydrology, Ecology, Archaeology, EIA, Carbon, Agriculture & Forestry and Project Management.

Our landscape team has had a critical role in the delivery of the project, undertaking a full Landscape and Visual Impact Assessment; including verified photomontage visualisations, and a detailed landscape design for the scheme which is located within a nationally recognised ‘Garden and Designed Landscape’. In addition to the road corridor landscape, the detailed design also includes the creation of new woodland habitats, extensive SUDS with integrated wetlands and a green bridge. Highlights of the design include:

• A new post-tensioned reinforced concrete bridge over the railway and River Tay
• A new grade separate junction midway between Inveralmond Roundabout and Luncarty
• Approximately 6km of link road between the A9 and A94
• New roundabouts connecting the CTLR to Stormontfield Road, the A93, Highfield (for future Scone North development) and the A94
• An active travel route for the full length of the CTLR set back from the road and linked to existing routes with toucan crossings
• An improved corridor along the redundant section of the A9 including landscaping, active travel route and a park and cycle
• A wetland area to the north of Scone Caravan Park providing drainage as well as an attractive environmental feature
• A green bridge for connection of ecology on either side of the CTLR at Highfield Plantation Woodland

Key services

Our multi-discplinary solutions for this project include:

• Landscape and visual impact assessment 
• Visualisation 
• Detailed design 
• Stakeholder engagement 
• SUDS 
• Ecology & habitat creation 
• Landscape management plans