Route map - Achievements at 5-year milestones

Achieving Net Zero Operation, Maintenance and Improvement of the TRN will require substantive changes to the way we operate and ongoing implementation of decarbonisation actions over an extended period of time.

The Route Map sets out a clear sequence of milestones covering the period from 2025 through to 2045, describing what we expect to have achieved at five-year intervals. The initial milestone period to 2030 reflects the Scottish Government’s ambition for rapid and substantial emissions reductions, with a target to halve emissions by the end of this decade. Many of the actions required to meet this goal can begin immediately, using existing technologies and practices that are already available or emerging at scale.

Beyond 2030, the pace of emissions reduction is expected to slow as the remaining sources of carbon become more difficult to address. Progress during this period will increasingly depend on the availability of new technologies, the development of low carbon materials and fuels, and the maturity of relevant markets, all of which carry a degree of uncertainty. As a result, the Route Map adopts a phased approach that combines early actions with longer term interventions as solutions become viable.

Throughout the 2025 to 2045 period, the delivery of these milestones depends on the parallel implementation of the organisational and behavioural enablers set out later in the document. Improvements to policy, data, asset management, procurement, skills, and collaboration are essential to unlocking emissions reductions and ensuring sustained progress towards Net Zero.

2030 Milestone – 50% Emissions Reduction

By 2030, a 50% reduction in emissions will have been achieved through a combination of early action, technology deployment, and improvements in operational practice.

Materials Transport

  • Logistics management has been reviewed and improved, resulting in a 5% reduction in transport related emissions.
  • Operating Companies are trialling zero emission heavy vehicles where they are operationally feasible.

Materials

  • Warm mix asphalt is used for the majority of surfacing works, delivering emissions reductions of approximately 15%.
  • The use of recycled asphalt planings has increased to 35%, with trials underway to expand use where it is not currently permitted.
  • Biogenic products are used for all road markings, reducing associated emissions by approximately 73%.
  • Lower carbon steel alternatives are being procured where available.
  • Use of recycled aggregates has increased to 80%.

Depots

  • Electric vehicle charging infrastructure has been installed at depots to support small fleet zero emission vehicles, with future provision for HGV charging under investigation.
  • Energy efficiency audits have been completed, with measures implemented to maximise benefits, including improved insulation, occupancy sensors and upgraded controls.
  • Air source heat pumps and solar photovoltaic systems have been installed where feasible to generate onsite renewable energy.
  • Certified renewable electricity is purchased to meet remaining depot energy demand.

Streetlighting and Roadside Assets

  • All roadside electrical assets, including streetlighting and illuminated signs, are powered by certified renewable electricity.

Plant and Fleet

  • The small fleet (cars and vans) transitions fully to electric vehicles by the end of 2030.
  • Drones and other innovative technologies are increasingly used to reduce mileage associated with inspections.
  • Emissions from diesel used in construction plant and site compounds have been reduced by 80% through the adoption of low‑ and zero carbon alternative fuels.

2035 Milestone – 60% Emissions Reduction

By 2035, a 60% reduction in emissions will have been achieved as technologies mature and low carbon practices become more widely established across the trunk road network.

Materials Transport

  • Preparatory work is underway for zero carbon materials transport, including engagement with suppliers and support for emerging vehicle and fuel technologies.

Materials

  • The use of recycled asphalt planings has increased to 55%.
  • Trials are underway for evolving lower carbon materials, including alternative binders and low carbon concrete.
  • Continued expansion of biogenic road marking products and lower carbon steel use.

Plant and Fleet

  • For the small proportion of plant and equipment where full electrification is not viable, appropriately certificated low carbon alternatives are in use.
  • All depots are equipped with the charging or fuelling infrastructure required to support full fleet transition.

2040 Milestone – 80% Emissions Reduction

By 2040, an 80% reduction in emissions will have been achieved, supported by widespread availability of zero emission transport, lower carbon materials, and mature supply chains.

Materials Transport

  • Zero emission transport of maintenance and improvement materials to site has been achieved, using vehicles powered by renewably generated electricity and green hydrogen.

Materials

  • Alternative lower carbon asphalt binders, such as biobinders, account for 25% of asphalt use.
  • Low carbon “green” steel accounts for 70% of steel used.
  • Low carbon concrete is used in 50% of applications.

Plant and Fleet

  • Nearly all heavy vehicles within contracted fleets are zero emission, with a clear programme in place to replace any remaining diesel vehicles as they reach the end of their operational life.
  • Increased use of drones and digital technologies has reduced mileage driven for inspections by 50%.

2045 Milestone – Net Zero Emissions (with Insetting)

By 2045, Net Zero emissions will have been achieved across operation, maintenance, and improvement of the trunk road network, with residual emissions addressed through high integrity insetting.

Materials

  • Alternative lower carbon asphalt binders account for 50% of binder use, building on earlier material innovation and market maturity.

Offsetting and Sequestration

  • The carbon sequestration potential of Transport Scotland land has been enhanced as far as practicable.
  • Residual emissions that cannot be avoided are addressed through responsible offsetting, in line with Scottish Government principles.

Looking Beyond 2045

  • Ongoing efforts continue to identify new opportunities to reduce emissions further as technology, materials and practices evolve, with the aim of moving as close as possible to absolute zero.

Enablers

Achieving Net Zero operation, maintenance and improvement of the Trunk Road Network will require substantive changes to how activities are planned, procured, and delivered. These organisational and behavioural measures are referred to as “enablers.” While they do not in themselves deliver quantifiable emissions reductions, they are critical to unlocking and sustaining the reductions set out in the Route Map.

Policy

In the short term, policies, standards, and processes will be reviewed to improve the integration of greenhouse gas emissions management into decision making. A gap analysis will be carried out against PAS 2080:2023 Carbon Management in Buildings and Infrastructure to clarify the actions required of Transport Scotland in its role as Asset Owner.

This review will include engagement with Operating Companies to identify any existing policies, specifications or requirements that may limit the effective implementation of the Route Map, including restrictions on the use of lower carbon materials or approaches.

Improving our Data

The development of this Route Map has provided valuable insight into the current carbon data landscape and has highlighted areas where data quality, coverage and assurance can be strengthened. Ongoing improvements to data collection and management will support effective implementation of the Route Map, enable progress to be tracked consistently over time, and provide greater confidence in reported emissions information.

Asset Management

Asset management approaches will be reviewed and updated with the aim of developing an Asset Management Strategy aligned with the Trunk Road Adaptation Plan. Key objectives include extending asset life, improving resilience to the impacts of climate change, and reducing the long‑term need for maintenance and improvement activities, thereby supporting emissions reduction over the asset lifecycle.

Depots

The current operating model, in which depot facilities are often shared with other organisations, presents challenges in fully quantifying and managing emissions. This model will be reviewed to assess opportunities for greater control over depot assets, including potential changes to ownership arrangements where appropriate.

Alongside this work, surveys will be undertaken to assess the feasibility of depot electrification, on‑site renewable energy generation and the provision of infrastructure to support the charging of fleet vehicles.

Supply Chain & Procurement

Operating Companies will be expected to operate Carbon Management Systems aligned with PAS 2080:2023 and to commit formally to emissions reduction targets in support of the Route Map, for example through initiatives such as the Science Based Targets initiative.

The approach to assessing greenhouse gas emissions within contracts will also be reviewed, including opportunities to strengthen requirements through carbon budgets, internal carbon pricing, or the use of Key Performance Indicators to encourage desirable outcomes. These changes will be developed collaboratively with Operating Companies and the wider supply chain to ensure they are practical, proportionate and deliverable.

Behaviour Change 

While technological solutions are essential, people and behaviour play a central role in delivering Net Zero. Building on commitments within the Carbon Management Plan, carbon literacy will be increased across Transport Scotland and its supply chain through targeted engagement and upskilling.

In addition to general awareness raising, specific training needs will be identified for roles with a direct influence on emissions, such as fleet and plant operators. Ongoing communication will support staff and partners to understand new developments and embed low‑carbon practices in day‑to‑day activities.

Collaboration & Innovation

As a national infrastructure organisation, Transport Scotland is well placed to work with industry bodies, manufacturers, and delivery partners to support innovation and accelerate the development of low carbon solutions. Closer collaboration will help provide confidence to the market that there is sustained demand for Net Zero products and services.

Within the supply chain, opportunities will be explored to support and incubate innovative ideas, including consideration of how promising concepts might be supported through pilot projects or targeted funding. The Route Map has identified key emissions “hotspots” that will inform priorities for research and development.

Through improved processes, stronger collaboration and a sustained focus on innovation, these enablers will support delivery of the Route Map and help achieve Net Zero emissions by 2045, with the responsible use of offsetting where required.