Local authorities across the UK are under increasing pressure to deliver on net zero commitments.
For highways departments, the challenge is particularly acute. They face constrained budgets, ageing infrastructure, and competing policy priorities. While much of the focus has understandably been on energy use and decarbonisation of vehicle fleets, this will only take authorities so far. This is where circular material use can bridge the gap.
Materials circularity concentrates on keeping resources in use for as long as possible, at the highest level of utility, and reusing, repairing and regenerating products and materials at the end of their service life. This was a central theme of the CERCOM project, where ITEN partners demonstrated that circular approaches are not theoretical; they are practical, implementable, and directly relevant to highway delivery.
The link to net zero is straightforward but often underestimated. The production, transport and use of highway materials account for a significant proportion of lifecycle carbon emissions. Virgin material extraction, processing, transport, and disposal all carry a carbon cost.
While the traditional model has shifted from “take–make–dispose” to “take–make–recycle”, this is still fundamentally linear. Recycling sits relatively low in the circular hierarchy and is often, in effect, downcycling.
Taking a circular approach means rethinking how we consider replacing assets, and asking:
- How do we extend the life of what we already have?
- How do we reuse materials in place?
- How do we reduce demand for virgin materials altogether?
From Circularity to Practical Delivery
The evidence base for this already exists. The PIARC decarbonisation work highlights a clear hierarchy: start by reducing the need for new construction, then maximise maintenance and life extension, and only then consider new materials. Techniques such as in-situ recycling, warm mix asphalt, and optimised maintenance regimes are not emerging; they are proven. In many cases, they deliver both carbon and cost savings.
Very often, the challenge is not technical, but procedural. Procurement decisions can still be driven by lowest upfront cost. As found in the CERCOM work, even when environmental considerations are included in procurement documents, they can be unambitious in both scope and weighting.
A focus on cost is understandable given budget pressures, but whole-life carbon and whole-life cost need to be part of the decision-making process. A road that lasts longer and requires fewer maintenance interventions is likely to offer better value and lower emissions, even if the initial cost is higher.
Circularity is therefore not just an environmental issue; it is about resilience and risk. Recent geopolitical events have highlighted how exposed supply chains for key materials such as bitumen can be. Reliance on virgin materials leaves highway authorities vulnerable to price shocks and disruption. By contrast, making better use of local, recovered materials builds resilience and keeps value within local economies.
There is also a strong spatial dimension. Highway materials are heavy and expensive to transport. Keeping them in local loops, either at a county or regional level, reduces both emissions and costs. This is particularly important for bulk materials such as aggregates and soils, where transport can be a dominant part of the carbon footprint.
Understanding Material Flows
However, there are barriers. Many authorities do not have a clear picture of their material flows, what is coming in, what is being used, and what ‘waste’ is being produced. Without that baseline, it is difficult to identify where the real opportunities lie.
This is where a more structured approach becomes essential. Evidence shows that up to 45% of emissions are linked to the production of goods and land management, with purchased materials forming a dominant part of Scope 3 emissions. For highway departments, this is particularly significant.
Understanding material flows is not an academic exercise—it is a practical one. It provides:
- clarity on where materials are going
- identification of waste and cost hotspots
- practical opportunities for reuse and reduction
- evidence to support funding and reporting
There are also capability challenges. Circular approaches require different skills around material flows, lifecycle assessment, and circular procurement, which are not yet embedded across most highways teams. Standards and specifications can also lag behind best practice, sometimes unintentionally reinforcing linear approaches.
What Happens Next?
However, none of this changes the direction of travel. The work we have undertaken shows that achieving carbon neutrality in the road sector will require action across construction, maintenance, materials, and procurement, not just vehicles. So what does this mean in practice?
First, understand your material flows. Without that, everything else is guesswork.
Second, embed circularity into procurement and asset management. Make whole-life carbon and value standard, not optional.
Third, work with your supply chain. Innovation will not come from clients or contractors alone – it needs collaboration.
Finally, be prepared to challenge existing practice. Much of what is done today is based on precedent rather than evidence.
The opportunity is clear. Materials circularity is one of the most immediate, practical, and cost-effective ways for highway departments to contribute to net zero. It aligns with existing asset management principles, reduces risk, and delivers tangible benefits.
The reality is that most authorities do not yet have a clear picture of their material flows, and without that, net zero plans risk being incomplete. If you are not sure where your biggest material and carbon impacts are, that is exactly the point to start.
Feel free to get in touch if you want to explore what that looks like in practice.
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