IN Brief:
- FM Conway and National Highways have completed a low-carbon resurfacing project on the M4.
- The 5.7-mile scheme used hydrogen and electric plant, including JCB’s hydrogen 3CX backhoe loader and Sany electric equipment.
- The approach prevented an estimated 630 tonnes of CO2 and cut emissions by around 50% compared with conventional methods.
FM Conway and National Highways have resurfaced a 5.7-mile section of the M4 near Swindon using hydrogen and electric plant alongside recycled asphalt.
The work took place between Junctions 15 and 16 and included the first use of JCB’s hydrogen 3CX backhoe loader in the project setting. A Sany electric planer and 4.5-tonne electric roller were also used as part of the lower-carbon plant mix.
The approach is estimated to have prevented 630 tonnes of CO2 from entering the atmosphere, representing a 50% improvement compared with conventional resurfacing methods. The project combined lower-emission plant deployment with circular material use rather than treating machinery and materials as separate carbon-reduction measures.
FM Conway is one of the UK’s major infrastructure services providers and a significant asphalt manufacturer in the South East. Its wider carbon strategy targets net zero across its activities by 2045, with circular economy practices forming part of its approach to reducing material impact.
Highways maintenance is difficult to decarbonise because resurfacing is energy-intensive, plant-heavy, materials-heavy, and usually delivered under tight traffic-management windows. Any lower-carbon method has to work within programme, safety, quality, lane closure, and performance constraints.
The M4 project therefore moves beyond a simple equipment trial. Hydrogen and electric machines were deployed within an operational resurfacing programme, where productivity and reliability sit alongside emissions savings. Road maintenance cannot absorb methods that reduce carbon only by increasing programme risk.
Materials innovation is moving in the same direction. Murphy’s use of carbon-negative asphalt at its Golborne hub showed how lower-carbon surfacing products are moving from controlled trials into practical site applications. The M4 project adds network-level highways evidence to that shift.
Road surfacing has several decarbonisation levers. Recycled asphalt can reduce demand for virgin aggregate and binder, lower-temperature asphalt can reduce energy use, cleaner plant can cut site emissions, logistics planning can reduce transport impact, and improved quality control can reduce rework. Stronger results usually come when those measures are combined.
Plant availability will influence how quickly the approach can scale. Electric rollers and planers are becoming more visible, but fleet transition depends on purchase cost, utilisation, charging arrangements, battery capacity, servicing, and confidence in performance under repeated heavy use. Hydrogen combustion plant adds another pathway, particularly for equipment where battery-only operation remains difficult.
Supporting infrastructure will also shape adoption. Depots, mobile charging, hydrogen supply, grid connections, fuel logistics, and site planning all affect whether low-emission plant can be deployed regularly rather than occasionally. Demonstrator projects help build evidence, but repeated use will depend on procurement and operations catching up with machine development.
Clients will influence the pace of change. National Highways and local authorities can normalise lower-carbon requirements through specifications and frameworks, but requirements need to be aligned with market capacity. If the supply chain is pushed faster than equipment, charging, material, and logistics systems can support, costs and programme risk will rise.
Cost planning will also need clearer carbon metrics. Contractors need consistent rules on how savings are valued, verified, and balanced against cost, safety, performance, and programme. Without that consistency, lower-carbon methods can remain isolated project choices rather than becoming standard practice.
The M4 resurfacing programme gives the highways sector a practical example of combined plant and materials decarbonisation. Wider adoption will depend on repetition across routine maintenance works, where lower-carbon methods have to perform without special treatment.
