A Moonshot for Motorways: how National Highways is transforming maintenance through experimental technologies

England’s 20,000 highways structures have a constant demand for inspection and maintenance. Yet for all their durability, they can bear unseen weaknesses – particularly those with ‘hidden critical elements’ such as post tensioned bridges, where deterioration of key structural elements can deteriorate with no outwardly visible indicators. 

Many structures on our Strategic Road Network (SRN) are expected to exceed 50 years of age by 2030 and they are increasingly difficult to inspect. UK standards are robust, yet full intrusive checking is impossible. And unnecessarily conservative approaches to structural safety can lead to premature closures or even replacements of serviceable structures. After targeted research over the past 20 years, National Highways recognised bolder action was needed. 

In 2023, Structures’ Moonshot project was launched: an ambitious initiative investing in, testing and validating a range of international non-destructive testing (NDTs) technologies. From the established to the experimental, the AtkinsRéalis and Jacobs-led project is pushing the boundaries of the global asset management community and better educating engineering specialists about the various methods available. 

This knowledge will be shared through our “Practitioners’ Toolkit”. Additionally, the project has successfully accelerated NDT trial and adoption in England through investment from National Highways via their designated Research and Innovation funds. 

Our toolkit will include ‘one-pagers’ that crystallise each technique’s strengths and caveats, meaning stakeholders don’t have to trawl through individual reports and laboriously compare seemingly incompatible metrics. Instead, they can select the right tool for the desired outcome, at a glance.  

While we’ve maintained the position that there is no ‘silver bullet’ solution, over the past two years we have been rapidly paving the way towards a new era of data-led asset management, with a focus on predictive and preventative maintenance. This is ultimately enabling us and the industry to better prioritise resources and mitigate costly and disruptive inspections. 

From feasibility to reality 

Using the Huntingdon Railway Viaduct as our proving ground, we conducted feasibility studies on technologies ranging from common approaches, such as ground penetrating radar, through to cutting-edge guided-wave and muon tomography technologies. We engineered a controlled demolition of certain spans, juxtaposing hydro-demolition to compare different non-destructive readings. This methodological rigor – involving 60 in-depth tests of 20 different technologies - has ensured quantitative verdicts: scoring each NDT method on sensitivity, specificity and operational robustness. 

One particularly exciting innovation was the muonFLUX system - by Estonian company GScan – which could easily be mistaken for a particle-physics experiment. Cosmic muons traverse steel and concrete, with interactions revealing density variations and atomic contrasts. GScan’s portable ‘hodoscopes’ track these ephemeral waves to reconstruct a 3D map of what lies within. 

Initial trials at Toddington revealed that muon imaging can indeed locate tendon defects and duct voiding, despite individual wire breaks remaining elusive under the present resolution. Limitations remain – the hodoscopes need to remain in place for several days, a continuous 450W power feed is needed and with nearly 100kg of instrumentation, deployment in some settings is impractical – yet muon topography has proven its potential. Augmented by ongoing hardware and software improvements, including AI, future iterations will continue to expand its effectiveness. 

Towards unified asset intelligence 

Data is key to making informed decisions about structures, yet vast volumes are separated by silos and rendered incompatible by proprietary systems. Recognising this, the Moonshot uses advanced BIM approaches in creating a federated data model, synthesising 3D scans, images, lidar scans and other data into a single, holistic model. 

As a ‘single source of truth’, the model weaves disparate NDT outputs into an interactive canvas or digital twin, allowing engineers to toggle between modalities and assess statistical accuracy against ground-truth demolition. 

Navigating the future 

For all the technological innovation, the Moonshot’s trajectory is not preordained. Trust in unproven modalities must be earned: engineers accustomed to callipers and cores may balk at analyses delivered through cloud dashboards and particle tracks. We are developing a rigorous body of evidence, demonstrating not only technological prowess but usability, transparency, and cost-effectiveness. 

Phase 3 aims to secure such evidence and prove Moonshot’s worth as an approach to Strategic Road Networks’ preventative maintenance and digital asset management. Trial deployments of muon tomography on in-service structures - including a half-joint segments, deck hinges and post-tensioned bridges – again supported by National Highways’ designated funds and grants from bodies such as Innovate UK.  

A call for collective ambition 

As our national network grapples with increasing traffic volumes, fiscal pressures have tightened and some structures are reaching the end of their theoretical designed lifespan. Optimising maintenance has never been more critical – both for safety and minimising disruption. 

The goal of Structures’ Moonshot is to break through conventional thinking – reducing reactive and unnecessary maintenance, augmenting generic inspection regimes, and updating legacy ways of working. 

By illuminating hidden deterioration, these technologies support decision-making, prioritise interventions and prevent unexpected failures. Structures’ Moonshot provides the blueprint, but it’s up to industry to follow it. 

Article by Chris Mundell, AtkinsRéalis Technical Director and Colin George, National Highways Deputy Head of Structures 

This article was originally published in PBC Today in July 2025.