The A428 Black Cat to Caxton Gibbet scheme is a project of national significance, not just for the infrastructure it’s creating, but for the new benchmarks it’s setting in digital construction and Lean methodology. I had the pleasure of sitting down with the two leaders who formed the partnership at the heart of this transformation: Christos Christou, who drove the project’s digital strategy and technical coordination, and Balazs Haraszti, the digital lead who delivered the complex systems and architecture. We explored how they moved beyond buzzwords to build a truly integrated, commercially-savvy project.
The Scale of the Challenge
Dr Martin Perks: Christos, to set the scene for our members, can you outline the scale of the A428 project?
Christos Christou: It’s a beast of a project, Martin. We’re delivering a 10-mile stretch of new dual carriageway for National Highways, valued at circa £1 billion. This involves 18 new bridges, a massive viaduct, and a team of around 800 people turning over £1 million a day. The challenge isn’t just physical; we’re managing over 10,000 individual assets and more than 6 million user-defined attributes.
Dr Perks: On a project of that magnitude, what was the strategic catalyst for deciding that traditional, paper-based methods just wouldn’t cut it?
Christos Christou: We knew the old ways; piles of paper, siloed teams, and quality checks after the concrete has gone-off, were a recipe for delays, disputes, and spiralling costs. We had to change the entire toolbox. The key strategic shift was to stop viewing the project in terms of kilometres of blacktop and start viewing it in terms of the potential quantity of data, information, and decisions needed to deliver it successfully.
The ‘How’: Architecting the Digital Hub
Dr Perks: That’s a major strategic pivot. How did you even begin to coordinate the technical solution to manage that volume of data?
Christos Christou: Our first principle was that this solution would not be a single piece of software you can buy off the shelf. We needed a sophisticated, integrated ecosystem, and it had to be bolted together from day one. This is where the partnership with Balazs was so critical. My role was to coordinate what we needed, based on a deep-seated Lean mindset. We facilitated a centralised Digital Working Group to define the purpose first; reviewing user needs, the nature of information inputs and outputs, and the task workflows. Only then, as a final step, did we select the software to drive efficiency and integration.
Dr Perks: Balazs, that sounds like a monumental integration task. As the one delivering the architecture, can you walk us through the components you and your team delivered?
Balazs Haraszti: Certainly. Christos is right; the purpose defined the architecture. We built a federation of best-in-class systems. At its core is the BIM, the 3D digital blueprint. My team’s task was to create the connections. A key integration was dynamically linking the BIM to the CostOS platform, which holds the project’s Bill of Quantities. This link is refreshed bi-weekly, creating a live 5D model (3D model + schedule + cost).
Dr Perks: So what does that 5D model allow you to do?
Balazs Haraszti: It means when a designer tweaks a bridge pier in the model, the commercial team sees the cost impact almost at once. The ‘brain’ managing all this is ProjectWise, our common data environment where every drawing and report lives. We then connected the network of applications to it, including tools like ESRI GIS and Survey 123, to create location- and model-based interfaces that are intuitive for the site teams.
The Lean Pay-Off: From Code to Cash
Dr Perks: This is all technically impressive, but the Lean Construction Institute is focused on value and waste. Christos, how does this digital framework you’ve strategised directly support a Lean philosophy?
Christos Christou: It is the purpose-built engine for doing exactly that. At its heart, Lean is about relentlessly cutting waste to maximise value. Our system attacks waste on multiple fronts. The biggest is the waste of defects. We’ve implemented a fundamental shift from the old, reactive model of quality control to a proactive one of quality assurance. The goal is simple but revolutionary: get it right the first time, every time. We also obliterate the waste of waiting. All engineers on site, throughout the supply chain, have instant access on their tablet to the very latest approved drawing, not a revision from three weeks ago.
Dr Perks: Balazs, how does the system architecture you delivered enable that ‘right first time’ goal on the ground, in the mud?
Balazs Haraszti: We digitised the workflows. An engineer or inspector no longer fills out a paper form or manually searches spreadsheets. They complete a digital checklist on their tablet. That checklist is already connected to all the information required for that specific inspection; the 3D models, the deliverables lists, the material approvals. They attach time-stamped photos as evidence. If a non-conformance is found, an observation is raised, automatically assigned to the right subcontractor, and tracked through to close-out. It’s a closed-loop system that builds an unshakeable, real-time audit trail.
The Commercial & Collaborative Impact
Dr Perks: Let’s talk about the bottom line. Christos, what does this do for the commercial health of the project?
Christos Christou: The commercial benefits are direct and transformative. First, as we’ve discussed, rework is drastically reduced, which is the single biggest cost-saving a project can make. Second, administrative overheads plummet. We’re automating repetitive, error-prone tasks, freeing up talented people to solve real problems instead of shuffling paper. But perhaps the most powerful benefit is that it builds digital trust. The A428 is being delivered under an NEC4 contract, which explicitly requires the parties to act in a “spirit of mutual trust and co-operation”. Our digital hub provides the technological foundation to make that contractual aspiration a reality.
Dr Perks: How does that ‘digital trust’ affect cash flow and risk?
Christos Christou: It has a direct impact. When a payment application is submitted, it’s backed by an immutable digital record of progress, often verified by drone-based reality capture that compares the as-built site with the design model. The client can see, objectively, that the work has been done to the required standard. As a result, payments can be approved faster, which is vital for the whole supply chain. It also de-risks the project by avoiding disputes. The NEC4 contract has very clear processes for managing defects and compensation events. Our digital hub creates a perfect, time-stamped record of every communication, instruction, and inspection. It moves contractual administration from the realm of opinion and argument into the world of verifiable fact. This doesn’t just resolve disputes; it prevents them from happening in the first place.
A Replicable Blueprint?
Dr Perks: You’ve clearly built something remarkable here. For other firms in the Institute looking to reproduce this, what’s the key lesson?
Christos Christou: The key lesson is that this is a partnership between strategy and technical delivery. You can’t just buy the tech and hope for the best. You must start with a genuine Lean mindset and, as Balazs’s team did, define the purpose of the tools first. The goal is to create an environment of transparency and collaboration, empowering people with the right information at the right time.
Dr Perks: And Balazs, from the technical delivery standpoint, what’s your advice?
Balazs Haraszti: Focus on integration and the user. The Digital Working Group was essential because it allowed us to define the user needs first. The selection of the software was the final step. The goal isn’t just ‘cool tech’; it’s about building a robust, connected ecosystem that creates a single source of truth and drives efficiency for the person on site.
Dr Perks: Christos, Balazs, thank you both. You’ve provided a true blueprint for how a deep-seated Lean mindset (the ‘why’), coupled with a world-class digital architecture (the ‘how’), can create staggering and tangible commercial benefits. A powerful lesson for us all.
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