At ICE and SWIP’s Enabling Better Infrastructure event in June, Jason Hones, National Highway’s South West Regional Director, talked us through the challenges of maintaining National Highways’ 23,700 structures.
It is now around 50 years since the motorway and A-road construction heyday – when labour was cheap, health and safety was in its infancy, and quality control was patchy at best.
So it’s not surprising that, half a century later, signs of wear and tear are everywhere.
Spaghetti Junction
One example of such a structure is the fondly nicknamed ‘Spaghetti Junction’ (M6 Gravelly Hill Interchange) or, to use the fruitier words of local papers at the time, ‘the bowels of hell’. Built in the early 70s at a cost of under £11m, Jason’s trip down memory lane revealed everything we need to know about construction practices of the day.
Early traffic figures recorded 40,000 vehicles a day. Currently over 200,000 use the road daily, 26,000 of which are HGVs and more than 31,000 are LGVs.
Severn Bridge
The main cables of Severn Bridge were once thought to be safe from corrosion, but lessons learnt from around the world have shown that we can never be complacent with these structures. National Highways’ cable inspections have allowed them to identify, monitor and repair corroded wires and introduce dehumidification systems, crack wire detectors and enhanced surveys of the cables to control the environment they are in and reduce the potential for corrosion. To keep it operating safely, a 7.5T weight restriction was posed on 27th May 2025.
The challenge, Jason told us, was one of engagement and reassurance more than of technical difficulty. Relevant stakeholders included customers, hauliers and distribution hubs, Welsh Government, TfW, WECA, MPs and MSs, DfT and the Welsh Office, local authorities and the emergency services.
Network defects and incidents
Identification and prioritisation of defects is key to developing a forward programme that keeps our road users safe. But, in context of RIS3, allocating enough funds to do so will be a challenge.
In Jason’s words, “network defects are a challenge for our resources and a frustration for our customers”.
With flooding becoming more common and bridge strikes becoming more frequent, climate change poses a real threat to the health of our strategic road network. And that’s before you bring in human error…
For more on some of the region’s critical and fascinating projects, check out:
- A blueprint for the future: Gravity Smart Campus
- Realising the clean energy potential of the Bristol Channel
- Harnessing the potential of offshore wind with Celtic Sea Power (external link to Great South West website)