Plans to close three junctions on the M4 in Wales have raised serious questions after it emerged the Welsh Government has not yet worked out the full traffic impact of the proposals.
The announcement was made with plenty of fanfare, promising bold action on one of Wales’s busiest motorways. But buried in the small print is a significant admission – the traffic figures that would normally underpin such a major decision simply have not been calculated yet.
The Welsh Government wants to close junctions 24, 25 and 26 on the M4, a stretch of motorway that carries thousands of vehicles every day through south Wales. The closures are being presented as part of a broader effort to manage traffic flow and reduce congestion, but critics are now asking how you can make that case without the numbers to back it up.
For anyone who regularly uses that part of the motorway, the junctions in question are well known. Junction 24 at Coldra, junction 25 near Caerleon and junction 26 at Malpas serve communities across Newport and the surrounding area. Closing them would force drivers onto alternative routes, and local residents and businesses have plenty of reasons to want to know exactly what that means for their daily journeys.
That is precisely the problem. The Welsh Government’s own documentation acknowledges that the detailed traffic modelling work has not been completed. In other words, they do not yet know how many vehicles currently use those junctions, where those drivers would go instead, or what knock-on effect the closures would have on local roads that would inevitably pick up the extra traffic.
This is not a minor gap in the paperwork. Traffic modelling is fundamental to any serious transport proposal. Without it, there is no reliable way to assess whether closing the junctions would actually improve things on the M4 or simply shift the problem somewhere else, quite possibly onto roads that are far less equipped to handle it.
Newport, which sits at the heart of this stretch of motorway, has long been sensitive to anything that affects traffic movement through the city. The local road network already comes under significant pressure during peak hours, and any additional vehicles diverted off the M4 would feed into streets and routes that were never designed to absorb that kind of volume.
The Welsh Government has faced criticism before over its approach to major infrastructure decisions. The scrapping of the M4 relief road around Newport back in 2019 was a hugely controversial call, and transport in this part of Wales has been a political flashpoint ever since. That decision left a significant question mark over how congestion on this corridor would ever be properly addressed, and years on, that question has not gone away.
Now, with these junction closure plans emerging without the supporting evidence in place, there are concerns that decisions are being driven by policy preference rather than solid data. Transport campaigners and local politicians are likely to push hard for the full traffic assessment to be published before any firm decisions are made.
The Welsh Government has said the work is ongoing and that proper assessments will be carried out. But the sequence here matters. Announcing closures first and promising to work out the impact later is the wrong way around, and people living and working near those junctions deserve better than that.
For commuters, haulage firms and local businesses that depend on easy motorway access, the uncertainty is frustrating. The M4 corridor is a critical economic artery for south Wales, connecting Newport, Cardiff and the wider region to England and beyond. Any changes to how it operates need to be handled carefully and transparently.
Until the Welsh Government publishes the missing traffic figures and shows its working, these plans will continue to attract suspicion rather than confidence.