Capturing Cardiff: M4 Relief Road

Does South Wales need another motorway?

The need for a new road to relieve traffic around Newport is being planned by the Assembly. The road would ease congestion and help build the Welsh economy, according to government ministers.



Environmentalists argue it would have devastating effects on the Gwent Levels, a Site of Special Scientific Interest (SSSI) and the largest of it's kind in Wales.

Why do the Assembly want to build another road?

At the moment, anyone who commutes by car along the M4 will know about the congestion between junctions 24 and 28 in rush hour. As traffic hits the outskirts of Newport at peak times it often comes to a standstill with tailbacks trailing for miles. A commute from Cardiff can take up to an hour.

The congestion actually raises green house emissions as cars slow down to a stop and start pattern. With this, the number of accidents increases as cars bump into each other, causing further delays.

A new 24km relief road to the south of the city between junctions 23a and 29 would free up traffic flow and encourage more business into South Wales from England.


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The new road, planned for a 2010 start, would create jobs for the local economy. As with most major roads, developments are being planned alongside including a housing development in the old steel works and industry in the docks.

So, what’s all the fuss about?

The Gwent Levels are home to the UK’s largest surviving areas of ancient grazing marshes and a complex system of ‘reens’ (drainage ditches). The reens are vital for the survival of unique and rare wildlife which will be irreparably damaged if the road goes ahead.

Rare wetland plants and invertebrates live in the reens and feed the rest of the ecosystem including otters, water voles and breeding waders.

The contaminated runoff from the motorway will pollute the reen system and seriously affect the water quality the wetland depends on. As the reens are all connected, the pollution will not only affect the areas surrounding the road but the entire system. Rarer invertebrates so integral to this system cannot tolerate any level of pollution which could cause the system to collapse.

The fast moving road will also impose a danger to mobile animals, such as otters, attempting to cross it.

What about the bigger picture?

Friends of the Earth argue building roads actually generates more traffic as people, encouraged by a free flowing road, are more likely to drive to work. The more traffic there is, the more CO2 entering the atmosphere adding to global warming.

14% of Welsh climate change emissions come from transport which would be more than likely to increase if the road is built. The Assembly’s Climate Change Strategy pledges to cut green house emissions by 3% each year until 2011. It even states transport emissions will stabilise then start to decline over the next ten years. The increased traffic from the new road would jeopardise these targets.

What’s the alternative?

Bore a tunnel at Brynglas
This was dismissed by the government back in the 1990s for being too expensive and the technology simply wasn’t developed enough. That was 12 years ago and hasn’t been readdressed by the Assembly since. Tunnelling engineers have told Friends of the Earth the technology is now available and not as expensive as previously thought. This could be a less intrusive alternative to the new road in the long term but could cause delays in the short.

Better Public Transport
Environmentalists argue one of the best ways to decrease emissions is to improve local public transport. At the moment, some villages like Magor have no train station to connect them with Newport or Cardiff despite a railway line running through the village. By improving rail links from the north into Newport together with a faster service connecting Newport and Cardiff to Bristol and London would immediately be a more attractive alternative to travelling by road.

Speed Controls
These have been an effective tool used on the M25. Special technology monitors traffic flow and can even predict where problems can happen. In busy times, traffic is reduced to 40 miles per hour. The journey home maybe longer but it would be smoother. With less stop and start movement emissions will be less too.

Southern Distributor Road already used by commuters as an escape from the busy M4 in rush hour, could be widened to create a better relief road. It would cause less impact on the surrounding area than a new road would.

What happens next?
In March the Business Case will be published outlining how the government propose to pay for the road. One way of paying could be in the form of a toll, like Birmingham’s M6 toll road. If this idea is taken on then commuters and businesses travelling from England may find themselves paying a double fee (including the Severn Bridge Toll) to enter Wales which could drive business away.

The recession could be the key factor in deciding whether the road goes ahead. Current economic climes suggest that the cost of it, predicted to be between £700million and £1billion could see the plans scrapped by the government. It really depends if the need to create jobs and develop the Welsh economy outweigh the cost to build it. Only then will the surrounding environment be called into question.