Newtown in Wales pre-dates the ‘new towns’ created following a 1946 Act of Parliament by over 650 years, but suffers more than its fair share of the relatively modern phenomenon of traffic congestion.

 

The market town in the county of Powys has a population of 13,000 and sits at the crux of two trunk roads: the A483 heading up the spine of the country and the A489 which provides access to the west coast.

 

Twenty thousand cars and as many as 1000 lorries are thought to pass through Newtown each day, causing huge tailbacks at peak hours. And the misery for motorists is amplified whenever a high sided vehicle strikes one of two low headroom railway bridges on the outskirts of town.

 

But relief for traffic in the area and improvements to the quality of life for residents are now promised with the construction of a 6km long bypass around the southern edge of Newtown.

 

Four bridges are being built to carry the new alignment over a railway, roads, valleys and watercourses. In addition, three accommodation bridges and four underpasses maintain access for local road users.

 

One of the most notable new structures taking shape is a three span, 80m long bridge to carry the bypass over the Dolfor valley. Two slender concrete piers with crossheads, cast in situ and designed to minimise their visual impact on the valley, stand 18m high.

 

Their form has been described as resembling a pair of champagne flutes and they received structural beams of weathering steel, which were lowered into place in December.

 

Other bridges on the project are of single span design and include a skewed crossing of a rail line towards Shrewsbury. Several bridges will be clad in stone to soften their appearance. Five roundabouts are being built; four on the highway alignment and a fifth off line to improve access to an industrial estate. 

 

Completion of the bypass will be followed by a series of measures to detrunk the existing main road through Newtown including traffic calming, renewal of the highway asset and the introduction of cycle lanes.

 

“Newtown is a major pinch point on the strategic route network through mid Wales and local congestion causes rat running through residential areas and is hampering economic development in the town,” says project manager Nick Cleary of principal contractor Alun Griffiths.

 

“Traffic problems were first investigated in the area in 1969 and a preferred new route for a road was announced back in 1973 but the project was not taken forward again until the early 2000s when 21 options were considered,” he adds.

 

“Ten years ago several options were presented and over 90% of people favoured a bypass. This new road should ease congestion and improve access to economic areas of the town.”

 

The southern bypass of Newtown will be a wide single carriageway featuring a ‘two plus one’ alignment along most of its route, to provide overtaking opportunities for vehicles.

 

The direction of the two lanes switches in several locations, mostly to provide an extra lane on uphill sections. A one metre wide hard strip between the single and dual lanes will be painted red, over which vehicles will not be allowed to cross.

 

Changes to the alignment outlined in the road’s original design have removed the need for £9M of utility diversions and the saving has now allowed for a greater proportion of the road to feature an overtaking lane.

“This two plus one arrangement is seen on several bypasses in Wales and gives journey time benefits, provides overtaking opportunities, reduces driver frustration and provides added capacity where traffic projections do not justify a dual carriageway,” says Nick Cleary.

 

Two and a half million tonnes of soil and rock that include glacial tills, clays, silt and mudstone are being shifted on site and 350,000t of aggregate is being imported onto the project from local quarries. The road alignment features significant lengths of cuttings – up to 34m deep – and long lengths of embankment, up to 26m high.

 

Areas of new embankment that may be prone to slip failure are being stabilised by installing a ‘shear key’ footing of backfilled material on the front edge.

 

The project is making good use of GPS controlled plant and across the project a total of 15,000m3 of concrete will be poured for the structures, 1000t of structural steelwork installed and 80,000t of asphalt laid for the carriageway.

 

Silt fencing has been erected to prevent run-off from reaching secondary watercourses that feed the nearby River Severn, and a series of run off channels and settlement lagoons have been created to cater for heavy rainfall.

 

New embankments and cuttings being built to accommodate the highway alignment include a series of ‘false’ cuttings that visually screen the road from nearby properties and will reduce glare from vehicle headlights. Care is also being taken to accommodate protected animals including badgers, bats, dormice and otters.

 

Hedgerows are being planted and fencing will be installed beside the bypass to lead mammals into 16 new crossings beneath the road. Several oversize culverts have been specified to allow for the movement of bats.

 

An additional 90,000 plants are also being introduced to replace lost habitats and provide additional visual screening. Remains of a Roman road and pottery from the Iron and Bronze ages have been exposed on site and documented.

 

The new alignment also passes within 11m of the 400 year old Brimmon Oak, which was named Welsh tree of the year in 2016 and was runner up in last year’s European tree of the year contest.

 

Ground penetrating radar was used to survey the extent of the tree’s roots to make sure the highway foundation will not affect the oak. Near to the tree ground was built up by hand or using lightweight plant, with a reduced standard of drainage and fencing specified.

 

Training opportunities are being provided for the local community through a project skills academy, set up in association with local college NPTC. A new groundworker apprenticeship has been developed during the project with the college.

 

The road scheme aims to take on a total of 16 young people working towards either the groundworker apprenticeship or other courses covering civil engineering, quantity surveying and commercial activity.

 

Newtown bypass is being delivered on behalf of the Welsh Government. A spokesman said: “This congestion busting project is of national significance to Wales and will make the road network in the area more robust for the benefit of both the travelling public and the Welsh economy.

 

“We are also committed to the Active Travel Act to encourage people to walk and cycle more and have been working with Powys County Council to help deliver its local transport plan, including the provision of a new cycle way to connect a large area of housing and a local industrial estate.”

 

Employers’ agent Corderoy’s project manager Rhodri Gibson MCIHT adds: “This is a complex project with difficult topography and challenging ground, but when complete it will certainly improve road links through mid Wales, relieve the bottleneck at Newtown and improve business opportunities.”