|Location Map ( geo)
|Highnam, Gloucester (SO795190)
|Chepstow, Newport, Cardiff, Bridgend, Neath, Port Talbot, Swansea
|119 miles (191.5 km)
|A40, A4151, B4231, B4228, B4293, A466, B4245, M4, A449, B4237, A4042, B4239, A467, B4487, A4232, A4161, A469, A470, A4119, B4488, A4161, A4050, A4232, A4226, A4222, B4268, B4524, A473, B4265, B4622, A4106, A4229, B4281, B4283, A4107, B4286, A474, A483, A4230, B4291, A4217, A4067, B4603, B4489, A4240, B4296, A4138, B4297, A476, B4310, A484
|Old route now:
|A40, A449, A474, A484, A4222
South Wales TRA
|Route outline (key)
The A48 is one of the main roads in South Wales, connecting the A40 with itself and running via the southern cities. Most of the road has now been bypassed by the M4 but parts retain their former importance.
Highnam – Lydney
The A48 is a fairly quiet road, except at peak periods when Gloucester commuters have to queue from as far back as Minsterworth in the mornings, and form a long stream of traffic heading out towards the Forest of Dean in the evenings. Historically, it could get extremely busy when the Severn Bridge was closed for whatever reason – Gloucester represents the next point upstream where the Severn can be crossed – but with the opening of the Second Severn Crossing nobody has to endure this detour any longer.
The section from Gloucester to the border with Wales was detrunked following the 1998 review A New Deal for Trunk Roads in England, in 2005/6.
If you time it right and are not in a rush, this section of the A48 is an extremely pleasant run. It passes through Gloucestershire's beautiful rolling countryside, and in places there are some spectacular views of the Severn estuary. Its signage once designated it a 'holiday route' (HR), and it is easy to see why, as it provides the traveller with a scenic prelude to Wales. For the road enthusiast, the first section from Highnam to Chepstow provides a variety of features; it is mostly a standard single carriageway route, but there are several sections of old-fashioned dual carriageway, and numerous overtaking lanes. Some of it is very wide, where three lanes have been reduced to two on account of the many fatal accidents that the road has witnessed, and since the 1990s it has been neutered by traffic-calming measures. Nonetheless, it still possesses a lot of its former character. There are four low railway bridges (where HGVs are instructed to use the middle of the road), and a number of old filling stations. The road also passes through the hearts of several villages.
The A48 begins at a three-arm roundabout with the A40 near Highnam, a few miles to the west of Gloucester. From there, it makes straight for the west bank of the Severn. On this first stretch, a glance across the Vale of Severn provides the driver (or their passenger, at least) with a panoramic view of the city dominated by its Norman cathedral; the Cotswolds are also visible in the background. Just after passing Minsterworth the road and river are separated only by a wall for a couple of miles or so, which is used by people watching surfers enjoying the Severn Bore.
As the road proceeds towards Westbury-on-Severn, it passes a popular local smokery on the right and enters the village with the impressive Westbury Court Garden to its left. From the descent into Westbury, it is possible to see the Severn meandering away into the distance; the twists and turns before the river suddenly doubles in width are clearly visible, as is the Severn Bridge in the distance.
Just after Westbury comes the only junction with another A-road along this stretch – the T-junction with the A4151 at Elton Corner; turn here if you wish to head up into the Forest of Dean. As it hugs the Severn, the A48 never actually enters the Forest, but from the A4151 and a number of B-roads that area is easily accessible as the A48 passes swiftly by.
Not far after Elton Corner, the A48 runs right along the Severn (and is not unknown to flood), before kinking to the right and then to the left, and heading steeply uphill into Newnham-on-Severn. Newnham is easily the most scenic settlement in the portion of Gloucestershire lying to the west of the Severn estuary. Besides the attractive views of the river itself, it boasts many tasteful Georgian buildings, a clock tower located in the middle of the village, and a grassy bank to one side of the main street that is covered in daffodils every spring. The highest point in the village is reserved for the church, and it is at this point that the A48 drops into a deep walled cutting that twists left and then right as the road leaves Newnham behind. The view on the exit from this walled section affords a spectacular view of the Severn, with the Severn Bridge stretching majestically across it in the distance.
The road then sweeps onward towards Blakeney, passing a number of pick-your-own fruit farms and the odd manor house tucked away behind the trees. It dips into and out of Blakeney, which has the look of a Forest of Dean town even if it is not officially recognised as one. The houses are mostly built out stone that is grey with a reddish hue, a hallmark of the Forest. Blakeney provides two more possible points of entry to the Forest: the former B4227, which heads towards Cinderford and passes by the Dean Forest Heritage Centre, and the former B4431 to Parkend and Coleford.
From Blakeney, a very fast sweeping section of road then takes the A48 to Lydney, at the Forest's southernmost tip, where there is something new for the A48; a bypass, single carriageway, running south and east of the town. The bypass is punctuated by two small roundabouts, and a crossroads. One of the roundabouts appears incomplete, but it does provide a link road to Lydney railway station and Lydney docks. There is also a level crossing where the historic Dean Forest Railway crosses the road. These days the railway only provides any service for the benefit of tourists with a taste for nostalgia, but the occasional steam locomotive does puff its way across. Here, the river has narrowed a little, and there was once a spindly metal railway bridge (on quite a busy line) over the river to Sharpness at this point; however, in the 1950s a boat collided with it and it was demolished.
Interesting, the original path of the A48 through Lydney retains green signs, and has not been re-numbered as a B-road. This road provides access not only from the A48 to Lydney's nondescript town centre, but it spawns two points to turn off for the Forest. From here, the B4234 heads all the way up to Ross-on-Wye, while the B4231 heads towards Bream and Coleford.
Lydney – Chepstow
Soon after the end of the Lydney bypass, the A48 passes through the attractive villages of Aylburton and Alvington, again both built largely from grey-red Forest stone. It then dips down into a small river valley and climbs back up again to a dual carriageway that passes by Netherend and Woolaston.
From then until Chepstow the A48 is relatively straight, following the site of a former Roman road. It heads through more rolling Gloucestershire countryside and through the hamlets of Stroat and Wibdon, before passing close to Tidenham where the National Diving Training Centre is located at the disused water-filled Tidenham Quarry.
The A48 then approaches Tutshill, the last English settlement along this route. At this point the traveller gets their last chance to head for the Forest of Dean before passing into Wales; these days, the B4228 to Coleford and the village of St Briavels begins on the A48 at a T-junction just outside Tutshill, but it once stretched down the sliver of land between the Wye and the Severn to the old ferry slipway and the army barracks that now lie beneath the Severn Bridge. If the temptation to see any of these things is spurned, the A48 then avoids Tutshill and Sedbury village centres by following a bypass opened in 1988, which takes the carriageway through a deep cutting and then over a high bridge across the Wye into Chepstow.
This modern bridge runs parallel to the older one carrying the Gloucester-Chepstow railway line, and it provides an impressive view of the town across the Wye valley. From here it is also possible (for the pedestrian – the walls on the bridge make it impossible for the occupants of a car) to see the
old Wye Bridge, a cast iron structure built by in 1816. This to carry the A48 when it descended from Tutshill in a vast arc on Castleford Hill, crossed the river, and ran up through the middle of Chepstow. The combination of the narrow town centre streets and single track bridge controlled by traffic signals that meant this part of the old A48 was a bottleneck, and the opening of the modern bridge and the re-directing of the A48 away from the centres of both Tutshill and Chepstow was a godsend for locals and through traffic.
The A48 narrowly avoids Chepstow's lively town centre and - with its signage now available in two languages - it climbs up through suburban Chepstow to meet the A466 at a roundabout. A right turn here will offer a wonderful journey along the Wye Valley to Tintern and Monmouth. A left turn (which is where the primary route goes) will take you to the M48 at Junction 2 and the old Severn Bridge, looking wonderful in white paint, or to the faster motorway route into South Wales.
Chepstow – Newport
The A48 itself heads west parallel to the M48 and M4 motorways as a non-primary route towards Newport. With a name like Pwllmeyric, the first village after Chepstow leaves the driver in no doubt about the fact that they have crossed the border into Wales. The A48 passes a garden centre that only opened a few years ago but which has become very popular in the area, and the Saint Pierre golf club, before meeting the B4245 at a roundabout that was built to replace a T-junction in the 1990s. From here, the B-road offers the option of heading for the village of Caldicott, which is best known for its castle, and the Severn Tunnel railway junction, which provides rail travel to Bristol and London. Early proposals for the Severn Bridge showed the M4 ending at a roundabout on the A48 near this point, but this idea was abandoned before it could be built.
Those who remain on the A48 will pass under the M48 (the former M4) and through the village of Crick, where the road splits to dual carriageway. This is a very old example of this type of road; it has a 50 mph limit and has been modernised at both ends to calm traffic, but for most of its length it consists of two narrow lanes in each direction, separated briefly by a neatly-trimmed hedge but for the most part by a simple verge. There are frequent unprotected turning gaps in the central reservation. The dual carriageway ends at the start of a bypass which takes the route around the village of Caerwent, but which provides access to the Caerwent army training facility. Much of this section historically had overtaking lanes, but an extensive section of what was once the middle lane has been replaced by a tarmac central reservation, leaving just one lane in each direction.
Beyond Caerwent there is a real treat: a long stretch of three-lane carriageway under the National Speed Limit, with unrestricted overtaking in both directions. This stretch gives a good impression of what the road must have been like back in the days when it was the main road from England to Newport and Cardiff.
The landscape is also now noticeably Welsh in character, as the road continues with occasional overtaking lanes and extensive hatched areas and filter lanes to Langstone, where it is rejoined by the B4245 from Caldicott. Shortly afterwards it passes a business park accessed via a fairly recent roundabout, and there is then a brief section of modern dual carriageway linking it the Coldra (M4 junction 24) on the outskirts of the city. This is where the A48 meets the A449 from Monmouth and the Midlands, and the the route it followed itself until 1935. This is also the place where the A48 meets the M4 for the first time, in what will be an intimate relationship for the next sixty miles or so. On the hillside above the motorway can be seen the Celtic Manor Resort.
From M4 J24 the A48 continues round the southern edge of Newport as a recently-built dual carriageway, with frequent roundabouts and signal-controlled junctions. It meets the A4810 link road to Llanwern steelworks and the M4 at Magor. It crosses the Usk by means of a new bridge and passes adjacent to the famous Newport Transporter Bridge before meeting the A4042, which passes through the centre of Newport before becoming a major road in its own right as it heads north to Cwmbran and Abergavenny. The old A48 through Newport town centre has been renumbered B4237. The A48 resumes its original route at the Ebbw Bridge Roundabout, where it becomes a four-lane single carriageway until it encounters the M4 again at the Junction 28 near Duffryn. The junction 28 roundabout used to be the terminus of the M4 until the 1970s, when the extension west was built. The roundabout also provides access to the A467 which leads to Risca and, via the A468 to Caerphilly, famous for its castle as well as for its cheese. To the south of the roundabout is Tredegar House.
Newport – Cardiff
Now the A48 runs parallel to the M4 through the village of Castleton, and then alongside the A48(M) to St Mellons on the outskirts of Cardiff. This road is mostly a four-lane single carriageway, with a few sections where there is a central reservation. This section provides another good impression of how the A48 must have looked as the main artery in South Wales, before the advent of the M4. It stops abruptly at a four-arm roundabout, where the original A48 continues towards Cardiff through Rumney along what is now the B4487, while the A48 turns right to meet the A48(M) at a one-way free-flowing interchange.
From here through eastern Cardiff the road takes on the characteristics of an urban dual carriageway with grade separated junctions, although it now has a 50 mph limit. The road now sweeps through suburban Cardiff, and past the Cardiff East Park and Ride, before passing to the north of the city centre now (the old A48 through Cardiff city centre is now the A4161). Eventually it crosses under the A470 at the bottom of a 3-level stack roundabout, located near the University Hospital of Wales. This is the point where most traffic bound for the centre of the Welsh capital, and such Cardiff Castle, the Principality Stadium (built for the 1999 Rugby World Cup), the Sofia Gardens international cricket ground, St David's Hall, and Cardiff University. Alternatively, following the A470 in the opposite direction will lead to Pontypridd, Merthyr Tydfil, and potentially as far as North Wales.
Continuing westward, the road standard reverts to a four-lane single carriageway, passing over the River Taff and through the usual mix of light commercial and residential properties. The speed limit is 40 mph. It is in this section that the A48 is rejoined by the A4161 and its original route through Cardiff at a three-arm roundabout. Eventually it reaches the relatively new A4232 Cardiff ring road at Culverhouse Cross, on the western fringe of Cardiff. The A48 passes over the A4232. Indeed, whilst historically, the A48 was the main road in Cardiff, it has largely taken a back seat to the A4232, as it is this road which provides the link between the M4 and the attractions of Cardiff Bay.
Cardiff – Bridgend
As it leaves the Welsh capital behind, the A48 becomes very rural in character. Since the advent of the M4, it has carried much-reduced levels of traffic. It passes through the villages of Bonvilston and St Nicholas, which are both characterised by thatched cottages and window boxes. The Cottrell Park golf course is located to the right. The road is mostly tradition a single carriageway, with the odd section where three lanes have been reduced to one. The road is fairly straight and very gently undulating, with long sweeping curves; it is also largely covered by street-lighting, although there are reminders that the National Speed Limit applies. There is also the odd warning that speed cameras might be in place. Eventually, the road arrives at St Hilary, where a 50 mph limit is applied shortly before the start of the Cowbridge bypass.
This section consists of about two miles of grade-separated dual carriageway. The bridges on the Cowbridge bypass have slightly unusual parapets. Instead of the three parallel rails normally seen on bridges, there is something that looks like a very beefed-up pedestrian guard rail. As each carriageway has its own bridge, it is possible to look through three sets of vertical lines – the effect is quite striking. One of the bridges provides a view across the town to the left. This dual carriageway provides another indication of the A48's age; there are two lanes in each direction with no run-off area; between the bridges, there is even a stretch with no crash barrier. At the end of the bypass, the A48 is joined by the A4222, which has taken over the old route through the town centre.
The A48 continues west towards Bridgend on a single carriageway which follows the ancient alignment of the old Roman road. It passes the Taskforce Skirmish Paintball Games Centre, which lies just off the main road to the right, before encountering a T-junction marking the beginning of the B4268 at Pentre Meyrick. Turn left here for Nash, and Llantwit Major, which is located just a short distance from the sea. After Pentre Meyrick, there is another long straight stretch where three lanes have been reduced to two, before another where a long climbing lane (in the opposite direction) has been left in place. At Brocastle a 40 mph limit is imposed and the road splits. The left fork sends the B4524 off to Corntown, Ewenny and Ogmore-by-the-Sea. The right fork takes the A48 to a roundabout leading to an apparently incomplete business park. The A48 then resumes its familiar 'three-lanes-reduced-to-one' configuration, and proceeds towards Bridgend. There is then dualled section with a level crossing, and a signalised turning to an industrial estate on the right. The A48 then crosses over the River Ewenney before cannoning off the A473 at a large roundabout.
These days the A48 passes south of Bridgend, but used to go right into the middle of town along the present A473. The old road can be accessed by driving straight ahead at the roundabout, while a turn to the right will take you up the A473 to meet the M4 at Pencoed. A left turn will keep you on the A48, along a single carriageway that is imaginatively named 'Bypass Road' as it passes south of Bridgend. It is punctuated by a number of roundabouts, one of which carries the B4265 out of the town towards Ewenny, St Brides Major and Southerndown on the coast. There is also another opportunity to enter Bridgend by taking the B4622, which leaves the A48 from one of the roundabouts to the right.
The A48 also passes under a bridge which carries the railway over the road towards the south coast, leading eventually to Cardiff airport and the seaside town of Barry. There was once a steel girder bridge over the road that used to have FERODO written on the side, although this seems to have disappeared. At the end of the bypass, the A48 then meets the A473 again at a three-arm roundabout west of the town. The A473 ends here.
Bridgend – Briton Ferry
West of Bridgend, the A4106 leaves the A48 via a roundabout to the left, bound for the seaside resort of Porthcawl, with its funfair. After that lies the Stormy Down section of the A48, another section of old dual carriageway. Much of it is tree-lined, and there are several No-U-Turn signs at the turning gaps. The A48 meets the M4 again for the first time since Newport, but there is no motorway access here; the A48 simply passes below its effective replacement. It then reverts to single carriageway with a climbing lane (in the opposite direction), all restricted by a 50 mph limit. Again, there are frequent No-U-Turn signs, although here they appear to be intended to deter HGVs from turning around in laybys. The road is briefly dualled again before a four-arm roundabout at Pyle, where the A4229 provides access to the M4 to the left, and the B4283, the second exit on the left, leads to the southern part of the town. Perplexingly, there are even No-U-Turn signs immediately before the roundabout.
The A48 heads right through the centre of Pyle, where it meets the B4281 at a crossroads. A turn to the left takes you out of town on an unclassified road that leads to the Kenfig National Nature Reserve. A turn to the right takes the B4281 up to Kenfig Hill. Once it leaves the town, the A48 is once again a wide, sweeping road with one brief section of dual carriageway. It passes through Margam, with its castle and country park, before meeting the M4 again at junction 38. The A48 runs parallel to the M4, down the hill on a dual carriageway to Junction 39. Here there is also a roundabout, where the A4241 heads down to Port Talbot harbour and the Port Talbot steel works.
At one point the M4 was the A48(M), and it took the A48 round Port Talbot to Baglan. These days the A48 passes through Port Talbot once more. As it enters the town, the A48 passes through the long suburb of Taibach before reaching the centre of Port Talbot itself. It passes Port Talbot Parkway railway station, and meets the A4241 again as it returns from the harbour. There is then a short section of dual carriageway, after which it meets the M4 again at Junction 41. Here there is a roundabout with a spur road offering motorway access to and from the motorway to the east, as well as to the other end of the A4241 which heads down to the beach in Baglan Bay.
It is at this point that the A48 regains primary status for the first time since Cardiff. It runs parallel as a dual carriageway towards the old Briton Ferry Bridge. This bridge is now largely superseded by the M4, and once you've crossed it, the A48 multiplexes with the M4 as far as junction 44. Built as the A48 in the 1960s, this road was converted to motorway in the 1990s. However, the original A48 ran north from Briton Ferry to Neath (now part of the A474), then west to Skewen and Morriston (A4230), on the northern fringe of Swansea.
Needless to say, the A48 bridge over the Neath used to be a very important section of road, not only linking the two sections of the then incomplete M4, but also providing Swansea with its quickest means of road access to Cardiff and beyond. The newer bridge, having completed the motorway and effectively replacing the old Briton Ferry Bridge on the A48, is clearly visible some distance away to the left.
Briton Ferry – Camarthen
The present A48 resumes at junction 44, and meets the A4217 at a signalised junction from which it is possible to turn south towards Swansea city centre. After a roundabout providing local access and a brief section of dual carriageway crossing over the River Tawe, the A48 meets the A4067 at a grade-separated junction. A left turn onto the A4067 here will offer you another chance to head for the city centre and, eventually, Swansea University and the Mumbles peninsula. A right turn onto the A4067 will take you back to the M4, and onward up the Tawe Valley towards Pontardawe and ultimately the A40 in the Brecon Beacons National Park.
The A48 runs through the town of Morriston. On your left, as you approach Llangyfelach, you will see the large DVLA building looming on the skyline, next to the crematorium. The road cannons off the M4 at Junction 46, through which the B4489 also passes, linking western Swansea with Felindre and the open countryside to the north. After meeting the A483 from Swansea and the M4 yet again at Junction 47, the A48 turns north at a roundabout with the A4240 in Penllergaer. While that road continues west towards Llanelli, the A48 continues to play second fiddle to the M4 through the villages of Pontlliw and Pontarddulais, before arriving at the end of the M4 (Junction 49).
While the A483 heads off at this point for central Wales, the A48 now finally asserts itself over the motorway upstart, becoming a high-quality dual carriageway for the remainder of its length. It regains primary status, lost since its multiplex with the M4 after the old Briton Ferry Bridge, and continues with some pride along an alignment built in the late 1980s to Carmarthen. The old road ran through some pretty little villages, but the most noticeable sight was the steep hill at Nantycaws just to the south of Carmarthen. Here, the road drops down a very steep gradient (1 in 4) before climbing back up an equally steep hill. You didn't want to get stuck behind anything there. The newer A48 takes a more gentle course, but you can still see the old road ahead of you at one point.
This final stretch of the A48 is quite varied for a modern dual carriageway. There are several grade-separated junctions, as well as at-grade junctions with turning gaps. The road is under the National Speed Limit throughout, although there are frequent signs warning of speed cameras and prohibiting U-turns. At Cross Hands, a roundabout with the A476 sees that road from Llanelli cross over our route towards Ffairfach on the A483. Shortly afterwards, the B4310 links the A48 to the National Botanic Garden of Wales.
Finally, the A48 meets its destiny with the A40 at Carmarthen, the same route that spawned it at Highnam near Gloucester. Over the years the end-point of the A48 has moved, as new roads have been built in and around Carmarthen. Today it terminates at a signal-controlled roundabout with the A40 and the A484 at Pen-sarn just south of the town itself, and before the modern Pont Lesneven crossing of the Tywi. On the approach to the roundabout, signs warn of peak-time queues, and a 40 mph speed limit is imposed. The A48 therefore finishes its journey much as it began.
Most of the A48 route has changed beyond recognition since it was created in 1922, with only sections around Tredegar Park, the route between Ely and Briton Ferry, and from Llansamlet to Penllergaer resembling the old A48 route. The 1923 route is illustrated in the navigable and zoomable map on the right.
The original route started at St. Johns, Worcester at the junction with the A44, then took what is now known as the B4206 Malvern Road south. It then took what is now known as the A449 to Ledbury. Through Ledbury, the road took what is now the B4216 New Street then rejoining back onto the A449 Ross Road to Ross-on-Wye. The route then went along what is now the B4234 into the centre of Ross-on-Wye to the junction of the then A40 (now the B4260). The route resumes at Wilton Castle along the now A40 Trunk Road through Pencraig onto Whitchurch, then onto the now unclassified road past Little Doward and Ganarew before following roughly the existing A40 to Dixton, to the north-west of Monmouth.
The route then went along the now A466 Dixton Road to the centre of Monmouth, then along Monnow Street and across Monnow Bridge. The route then turned onto the now B4233 down to the River Trothy. The route then went west along the now unclassified Monmouth Road through Mitchel Troy and onto Raglan.
At Raglan, the route again turned, this time to the south along the unclassified Monmouth Road to Usk, taking the now A472 at the east end of Usk westwards until it crosses the River Usk. The route turns south along the unclassified road through Langibby and Llansoar to Caerleon. At Caerleon, the route took the now B4596 through to Newport and back over the River Usk.
South of Newport, the route took Commercial Road, then west along the now B4237 Cardiff Road before following the existing Southern Distributor Road before joining the existing A48 route at Tredegar Park. The route then detours again near St Mellon's, taking the B4487 Newport Road across the River Rhymney, before taking the now A4161 to the River Taff in Cardiff. From here, the route went west along the unclassified Cowbridge Road East, then the now A4161 to the railway bridge in Ely.
Here, the route rejoins the existing A48 westwards to Briton Ferry, to the south of Neath, with three exceptions - through Cowbridge, the route took the now A4222; through Bridgend where the route takes the now A473; and through Baglan where the route followed Church Road and across the present Baglan Primary School site onto Old Road, just touching the modern A48 at Briton Ferry roundabout. From here, the route then went north along the current A474 into Neath, before taking the now one-way unclassified London Road. Across the River Neath, the route went west near the now A474 before taking the now A4230 through Skewen. The route then pretty much takes the existing A48 in the main to Penllergaer. From here, the route then continued straight onto the now A4240 through Gorseinon and onto Loughor. The route crossed the River Loughor at a now dismantled bridge to the north of the existing A484 road bridge, before taking the now B4297 through Llwynhendy and onto the then spelt Llanelly.
The route then continued westward along the now A484 to Carmarthen, except through Kidwelly, the route went along the now B4308. In Carmarthen, the road continued past the current A48 junction (then called the A475) along the now unclassified Pensarn Road, and across the River Towy on the current A484 to the junction with the then A40 (now A4242/A484)
In 1935 it was rerouted east of Newport along the A437, presumably to provide a more obvious route to the then-lowest bridge across the Severn. The old route was renumbered as part of a rerouted A449, although the section between Ross and Raglan became the A40 instead. Most of the Welsh section of this road has been heavily improved and the old route is now unclassified.
In Bridgend, the route took the new bypass which had opened on 26 March 1931, with the old route being renumbered A473
In West Wales, the original route between Penllergaer and Carmarthen was renumbered the A484, with the new route taking the existing A48 route to Cross Hands. From Cross Hands, the route took the now unclassified Pontarddulais and Carmarthen Roads to Draefach, before taking the now B4310 to Llandarog. The route then resumed the current A48 route through to Nantycaws, then went along Heol Llangynnwr, then the now B4300 to the Towy Bridge.
Following the completion of the Briton Ferry Bridge, the route changed between Briton Ferry and Skewen into a more direct route with one roundabout at the junction with the A483, no longer going via Neath.
|1926 - 1927
|Cardiff - Newport Improvements
|Diversions at Llanrumney, Goitre, Castleton, Dyffryn and west of Newport (Maesglas) were in the Ministry of Transport scheme proposals reported in the Western Mail of 13 April 1925. A visit to the Dyffryn Diversion was mentioned in a Western Mail report of 28 May 1927. It included a top concrete dressing of Betonic hardening material.
|The 5 mile road was opened on 16 March 1931 by Lieut.-Col. D. Watts-Morgan, Chairman of Glamorgan County Council Roads and Bridges Committee. Cost was £133,000 of which the Ministry contributed £97,000. Sections west of the River Ogmore bridge and between Heronston and Coychurch had opened by January 1929. Opened as A473. The section from Laleston to Heronston was renumbered A48 by 1934.
|The 0.6 mile section to cut out a dangerous corner by the old school to the east of Penhow was being opened on 16 May 1931. It was the first part to open of the Newport to Monmouth road reconstruction scheme. Opened as A437.
|Margam: Tollgate Road Diversion
|Neath Guardian of 24 July 1931 reported on a meeting of the Highways Committee that stated that £6,247 of Relief Grant Money had been spent on the road. It may have opened earlier.
|The 1.25 mile road was opened on 3 October 1932 by the Earl of Plymouth. Cost £27,000. It was part of a 5 year upgrade to the Chepstow to Newport road. Opened as A437.
|Cardiff: Western Avenue
|Opened on 11 July 1933 by Alderman C.F. Sanders, Lord Mayor. The 2.1 miles from A48 Cowbridge Road to A470 North Road included Cathedral Bridge over the River Taff. It was referred to as the Orbital Road. Opened as A4056.
|Listed in the completed County Council road schemes of 1933 (per the Western Mail of 8 January 1934). Cost £3,900. Opened as A4056. Later renumbered A48 then B4310.
|1933 - 1938
|Langstone and Llanbedr Diversions
|The schemes were reported as being deferred due to National cost constraints by the Western Mail of 9 January 1933. It is expected that the deferral was temporary and construction would have restarted shortly. They are shown on the 1938 OS Six inch map.
|The Dock Street bypass was opened on 5 November 1934 by Alderman John Moxon. It involved the culverting of the Monmouthshire Canal and a diversion of a railway. The section from High Street to Skinner Street was on a 600 foot viaduct, of 53 foot width, due to the change in level. Cost was just under £100,000. Later renumbered as A4042 and unclassified south of the Usk Way junction.
|Caerwent - Crick Dualling
|Reported as being constructed in the Western Mail of 10 January 1938. 0.75 mile with cycle tracks and footpaths. Estimated cost £20,146. Construction may have run on into 1939.
|Briton Ferry Bridge
|The dual carriageway crossing of the Neath River and Briton Ferry Docks was opened on 31 October 1955 by John Boyd-Carpenter, Minister of Transport. It also included cycle tracks and footpaths. The river viaduct was almost 2000 foot long with 17 spans and the dock viaduct was 972 foot long with 11 spans, with a cutting through Warren Hill in between. Cost £2 million. It was the largest river bridge then built in Britain since WW2. Neath Bypass stage 1, it shortened the route to Swansea by 6 miles.
|The almost 2 mile road from Melin llan Bridge to Swansea County Borough Boundary was completed in the year to 31 March 1957 per the 1956-57 Roads in England and Wales Report. It may have opened in 1956. 60 foot wide with a 30 foot carriageway and 6 foot footpath.
|Stage 2. The 2.5 mile dual carriageway from Earlswood, Briton Ferry Bridge to Lon-las (west of Neath) was opened on 17 November 1959 by Major C.G. Traherne, Lord Lieutenant of Glamorgan. Contractor was Cleveland Bridge Company who, in their opening day advert, described it as through a mountain and two hills, across two swamps, six railway lines, two main roads, a canal and tidal creek and completed some months early. Not mentioned was chopping into the cellar of the Vernon Arms during bridge works. It had twin 22 foot carriageways with 8 foot central reservation and footpaths. Cost £1.7 million. Later upgraded as part of M4 J42 - J44.
|Stormy Down dualling
|The dual carriageway from Heol y Splot, Stormy Down to A4106 Bridgend Road roundabout, west of Laleston was completed in 1960 per the Wales and Monmouthshire Report of Developments and Government Action 1960. It had opened by May 1960. Online apart from a new deviation at the east end.
|The online dual carriageway from the Briton Ferry Bridge (A474) roundabout to the Baglan roundabout, at the west end of the future A48(M) Port Talbot Bypass, was opened in 1961 per the Wales and Monmouthshire Report of Developments and Government Action 1961.
|Newport: George Street Bridge
|The 1,765 foot bridge over River Usk was opened on 9 April 1964. It was the first cable cantilever bridge in U.K.. It used 13,850 feet of galvanised locked coil wire rope from British Ropes' factories in Doncaster. The 3 inch wire rope passed through the 165 foot high hollow concrete towers to the anchor spans. Contractor was Cleveland Bridge and Engineering of Darlington. Later downgraded to B4237. The adjacent dualling of George Street and Wharf Road was not shown on the 1967 OS One inch map but was shown on the 1968 OS Quarter inch map.
|Section B: Coracle Way. The 0.17 mile bypass of The Quay was opened on 1 January 1965 per the Wales 1965 Report. Later renumbered A4212.
|The 2.5 mile road was opened on 27 September 1965 by Councillor and Mrs Glyn McNeil, Mayor and Mayoress of Cowbridge. It had 24 foot dual carriageways within an 88 foot width, and a 15 span 1,500 foot long viaduct over the Thaw valley at a height of between 20 and 45 feet. Contractor was Sir Robert McAlpine and Sons (South Wales) Ltd., cost £1.4 million.
|Cardiff: Newport Road Improvement
|The reconstruction to D3 dual carriageway of the 0.46 mile between Fitzalan Place and Piercefield Place was completed in 1965 per the Wales 1965 Report. Cost £240,000. Later renumbered A4161.
|1965 - 1966
|Sandford Bridge (Alvington) Diversion
|Tenders for kerbing were invited in June 1965.
|Groes Dualling (Margam)
|0.45 mile dualling eastwards from Groes Roundabout, the eastern end of the A48(M) (Port Talbot Bypass) which opened on 22 July 1966. The dual carriageway is shown on the OS Quarter inch maps and would have been built along with the motorway. It may have opened earlier. The dualling was extended later from the Ty'n-y-caeau farm entrance to M4 J38 Margam Interchange.
|1966 - 1967
|Brookend (Alvington) Dualling
|Shown on December 1967 OS One inch map, not on September 1966 edition (although only a partial revision).
|Cardiff: Eastern Avenue
|The 6 mile dual carriageway from Gabalfa Interchange to St Mellons Roundabout was opened on 19 November 1971 by Queen Elizabeth II. Cost £4 million.
|Chepstow Inner Relief Road
|Stage 1: Mount Pleasant to Station Road was opened on 2 March 1973. Contractor was Haywood Group of Chepstow, cost £140,000.
|Port Talbot Inner Bypass
|Heilbronn Way. The section from Pentyla Roundabout to the roundabout by Port Talbot Parkway Railway Station (Station Road) was opened on 28 May 1976 per the Land Compensation Act Notice.
|Penllergaer Interchange Diversion
|M4 J47 was opened on 29 April 1977 as part of the Pontarddulais Bypass. The A48 Diversion would have opened earlier.
|Ty'rheol Diversion (south of Pontlliu)
|Expected to be in connection with the M4 construction which opened in 1977.
|Carmarthen Southern Bypass
|The 3 mile dual carriageway from Pont Lesneven roundabout, Johnstown to Nant-y-caws was opened on 22 July 1983 (Nicholas Edwards, Welsh Secretary was to open it). Part was A40. Contractor was Sir Alfred McAlpine and Son (Southern) Ltd., cost £16.7 million.
|Llanddarog and Cross Hands Bypass
|Also bypass of Porthyrhyd and Drefach. The 7.5 mile dual carriageway was opened on 22 July 1987 by Wyn Roberts, Minister of State for Wales. Contractor was a Thyssen-Taywood joint venture, cost £20 million.
|Chepstow Inner Relief Road
|Stage 2: The 1 mile S2 road from Station Road to Gloucester Road was completed in January 1988 (per the Trunk Roads, England, into the 1990's Report), to complete the relief road. Outturn works cost £8 million. The viaduct section, Chepstow New Bridge, was reported as opened by Wyn Roberts, Minister of State for Wales in the Gloucester News of 4 February 1988.
|Nant-y-Caws to Coed Hirion Bypass
|The 3.4 mile dual carriageway from the foot of Nant-y-Caws hill (west of the village) to west of Llanddarog was completed on 16 August 1990 per the Noise Insulation Regulations notice. An official opening by Wyn Roberts, Secretary State for Wales, was reported in the 4 October 1990 Llanelli Star. The eastern section was online, with a new westbound carriageway. It completed the dual carriagway from west of St Clears to M4 at Pont Abraham. Contractor was A. Monk Building and Civil Engineers Ltd., contract price £7.6 million.
|Stage 1: The western end between High Street and Church Road (B4231) was opened on 22 September 1992 by Maggie Levett. MP for Ashchurch and Twyning. Cost £1.1 million. It is unclear if it opened with a different number or as a spur of A48.
|Mentioned in a Western Daily Mail report of 28 Feb 1996. Albany Bridge Plaque shows a date of 1995. Garage adverts in September 1995 mentioned the bypass. The first stage at the western end had opened in 1992.
|Newport Southern Distributor Road
|Pont Ebbw Roundabout, Cardiff Road to M4 J24 Coldra Interchange. The 187m steel tied arch City Bridge over River Usk opened on 17 November 2004. The final section of the road was due to open in the next week. The first section to open had been Ringland Way in August 2003. Contractor was Mogan Vinci. Scheme cost £55 million. It was the then largest Private Finance Initiative in Wales.
The dates of the following have not yet been determined:
Claxhill Bypass - Shown on the 1936 OS Six inch map.
Newport: Cardiff Road dualling - after 1983 OS 1:50000 map.
Cardiff City: Newport Road dualling - Between the 1965 and 1969 OS One inch maps.
Bancymansel Diversion (north of Drefach) - Between the 1966 and 1972 OS One inch maps (now B4310).
Rhos Mary Diversion - Between the 1960 and 1966 OS One inch maps.
[[Category:Welsh Government | subauthority = South Wales TRA]]