|From:||Trostre, Llanelli (SN525000)|
|Distance:||5 miles (8 km)|
|Meets:||A484, B4297, B4303, M4, B4306, A48|
|Old route now:||B4297|
|Route outline (key)|
The A4138 is a short road in south Carmarthenshire.
The route starts at a roundabout on the non-primary A484 in the Trostre retail park, to the east of Llanelli town centre. It heads north as primary D2, which narrows to S2 after the B4297 is met at traffic lights. There's a roundabout for the next B-road, the B4303, after which the road enters open country. It heads roughly northeastwards, with the occasional roundabout serving unclassified roads – the only junctions on this part of the route.
After passing to the north of Llangennech another set of traffic lights is met – a second junction with the B4297 – and our road now descends to meet the M4 at J48. This is a diamond interchange and traffic on the A4138 has a straight line through, passing under the M4 before reaching traffic lights controlling the junctions with the slips from and to the motorway's eastbound carriageway.
The route loses its primary status here and continues north-east along a residential road through Hendy. The B4306 is met at a triangular junction on the village green, after which the road crosses the River Gwili. It continues through the village along Iscoed Road, ending at a mini-roundabout at the far end on the A48 west of Pontarddulais.
The A4138 came into existence around 1930 when the B4302 was upgraded to Class I status. That road ran between the A48 (present B4297 with many years as the A484) near Llanelli and the A475 (renumbered A48 in 1935) in Pontarddulais along a more easterly course than the current A4138, via the centre of Llangennech.
Following construction of the M4 in 1977 the majority of the existing route of the A4138 was bypassed and the remainder upgraded, so as to serve Llanelli better from the new motorway. The old road through Llangennech became the B4297. The northernmost section into Pontarddulais was not upgraded and retains its original atmosphere.