Major overhaul planned for Llanelli’s Halfway lights as council sets out sweeping junction redesign

The A4138 is the main route between the M4 at Junction 48 in Hendy and Llanelli, carrying thousands of vehicles a day into the town. The Halfway lights sit right in the middle of that corridor — and the council says the layout has become a major choke point.

The authority has now published early designs for a full overhaul of the A4138 Halfway Traffic Signals, the crossroads linking the main road with Glyncoed Terrace, Llandafen Road and the Pemberton Retail Park. The junction is widely seen as one of the area’s worst pinch points, with long queues building in both directions during peak hours.

Vehicles queue at the A4138 Halfway junction in Llanelli, a key route linking the town to the M4 at Hendy.
(Image: Google Maps)Drivers wait at the Halfway lights on the A4138 in Llanelli, where congestion and delays are common during peak hours.
(Image: Google Maps)

Road widening, new bus gate and redesigned signals

According to the council, the A4138 southbound would be widened to create a longer right‑turn lane into Llandafen Road — a move officials say would ease the regular tailbacks outside Morrisons and the retail park.

A new bus lane and bus gate is also proposed on the Parc Pemberton exit road. The council says this would give buses priority leaving the retail park, though the impact on general traffic has not yet been publicly detailed.

The junction itself would be reshaped, with kerbline changes, traffic island alterations and a revised signal layout designed to increase capacity and shorten waiting times.

Artist’s impression of the proposed redesign at the A4138 Halfway junction, showing widened lanes, new crossings and Active Travel links.
(Image: AtkinsRealis)Illustration of the planned shared-use path and bus gate at the Halfway junction, part of wider Active Travel improvements.
(Image: AtkinsRealis)Map showing the proposed redesign of the A4138 Halfway junction in Llanelli, including road widening, new crossings and Active Travel connections.
(Image: AtkinsRealis)

New crossing and Active Travel link

One of the most visible changes would be a new controlled pedestrian crossing on Glyncoed Terrace, along with the removal and relocation of several guardrails, signal poles and lighting columns.

A new shared‑use walking and cycling path is also planned along the A4138 southbound, creating a direct link into the wider Llanelli Active Travel Spinal Route. That includes the recently opened Phil Bennett Active Travel bridge, now a key crossing point on the town’s growing walking and cycling network. The council says the Halfway junction upgrade is intended to “tie in” with that route and finally close a long‑identified gap in the area’s Active Travel connections.

Smart sensors already tracking traffic

Engineers from AtkinsRéalis, who have been appointed to design the scheme, are using data from smart traffic sensors installed at the junction since June 2024. The sensors track vehicle movements and pedestrian activity, giving designers a real‑time picture of how the junction currently behaves.

The council says the modelling shows how the extended right‑turn lane and revised signal timings could reduce delays at peak times, though full modelling results have not yet been published.

Traffic flow diagram showing vehicle movements at the A4138 Halfway junction, based on VivaCity sensor data from April 2025.
(Image: AtkinsRealis)

Design work due to begin within months

The council says detailed design work is expected to begin later this year. Construction would depend on funding approval from the Welsh Government and the South West Wales Corporate Joint Committee.

Officials describe the upgrade as necessary to tackle congestion, improve safety and modernise the junction, though the final design and timeline remain subject to funding and public feedback.

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