The A4119 through Talbot Green was first built circa 1977 [citation needed] as a single carriageway passing to the side of the village straight on to Ely Valley Road, easing pressure off the original small lanes that lead from Talbot Green to the area known as Mwyndy, south of the village.

[citation needed] The completed "Talbot Green to Ynysmaerdy Dual Carriageway" officially opened on 28 July 1995.

[citation needed] The scheme replaced the old Roundabout near Llantrisant with a four way traffic-lit junction, and completely replaced the original Ely Valley Road at Talbot Green apart from the first portion: a t-junction from the centre Talbot Green's high street that leads to a row of houses and a Golf Club, this is the only remaining section Ely Valley Road that is un-altered, still bearing the original road surface and signage, [citation needed] although it is now a Cul-de-sac.

At the next roundabout the road takes the shape of a bow passed the Ely Meadows which is now the site of Magden Park, a development of Offices, Hotel, Pub and private Health facility.

[1] Bypassing the Royal Glamorgan Hospital, Avionics department of British Airways and the Headquarters of the Welsh Blood Service.

On the south-bound carriageway is a long stretch of original road, although now a parking area where refreshment vans and sleepy truckers are a common sight, it provides access to some houses and a rural lane leading to Llantrisant.

[citation needed] In August 2022, construction started on here to upgrade the section between the Ynysmaerdy and Coedely roundabouts to the dual carriageway and is expected to be completed in late 2024/early 2025.

The bypass, completed in 1987, takes the route of the old Ely Valley Railway, and the former site of the Coed-Ely Colliery is on the left.