The initial target cost under the early contractor involvement contract to upgrade the junction at Tredgar is set at £10.5m.

The complex upgrade, which was originally expected to cost around £25m, would see construction of an elongated gyratory to the south of the M4 with a dedicated through link for eastbound traffic from the M4 and A48.

The improvement to Junction 28 retains the M4 underbridges but requires the demolition of the M4 westbound on-slip underbridge over the A48 eastbound.

Existing junction layout

Planned new layout

There will also be improvement to nearby roundabouts at Bassaleg and Pont Ebbw roundabouts to help cut congestion.