Pentyla Interchange

Pentyla Interchange is junction 41 of the M4. It is the only junction where you can join the motorway network and leave it at the same junction.

A multi-span viaduct was required to avoid building large abutments close to the railway. Large mobile cranes lifted the beams while the railway was closed. Due to the sharp bend, a high containment (P6) parapet was provided, the first of its type.

The roundabout was called Sunnycroft Roundabout, and had traffic lights added from 19 December 1989.

Routes

Fork

Route	To	Notes
M4	Swansea/Abertawe	access only to/from M4
M4	Cardiff/Caerdydd
A48	Swansea/Abertawe, Carmarthen/Caerfyrddin (M4)
A48	Baglan, Port Talbot
A4241	Sandfields, Baglan Energy Park/Parc Ynni Baglan, Baglan Ind Park/Parc Ddiw Baglan, Aberavon	formerly B4286
A48(M)	Cardiff/Caerdydd	fork junction didn't exist, motorway mainline went to roundabout

Half-diamond

Route	To	Notes
M4	Swansea|Abertawe
M4	Cardiff/Caerdydd, Bridgend/Pen-y-bont	access only to/from M4
A48	Baglan
A48	Cardiff/Caerdydd, Town Centre/Canol y Dref, Hospital, Margam, Parkway Station
B4286	Velindre, Cwmavon/Cwmafon, Pontrhydyfen, Civic Centre/Canolfan Ddinesig
	Multi storey car park/Parc ceir aml-lawr
A48(M)	Swansea/Abertawe
A48(M)	Cardiff/Caerdydd, Bridgend/Pen-y-bont	access only to/from A48(M)

Links

legislation.gov.uk

• The M4 Motorway (Junction 41, Westbound Exit Slip Road, Sunnycroft Roundabout, Baglan, Neath Port Talbot) (50 MPH Speed Limit) Regulations 2010