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.

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