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Latest live M4 traffic news

Live M4 traffic news and updates for M4 junctions, plus real time travel reports on delays, accidents, roadworks and snow

Diesel motorway pollution smog traffic

The M4 is the main road running between London and South Wales, passing via Slough, Reading, Swindon, Bristol, Newport, Cardiff and Swansea along the way. Much like the rest of the UK’s road network, the M4 has its areas most likely to cause tail backs – primarily where it joins the M25 on the west of London and also where it meets the M5 near Bristol. Naturally, accidents, roadworks and other traffic issues cause delays, so it pays to be on top of your journey before you start your engine.

Where the M4 crosses the River Severn at the Welsh end of the motorway, it uses a toll bridge – which is one of only three left in the UK. The tolls are only charged when driving in a westerly direction, meaning drivers are charged to enter Wales, but not to enter England. The original River Severn crossing (the M4 uses the second one built) now carries the M48. 

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Generally the majority of the M4 tends to stay relatively clear, but the 189-mile route can see extra congestion during rush hour and summer holidays. If you’re planning to use any section of the M4 motorway, this page will be a useful aid for travel alerts, live updates and an incident map for both westbound and eastbound lanes.

Tweets

Scroll down to find live tweets from the Highways Agency, official police accounts and other traffic news feeds.

M4 live traffic map

If there is traffic disruption on the M4 you can keep up to date on any delays with our live and continuously updated M4 traffic map.

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The map below shows live updates on the current disrupted areas of the M4 for roadworks, accidents or general congestion causing delays on the route…

M4 weather report

Details of the latest weather warnings in the M5 area from the Met Office...

Met Office South West weather report

The history of the M4 

The Ministry of Transport first proposed a new road from London to South Wales in the 1930s. Plans for the M4 as one of the first major post-war trunk roads were produced in 1956 and construction began in 1961. The Chiswick flyover, a short section of elevated dual-carriageway built to reduce the impact of traffic travelling between central London and the west, opened in 1959 and later became part of the new M4 route. The section from J18 to the west of Newport was opened in 1966, including the Severn Bridge, which is now part of the M48.

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The English section of the motorway was completed in December 1971 when the 50-mile stretch between Maidenhead and Swindon was opened for public use. The Welsh section was finished in 1993, when the Briton Ferry bridge opened. The Second Severn Crossing opened in 1996, and motorways on either side of the river carried the M4 over the new crossing when construction was finally completed. 

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• M5 traffic: live news updates

M4 junctions

All of the M4 junctions on the southbound and northbound carriageways are detailed below... 

Eastbound exits (B carriageway)JunctionWestbound exits (A carriageway)
Road continues as A4 to Central LondonJ1Start of motorway
North Circular A406

South Circular A205

Chiswick A315

J2Staines, Hounslow, Brentford A4
Heston servicesServicesHeston services
Heathrow  (Terminals 4, 5 & Cargo), Hayes, Harrow, Hounslow A312J3Heathrow  (Terminals 4, 5 & Cargo), Hayes, Harrow, Hounslow A312
Heathrow  (Terminals 1, 2 & 3) (A4)

Uxbridge A408

J4aHeathrow  (Terminals 1, 2 & 3) (A4)

Uxbridge A408

Heathrow (Terminals 4, 5 & Cargo) , Gatwick Airport , Watford (M3), (M23), (M40), (M1) M25J4bHeathrow (Terminals 4, 5&Cargo), Gatwick, Watford (M3), (M23), (M40), (M1), M25
Colnbrook, Langley, Slough (East) A4

Eton, Datchet B470

J5Colnbrook, Langley, Slough (East) A4, Datchet B470
Slough (Central) A355

Windsor A322

J6Slough (Central) A355

Windsor A322

Slough (West) A4J7Slough (West) A4
High Wycombe, Henley A404(M)

Maidenhead A308(M)

J8/9High Wycombe, Henley A404(M)

Maidenhead A308(M)

Reading (East), Wokingham, Bracknell A329(M)J10Reading (East), Wokingham, Bracknell A329(M)
Basingstoke, Reading (Central & South) A33J11Basingstoke, Reading (Central & South) A33
Reading servicesServicesReading services
Reading (West), Theale A4J12Reading (West), Theale A4
Newbury, Oxford A34

Chieveley services (Moto)

J13

Services

 

Newbury, Oxford A34

Chieveley services (Moto)

Hungerford, Wantage A338J14Hungerford, Wantage A338
Membury servicesServicesMembury services
Swindon (East) A419

Marlborough A346

Oxford (A420)

J15Swindon A419, Marlborough A346
Swindon (West), Royal Wootton Bassett, Wroughton, RAF Lyneham, Calne A3102J16Swindon (West), Royal Wootton Bassett, Wroughton, RAF Lyneham, Calne A3102
Chippenham A350

Cirencester A429

J17Chippenham A350

Cirencester A429

Leigh Delamere servicesServicesLeigh Delamere services
Bath, Stroud A46J18Bath, Stroud A46
Bristol M32J19Bristol M32
The SOUTH WEST, Bristol (West), The MIDLANDS, Gloucester M5J20

Almondsbury Interchange

The SOUTH WEST, Bristol (West) M5(S)

The MIDLANDS, Gloucester M5(N)

No accessJ21Chepstow M48
Avonmouth M49J22Avonmouth M49
Entry into EnglandSecond Severn CrossingEntry into Wales
No toll plazaBridge TollToll plaza
Chepstow M48J23No access
Magor, Caldicot A4810

Magor services

J23A

Services

Magor, Caldicot A4810

Magor services

City centre A48

Newport (East) B4237

Monmouth A449

The MIDLANDS (M50)

J24City centre A48

Newport (East) B4237

Monmouth A449

No accessJ25Caerleon B4596
No accessJ25ANewport, Cwmbran A4042
Brynglas TunnelsTunnelBrynglas Tunnels
Newport, Cwmbran, Caerleon A4051J26Newport A4051
High Cross B4591J27High Cross B4591
Newport A48

Risca, Brynmawr A467

J28Newport A48

Risca, Brynmawr A467

No accessJ29Cardiff (East and South) A48(M)
Cardiff (East) A4232

Cardiff Gate services

J30

Services

Cardiff (East) A4232

Cardiff Gate services

Merthyr Tydfil, Cardiff A470J32Cardiff (North), Merthyr Tydfil A470
Cardiff (West), Barry, Penarth A4232

Cardiff Airport

Cardiff West services

J33

Services

Cardiff (West), Barry, Penarth A4232

Cardiff Airport

Cardiff West services

Llantrisant, Rhondda A4119

Royal Glamorgan Hospital

J34Llantrisant, Rhondda A4119

Royal Glamorgan Hospital

Pen-coed A473J35Bridgend, Pen-coed A473
Bridgend A4061

Maesteg A4063

Princess of Wales Hospital

Sarn Park services

J36

Services

Bridgend A4061

Maesteg A4063

Princess of Wales Hospital

Sarn Park services

Pyle, Porthcawl A4229J37Porthcawl, Pyle A4229
Port Talbot A48J38Port Talbot A48
No access (on-ramp only)J39No access
Port Talbot A4107J40Port Talbot A4107
Port Talbot A48J41Briton Ferry A48
Briton Ferry A48

Swansea (South) A483

J42Swansea (South) A483
Neath, Merthyr Tydfil A465J43Neath, Merthyr Tydfil A465
Swansea (East) A48J44Swansea (East) A48
Pontardawe, Swansea (North) A4067J45Pontardawe, Swansea (North) A4067
Llangyfelach B4489

Felindre

Morriston Hospital

J46Llangyfelach B4489

Felindre

Morriston Hospital

Swansea (West) A483

Gorseinon A48

Swansea services

J47

Services

Swansea (West) A483

Gorseinon A48

Swansea services

Pontarddulais, Llanelli A4138J48Pontarddulais, Llanelli A4138
Start of motorwayJ49

Terminus

Services

Motorway terminates at a roundabout:

Carmarthen A48

Ammanford, Llandeilo A483

Pontarddulais A48

Pont Abraham services

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