Map of M4 Motorway Junctions
Map of the M4 motorway junctions.
West M4
To the West the M4 joins the M5 at M4 Junction 20 which heads north to Devon Cornwall and the South West of England.
The Western end of the M4 is in South Wales Junctions 23 to 48. Bridgend is on Junctions 25 to 37, M4 Junctions 44 and 45 for Swansea, Junctions 30 to 33 for Cardiff and Junctions 24 to 28 for Newport.
East M4
At the eastern end of the M4 is London, with Junctions for Slough, Reading, Newbury, Swindon and Bristol on the way to Wales in the West.
How Do I Find M4 Traffic News?
Simply type the search words in the search facility towards the top right of this page and click "search".
Search all the latest M4 traffic news
Latest accident or incident on the M4
The most recent accident or incident on the M4 that we are aware of.
Latest active roadworks on the M4
Roadworks live on the M4 right now.
M4 eastbound Jct 19 to Jct 18 hardshoulder or single lane running
01:27 (1:27am)12 Oct 2026reported 2 hr ago
- Location
- M4 eastbound between J19 and J18
- Direction
- Eastbound
- Lanes closed
- Hard shoulder closed
- Reason
- Roadworks
- Schedule
- 20:58 (8:58pm) Sun 11 Oct 2026 → 06:00 (6am) Mon 12 Oct 2026
+ 1 more active roadworks - search all M4 traffic news →
Latest planned roadworks on the M4
The next planned roadworks scheduled on the M4.
M4 eastbound Jct 18 to Jct 17 hardshoulder closure (166/2 to 161/4)
01:27 (1:27am)12 Oct 2026reported 2 hr ago
- Location
- M4 eastbound between J18 and J17
- Direction
- Eastbound
- Lanes closed
- Hard shoulder closed
- Reason
- Maintenance work
- Schedule
- 07:00 (7am) Mon 12 Oct 2026 → 18:00 (6pm) Mon 12 Oct 2026
Forecast - not confirmed
+ 8 more planned roadworks - search all M4 traffic news →
Road closed — on the overhead signs now
National Highways’ overhead signs are showing a road closure, as at 02:57 (2:57am) Mon 12 Oct 2026.
M4 J19-J20 CLOSED
Time now: Monday, 12 October 2026, 02:57 (2:57am)23:11 (11:11pm)11 Oct 2026set 4 hrs ago⚠ 4 hrs old✓ Checked by us 02:57 (2:57am)
M4 J19-J20
CLOSEDOverhead Message
WhereM4 westbound, J16 to J18 · on 8 signsAlso onM4 signs onlySinceOn the signs since at least 21:06 (9:06pm) Sun 11 Oct 2026We check these overhead signs at least every five minutes, but we can't guarantee a sign is still current if an incident or issue has been cleared and the sign has not been updated yet. Signs and news can each carry something the other does not - check both before you travel.
Search all the latest M4 traffic news
Updated 02:57 (2:57am) Mon 12 Oct 2026
Powered by National Highways’ Transport Data Feeds.
M4 junctions — west to east
▲ WEST South Wales & Pont Abraham
- J49A48/A483Pont Abraham — M4 ends (for Llanelli, Ammanford)
- Pont Abraham servicesat J49
- J48A4138Hendy, Llanelli, Pontarddulais
- J47A48Penllergaer, Gorseinon, Swansea (west)
- Swansea West servicesat J47
- J46A48Llangyfelach, Morriston
- J45A4067Ynystawe, Clydach, Swansea Valley
- J44A48/A48Llansamlet, Swansea (east)
- J43A465Llandarcy, Neath, Heads of the Valleys
- J42A483Earlswood, Briton Ferry
- J41A48Baglan, Port Talbot (west)
- J40A48Port Talbot, Aberavon
- J39A48Cwmavon (west-facing only)
- J38A48Margam, Kenfig
- J37A4229Pyle, Porthcawl, Cornelly
- J36A4061/A4063Sarn, Maesteg, Bridgend (north)
- Sarn Park servicesat J36
- J35A473Pencoed, Bridgend (east)
- J34A4119Miskin, Llantrisant, Talbot Green
- J33A4232Cardiff West, Capel Llanilltern
- Cardiff West servicesat J33
- J32A470Coryton, Cardiff (north), Merthyr Tydfil
- J30A4232Cardiff Gate, Pentwyn
- Cardiff Gate servicesat J30
- J29A48(M)Castleton — A48(M) for Cardiff (east)
- J28A48Newport (west), Tredegar Park
- J27B4591High Cross, Newport (Rogerstone)
- J26A4051Malpas, Newport (north)
- J25aA4042Newport (Brynglas)
- J25B4596Caerleon, Newport (east)
- J24A48Coldra, Newport (east), Chepstow (A48)
- J23aA4810Magor, Llanwern
- Magor servicesat J23a
- J23M48M48 — old Severn Bridge / Chepstow
- J22M49M49 — Avonmouth link to the M5
- J21M48/A403M48 & Severn crossings, Aust
- J20M5Almondsbury — M5 interchange (Midlands / South West)
- J19M32M32 — Bristol city centre
- J18A46Tormarton, Bath, Stroud
- Leigh Delamere servicesbetween J17 and J18
- J17A350Chippenham, Cirencester
- J16A3102Swindon (west), Wootton Bassett
- J15A419Swindon (east), Cirencester, Marlborough
- Membury servicesbetween J14 and J15
- J14A338Hungerford, Wantage, Great Shefford
- J13A34Chieveley, Newbury — A34 for Oxford / Southampton
- Chieveley servicesat J13
- J12A4Theale, Reading (west)
- Reading servicesbetween J11 and J12
- J11A33Reading (central), Basingstoke (A33)
- J10A329(M)Wokingham, Bracknell, Reading (east)
- J8/9A404(M)/A308(M)Maidenhead, High Wycombe, Marlow
- J7A4Slough (west), Huntercombe
- J6A355Slough (central), Windsor, Eton
- J5A4Langley, Slough (east), Datchet
- J4bM25M25 interchange (London orbital)
- J4A408Heathrow Airport, Uxbridge
- J3A312Hayes, Southall, Heathrow (A312)
- Heston servicesbetween J2 and J3
- J2A4Brentford, Chiswick (A4)
- J1A4/A406Chiswick — A4 & North Circular (London)
▼ EAST London & the A4 / North Circular
The M4 runs ~189 miles between London and South Wales, crossing the Severn. It meets the M25 (J4b), M32 (J19), M5 (J20), M48 (J21/J23) and M49 (J22). Tap Latest M4 Traffic News and search a junction for live updates.
Also travelling on the M25?
The M4 meets the M25 London orbital motorway at Junction 4b. If your journey also uses the M25, see our sister site M25 Traffic for the latest M25 traffic news and updates in the same easy-to-use format.