M4 Junction 15: Plough Hill Interchange (A346, A419)

Map of M4 Junction 15: Plough Hill Interchange — M4 Junction 15: Plough Hill Interchange. Map data © OpenStreetMap contributors. Map drawing © Corporate Ace Limited.

Junction 15 is the main turn for Swindon, about three and a half miles north-west, on the A419 and the A346, with the A419 continuing to Cirencester. Chiseldon, Liddington and Badbury Park are close by. Coate Water Country Park is about a mile north-west.

Swindon's south and east sides, Marlborough and Cirencester all depend on Junction 15. Whether you are commuting to Swindon, delivering there or visiting for the first time, this page shows what is around it and how often things have gone wrong.

Check this junction now: live M4 speed flow map · latest M4 traffic news · M4 serious incidents · M4 accidents

M4 Junction 15 Now: Accidents, Incidents and Roadworks

Live traffic news at M4 Junction 15

Incidents and roadworks between Junction 14 and Junction 16 that we are aware of.

M4 both directions Jct 16 to Jct 17 - lane 3 closure

Active nowUpdateBoth directions

Time now: Wednesday, 21 October 2026, 21:29 (9:29pm)

21:28 (9:28pm)21 Oct 2026reported just now

Location: M4 eastbound between J17 and J16
Direction: Both directions
Lanes closed: Lane closures
Reason: Repair work
Schedule: 20:53 (8:53pm) Wed 21 Oct 2026 → 06:00 (6am) Thu 22 Oct 2026

⏳Expected to clear in ~8h 30m HA planned end: 06:00 (6am) Thu 22 Oct 2026

+ 7 more near Junction 15 - see all the M4 traffic news →

This is the news for Junction 15 only, not the whole M4. For the rest of the motorway see all the latest M4 traffic news, the overhead signs and the speed limits in force now.

Updated 21:29 (9:29pm) Wed 21 Oct 2026

Live Traffic Speeds at M4 Junction 15

The speed strip below shows the M4 around this junction, both directions, from National Highways’ live data, checked every five minutes.

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60 mph +50–5930–4915–29under 15

closedM62connecting motorwayA6A road👈M1our site: tap for its map

services, on the side you can reach them

crashincidentqueueroadworksspeed limitspeed shown on the signsstop-startoverhead sign

reported by drivers, which can’t always be relied onconfirmed by National Highways

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Go to our live M4 traffic speed flow map ›

In an emergency call 999. To report a problem on a motorway, call National Highways on 0300 123 5000 (24 hours).

NOTE: The speed flow, overhead sign messages or other information shown on our live traffic speed flow map is updated every few minutes. We cross check the data and aim to provide warnings if there could be a delay or an inaccurate speed reading. There can be occasions, beyond our control, and despite our best efforts where the speed flow could be inaccurate. We cannot therefore guarantee the speed you can expect on any stretch of the motorway is always accurately shown. However we hope you will find our live traffic speed flow map a useful tool in trying to plan your journey. Safe driving.

All the latest M4 traffic news →Live M4 traffic speed flow map →

M4 J15 in Our Records

Incidents here, last 13 days105 collisions, 5 breakdowns or obstructions

Typical time to clear48 minutesthe middle value of 10 cleared

Slowest daytime hour westbound06:00–07:00average 63 mph (typical 62 mph)

Slowest daytime hour eastbound17:00–18:00average 64 mph (typical 65 mph)

Half of the incidents we recorded at J15 were collisions (5 of 10). In both directions, traffic usually keeps close to its typical speed through the day.

Average speed by hour of day at J15

our average, last 13 daysNational Highways’ typical speed

Westbound

Eastbound

Incidents per week at J15

collisionsbreakdowns and obstructions* part week: we started recording during it

The latest 5 here

Mon 19 Oct, 12:49 (12:49pm) Overturned Vehicle ✓Reported by National Highways
M4 eastbound between junctions J15 and J14
✓ Cleared after about 79 minutes (1.32 hours)
Mon 19 Oct, 11:53 (11:53am) Tyre Change ✓Reported by National Highways
M4 westbound between junctions J14 and J15
✓ Cleared after about 23 minutes
Sun 18 Oct, 15:55 (3:55pm) Collision ✓Reported by National Highways
M4 eastbound between junctions J16 and J15
✓ Cleared after about 24 minutes
Sat 17 Oct, 02:54 (2:54am) Collision ✓Reported by National Highways
M4 westbound between junctions J14 and J15
✓ Cleared after about 48 minutes
Fri 16 Oct, 21:22 (9:22pm) Vehicle Fire ✓Reported by National Highways
M4 westbound between junctions J14 and J15
✓ Cleared after about 149 minutes (2.48 hours)

Built from our own records of National Highways’ live data for the M4 either side of J15: speeds from 13 days of five-minute readings, incidents from the last 13 days (we started recording incidents on 09/10/2026). Each incident is counted once. Updated every five minutes.

Junction M4 J15, Plough Hill Interchange
Roads at this junction A346, A419
Nearest town Swindon, 3.5 miles north-west
Junction before J14, Wickham Interchange, about 11.6 miles in a straight line
Junction after J16, Spittleborough, about 5.7 miles in a straight line

Around M4 Junction 15: Plough Hill Interchange: Towns and Places on the Map

Map of the area within about 5 miles of M4 Junction 15: Plough Hill Interchange, showing the towns, villages, roads and places to visit — The area within about 5 miles of M4 Junction 15. Map data © OpenStreetMap contributors. Map drawing © Corporate Ace Limited.

Places on the Map Near M4 Junction 15
Place	What it is	From the junction
Coate Water Country Park	Park or nature reserve	About 1 mile north-west
Richard Jefferies Museum	Attraction	About 1.5 miles north-west
Mannington Retail Park	Shopping	About 4 miles north-west