M3 Junctions 12 to 14 (Eastleigh, Chilworth & the M27)
The southern end of the M3 runs from Junction 12 at Eastleigh, through Junction 13 at Chilworth, to Junction 14 where the motorway ends at the M27 outside Southampton. This is the busiest part of the M3 by a clear margin.
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Latest accident or incident on the M3
The most recent accident or incident on the M3 that we are aware of.
M3 Eastbound Jct 2 to Jct 1 carriageway closure
00:462 Sept 2026reported 10 min ago
- Location
- M3 eastbound between J2 and J1
- Direction
- Eastbound
- Lanes closed
- Carriageway closed
- Reason
- Other
- Schedule
- 22:00 Tue 1 Sept → 05:30 Wed 2 Sept
Latest active roadworks on the M3
Roadworks live on the M3 right now.
A303 eastbound crematorium to M3 carriageway closure
00:462 Sept 2026reported 10 min ago
- Location
- M3 eastbound between J8 and J7
- Direction
- Eastbound
- Lanes closed
- Carriageway closed
- Reason
- Roadworks
- Schedule
- 20:54 Tue 1 Sept → 06:00 Wed 2 Sept
+ 1 more active roadworks - search all M3 traffic news →
Latest planned roadworks on the M3
The next planned roadworks scheduled on the M3.
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Updated 00:57 Wed 2 Sept
Powered by National Highways’ Transport Data Feeds.
The busiest stretch of the M3
All three of these stretches are physically counted by the Department for Transport. These are the 2025 figures.
| Stretch | Length | Vehicles per day | Lorries | Vans |
|---|---|---|---|---|
| J11 Compton to J12 Eastleigh | 3.5 miles | 128,023 | 9,384 | 21,473 |
| J12 Eastleigh to J13 Chilworth | 1.7 miles | 130,785 | 9,893 | 21,734 |
| J13 Chilworth to J14 and the M27 | 1.2 miles | 140,750 | 9,901 | 23,683 |
The final 1.2 miles into the M27 is the busiest measured stretch of the entire M3 — 140,750 vehicles a day, or about 98 every minute, day and night, averaged across the year.
It is also the most van-heavy part of the motorway: 23,683 LGVs a day, close to one vehicle in six. Add the lorries and better than one in five is a working vehicle.
Traffic builds steadily all the way down: 128,023 at Junction 12, 130,785 at Junction 13, 140,750 at Junction 14. Nothing gets quieter on the approach to Southampton.