A1(M) Junctions 1 to 10: Hertfordshire
This is the southern A1(M), 24.14 miles from the M25 at South Mimms to Stotfold, north of Baldock. It runs through Hatfield, Welwyn Garden City and Stevenage. Reports for this section are shown below.
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Latest accident or incident on the A1(M)
The most recent accident or incident on the A1(M) that we are aware of.
Latest active roadworks on the A1(M)
Roadworks live on the A1(M) right now.
A1m northbound Jct 36 entry slip road closure
03:2626 Sept 2026reported 6 min ago
- Location
- A1(M) J36 northbound access
- Direction
- Northbound
- Lanes closed
- Carriageway closed
- Reason
- Maintenance work
- Schedule
- 20:00 Fri 25 Sept 2026 → 06:00 Sat 26 Sept 2026
Latest planned roadworks on the A1(M)
The next planned roadworks scheduled on the A1(M).
A1M Jct 63 to Jct 62 Southbound Lane 1 Closure (2)
03:2626 Sept 2026reported 6 min ago
- Location
- A1(M) southbound between J63 and J62
- Direction
- Southbound
- Lanes closed
- Lane closures
- Reason
- Road improvement or upgrading
- Schedule
- 20:00 Fri 25 Sept 2026 → 06:00 Sat 26 Sept 2026
Forecast - not confirmed
+ 15 more planned roadworks - search all A1(M) traffic news →
Search all the latest A1(M) traffic news →
Updated 03:32 Sat 26 Sept 2026
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The junctions on this section
- Junction 1 — the M25 at its Junction 23, and South Mimms services.
- Junctions 2 and 3 — the A1001 and A414 for Welham Green, Hatfield and St Albans.
- Junction 4 — the A414 for Hertford and the A6129 for Welwyn Garden City. The Hatfield Tunnel lies between Junctions 3 and 4.
- Junctions 5 and 6 — the A1000 for Welwyn Garden City and Welwyn. Junction 5 is a part junction, with no slip roads southbound and only an entry slip northbound.
- Junctions 7 and 8 — the A602 for Stevenage, Ware and Hitchin.
- Junction 9 — the A505 for Letchworth and Baldock, and the route towards Luton Airport.
- Junction 10 — the A507 for Baldock, Stotfold and Shefford, with Baldock services. The motorway ends here and the road continues north as the A1.
The Hatfield Tunnel
Between Junctions 3 and 4 the A1(M) passes through the Hatfield Tunnel, 1,150 metres long and built between 1983 and 1986. The Junctions 2 to 4 stretch was the last of this section to open, in 1986. The oldest part, Junctions 6 to 8 past Stevenage, opened in 1962.
How busy is this section?
| Stretch | All vehicles | Lorries | Share lorries |
|---|---|---|---|
| A1 to the M25 at J1 | 49,183 | 1,935 | 3.9% |
| J1 to J2 | 73,025 | 3,836 | 5.3% |
| J2 to J3 | 59,066 | 3,564 | 6.0% |
| J3 to J4 | 90,181 | 4,661 | 5.2% |
| J4 to J5 | 84,148 | 4,130 | 4.9% |
| J5 to J6 | 73,375 | 3,591 | 4.9% |
| J6 to J7 | 83,782 | 4,285 | 5.1% |
| J7 to J8 | 71,265 | 4,043 | 5.7% |
| J8 to J9 | 93,845 | 4,818 | 5.1% |
| J9 to J10 | 49,176 | 3,399 | 6.9% |
Between Junctions 6 and 7 a second count point at Junction 6 records 81,289, and near Junction 10 another records 35,262; we show the busier figure for each stretch. Traffic nearly halves after Junction 9 as drivers leave for Letchworth, Baldock and the A505.
Beyond this section
North of Junction 10 the road is the A1 until Alconbury; see A1 traffic news. The next motorway section is Junctions 14 to 17, Peterborough. For the M25, see M25 Traffic; for the M1 to the west, see M1 Traffic. All sections: A1(M) maps.
Traffic count figures on this page are from the Department for Transport road traffic statistics, 2025.