National Highways will close the M3 Junction 9 roundabout from 9pm on Friday, 11 September until 6am on Monday, 14 September to complete road connections to the new roundabout and bridges being built at the interchange.
The M3 itself will remain open through Junction 9 in both directions. However, all entry and exit slip roads at the junction will be closed, preventing traffic from joining or leaving the motorway there during the closure.
The disruption will extend well beyond the roundabout itself. The A34 southbound will be closed from Bullington Cross to M3 Junction 9, while the A34 northbound will be closed towards Three Maids Hill, including the A33 northbound connection.
The A33 southbound will also close from the Cart and Horses junction, Easton Lane will be shut in both directions at Easton Lane Roundabout, and the A272 will be closed in both directions from the Spitfire roundabout on the A31.
National Highways has published separate diversion routes for traffic travelling between the M3, A34, A33, A272, Easton Lane and Winchester.
For hauliers, the closure is particularly relevant because Junction 9 links the M3 with the A34, a major north-south freight corridor connecting the south coast with the Midlands.
Drivers should also be aware that the M3 Junction 9 northbound entry slip road is already under a long-term closure until winter 2027, meaning there is no direct access to the northbound M3 from the roundabout even outside this weekend’s works.
Further disruption will follow immediately after the weekend closure. From Monday, 14 September until late November, Easton Lane westbound towards Tesco will be reduced to one lane while work continues on the embankment and old southwest subway.
National Highways advises drivers to follow the signed diversion routes and warns that planned closures can change at short notice.
More on UK motorway closures and roadworks:
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