The M3 Junction 9 upgrade in Hampshire has reached its halfway stage, with National Highways preparing to demolish the existing gyratory bridges and progress the next phase of construction.
The project is reconfiguring the junction to enable the motorway to widen from two lanes to four beneath it, while creating new free-flowing links. A new roundabout above the motorway has been carrying traffic for several weeks after tie-in works were completed over the summer.
Two weekend closures
The M3 will be closed in both directions between junctions 8 and 9 from 9pm on Friday 23 October until 6am on Monday 26 October. The closure will allow the bridges on the northern side of the junction to be removed.
A second full closure is planned from 6 November to 9 November to enable demolition of the bridges on the southern side.
National Highways senior project manager Daniel Kittredge said: “We need to upgrade this junction to unlock its full potential as a key interchange for economic growth.
“Anyone driving through the area can see the great progress we’ve made already over the last 18 months, and this key milestone allows us to move on to the next phase of the project, where drivers will really see the new benefits start to take shape.”
He added: “To do that safely, this stretch of the motorway will be closed over two weekends and anyone travelling is advised to plan their journeys carefully and allow extra time where possible.”
New underpasses and walking routes
The scheme includes two 120m underpasses for the M3 and A34, new gyratory bridges, pedestrian pathways and a footbridge over the River Itchen. Kings Worthy Bridge will also be structurally widened.
National Highways expects peak-time journeys through the junction towards the A272 to be almost 30% faster. Drivers travelling between the M3 and A34 are expected to save more than 20% of their overall journey time during peak periods.
The upgrade is intended to support the construction of 2,000 new homes in Winchester. It will also provide more than 22 acres of chalk grassland and new routes for walkers, cyclists and horse riders.
VolkerFitzpatrick Balfour Beatty Joint Venture was appointed main contractor in December 2022, and construction formally began in April 2025. The programme has a budget of £290m.