National Highways’ upgrade of Junction 9 of the M3 in Hampshire gets under way this weekend and the organisation has reminded drivers that they may have to change the way they use the junction.

Part of its transformation includes reconfiguring the roundabout to allow for the motorway to be increased from two lanes to four as it passes under the junction. In order to do that, steel beams were installed earlier this year, and engineers have since been preparing the bridge deck surfaces and excavating the approaches that will connect to the new roundabout.

Now, a series of closures are needed so the project team can safely complete essential ‘tie-in’ works that cannot be carried out while traffic is using the roundabout.

This includes connecting new parts of the junction to the existing road network, with the new bridge on the north side of the roundabout and a new M3 southbound off slip both opening for the first time next week.

From 9pm on Friday 31 July, the roundabout, slip roads and several surrounding roads will all be closed until 6am on Monday 3 August, when the new bridge and off slip become operational.

The same applies for the weekends of 21–24 August and 11–14 September, though the main M3 carriageway will remain open throughout all three closures.

During each closure, stretches of the A34, A33, Easton Lane and A272 Spitfire Link will be closed.

The junction’s northbound entry slip road will stay closed from 9pm Friday 31 July all the way through until winter 2027.

Instead, drivers will be directed to join the M3 southbound at junction 9, travel to junction 11, then exit and re-enter the M3 northbound.

This is needed so the project team can safely build a new, dedicated A34 northbound link, which will provide a crucial route for freight travel from the ports to the Midlands and beyond.

A range of other work including drainage, earthworks, utilities, surfacing, and safety barrier works, will also be carried out.

(Picture: National Highways)