National Highways is starting the installation of narrow lanes around Junction 9 of the M3 over the next few weeks, reducing speed limits to 50mph at the same time.
The work will be done in phases overnight, with closures in place to accommodate the work.
The first planned closure will be from April 22 to April 25, with the M3 Southbound carriageway closed between Junctions 8 and 10 from 9pm to 6am.
There will then be closures at the A272/Spitfire Link at Junction 9 from 7pm to 8am on April 26, and from 7pm to 6am on April 27.
The A34 Southbound at Three Maids Hill and A33 Southbound at the Cart and Horses Junction will be closed from 9pm to 6am on May 1 and May 2.
After that, the M3 Northbound carriageway will be closed between Junction 11 and Junction 8 from 9pm to 6am between May 6 and May 8.
Finally, from May 15 to May 16, the M3 Junction 9 northbound carriageway will be closed between its slip roads from 9pm and 6am.
As previously reported, it is hoped that the new design will also improve safety by extending the southbound slip road onto the M3 so traffic has more time to join the motorway.
More information about the works and diversion routes can be found by visiting nationalhighways.co.uk/our-roads/south-east/m3-junction-9-improvements/.
