From the looks of it they are installing traffic lights.
There will be closures and diversions
Northbound – Thursday 20 September for 10 weeknights and Monday 29 October for 5 weeknights
Southbound – Monday 22 October for 5 weeknights:
Total Closure – Friday 9 November for 1 night:
Details of the closures can be found here
Details of the scheme can be found here