Work to install a footbridge near the A27 at Chichester gets underway on Monday (January 8), meaning lane closures will be in place along stretches of the road, according to Highways England.
There will be lane closures in both directions between the Fishbourne roundabout and the Bognor Roundabout, starting on Monday, between 8pm and 6am.
The lane closures will be in place for five nights.
From Saturday, January 13, at 6am there will be a 24-hour speed restriction of 50 mph, as well as a dedicated slip road closure on the westbound carriageway at Stockbridge roundabout.
This will remain in place for the duration of the scheme.
Highways England said work is scheduled to be complete by mid March 2018.