Highways England has stated it 'hopes' to complete the work at Stockbridge Roundabout, Chichester, 'within a month'.
The project, which started on January 8, was scheduled to last for 12 weeks so should have concluded last Friday.
However, a spokesman for Highways today said: “Due to unforeseen circumstances, including the recent severe weather, this work at Stockbridge has unfortunately been slightly delayed.”
They added Highways was 'unable to confirm a completion time at this point'.
Originally the work was set for last September but a change to designs saw it postponed.