Work is to get under way this month to improve surface water drainage at the bottom of Richmond Hill in Braddan.
It aims to deal with issues of water lying on the carriageway especially in winter months.
Preparative work began this week with exploratory trenches being dug and the site set up for the scheme.
Two-way temporary traffic lights will be in place for 24 hours a day until the end of the working day on Tuesday, May 11.
The main part of the scheme will get underway on Thursday, May 20, with an anticipated completion date of Saturday, July 24.
Richmond Hill will remain open to two-way traffic throughout, but with one lane at a time being closed, and traffic controlled by temporary two-way traffic lights.
The speed limit will be reduced to 30mph during the main period of the works.