The project on the A4 between the Twerton Fork and the Globe roundabout at Newton St Loe is part of a package of resurfacing schemes being carried out by Bath and North East Somerset Council.
The authority has largely completed the resurfacing of the A4 on the other side of Bath, at London Road, and has finished work at North Parade.
But it has yet to start on another potentially disruptive project - laying a new surface at Churchill Bridge.
The work to the west of Bath began on Monday and will go on for more than a month, although it will stop for the Easter Bank Holidays.
It will include the roundabout itself, the stretch to Twerton Fork, and Newbridge Road between that junction and the Newbridge Park and Ride site.
The council has warned there will be lane closures and a contraflow system, with one side of the dual carriageway being done at a time.
Some work at the roundabout and the junction itself will be done at night.
Other projects looming include the resurfacing of Pulteney Bridge and part of Argyle Street next week, with evening or night closure, and of part of Claverton Street, also next week.
The Churchill Bridge work will now not begin until after April.
For more information, email transportation@bathnes.gov.uk or call Council Connect on 01225 394041.
The council says the dates and times may change due to bad weather.