The latest stage of improvement work along the A582 will go ahead at the Pope Lane roundabout.
The existing roundabout will be converted into a traffic signal-controlled 'crossroad' junction with additional lanes created on each of the four approaches.
This work will provide extra capacity to improve traffic flow at the junction and on the approaches. It will also create new safer crossings for cyclists and pedestrians.
Preparatory site clearance and utility work is currently scheduled to start on Monday 11 July, and will continue into August, with the main junction work following in September.
The project is expected to be completed by summer next year.
County Councillor John Fillis, Cabinet member for highways and transport, said: "This is the latest stage of our major plans to upgrade the whole length of the A582 to a dual carriageway.
"The A582 has suffered from significant congestion at peak times of the day, so the aim is to increase the road capacity and reduce congestion.
"This will improve the connection from Preston city centre, across South Ribble, connecting to the motorway network.
"We'll be working to minimize the disruption caused by this work, and people will need to allow extra travel time in this area while this work is carried out.
"Through City Deal we're improving the road to provide extra capacity and help people to get around the area. This will also help to unlock the economic potential of the area by creating new commercial opportunities, which will provide new jobs and growth."
Local residents and businesses have been informed about this work at Pope Lane.
Over the past two years, the county council has been making improvements to add capacity to the A582 and reduce delays on this key route in and out of Preston. We've already seen improvements along the A582 including the Broad Oak roundabout, close to Booths supermarket. A section from Broad Oak has already been upgraded and other roundabout have been widened.
The upgrading of the A582 is one of the four major road schemes included in the Preston, South Ribble and Lancashire City Deal.
To find out more visit www.lancashirelep.co.uk/city-deal
email citydeal@lancashire.gov.uk
or call 0300 123 6780.
Keep updated on highway improvement work taking place by following @LancsCityDeal on twitter.