The Highways England scheme will see the road and footpaths being resurfaced along with improvements to the drainage system, reducing the likelihood of flooding or surface water.
The project will affect the section of the A595 between Calder Bridge and the junction with the B5345, just south of Thornhill, and includes resurfacing a one and a half mile stretch between Calder Bridge and Blackbeck roundabout. New signs and reflective road studs will also be installed and road markings will be replaced.
Temporary traffic lights will operate at off-peak times during the day, between 9.30am and 3.30pm for approximately 7 weeks, and also overnight, between 8pm and 6am, for approximately 12 weeks.
A temporary 40mph speed limit will also be in place while the work is carried out, and vehicles will be led through the roadworks in convoys on some occasions.
Peter Gee, Project Manager at Highways England, said:
The A595 is on a key route to Sellafield and is heavily used by local people and businesses.
The work we’re carrying out over the next few weeks will result in improvements for both drivers and pedestrians, as we’re resurfacing the road and footpaths as well as upgrading the drainage system.
We’re encouraging people to allow extra time for their journeys as there are likely to be some delays while we carry out this improvement work.
The project to upgrade the two-mile stretch of the A595 near Sellafield is due to be completed by the end of August.
Members of the public should contact the Highways England customer contact centre on 0300 123 5000.
Journalists should contact the Highways England press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.