The next phase of a development which is set to bring more than 3,000 jobs and an economic boost of nearly half a billion pounds begins this week.
Durham County Council is to start the next phase of work to expand Aycliffe Business Park.
The park, which is already the largest site of its kind in the region is to be added onto the 52 hectare Forrest Park site in Newton Aycliffe.
The site, for which the Local Enterprise Partnership has provided £13m funding, will be the subject of a £140m private sector development including a potential rail freight interchange.
It is estimated the site could see the creation of 3,200 jobs and deliver a Gross Value Added boost of £495 million over the next twenty years.
Preparation groundworks began last year.
The enabling works are now set to continue with the creation of a new traffic light controlled junction on the A167 - for better access to both the new site and the business park.
Work on the junction and resurfacing of an adjoining stretch of the A167 got underway on Thursday 24 August.
The southbound dual carriageway will be resurfaced between its junctions with the B6444 St Andrew’s Way and the A1(M) junction 59 interchange, with that section of road closed to allow the work to take place on Thursday 24 and Friday 25 August.
Diversions will be in place.
Leader of the council Cllr Simon Henig said:
The development of the Forrest Park site has the potential to bring thousands more jobs to County Durham and could be worth almost half a billion pounds for our economy.