The lights will be in place for at least the next fortnight while the remaining works are completed and are for the protection of both the workforce and road users.
The morning traffic control currently in place for Seaford College will cease after tomorrow morning (Friday).
The section of road, just south of the Seaford College entrance, has been closed for safety reasons following a slippage of earth over a culvert that spans beneath the carriageway.
Businesses in Duncton, Petworth and the surrounding areas have been able to open as usual throughout and will continue to do so.
More information is available at www.westsussex.gov.uk/duncton