Part of Ring Way in Preston city centre will be closed this weekend for investigations into a road collapse.
Lancashire County Council will be closing the northbound side of Ring Way heading away from the city centre from just north of Lawson Street to the junction with North Road from 6am on Saturday 30 May.
A lane closure was put in place on Thursday due to a depression emerging in the road surface, and work is now urgently needed to find the cause and make a repair.
Until investigations have taken place it is not known when Ring Way will fully reopen.
A diversion will be signed via Lawson Street, Walker Street, Lancaster Road, Melling Street and North Road. A temporary bus stop will be in place on Lawson Street for passengers who would like to get off before reaching the bus station.
Rob Wilson, area highways manager for Lancashire County Council, said: “We’re sorry for any disruption due to the need to close Ring Way this weekend, however it’s vital that we investigate the cause of the road collapse.
“Unfortunately we can’t say when we’ll be able to reopen the road until we’ve found the cause of the problem, however we’ll be working throughout the weekend as necessary to try to get it repaired as quickly as possible.”